Asking For Help - Brake Bleeding Issues

[Hacksaw84]

I have been working at this for a while and feel like I have tried everything and am a little stumped. Figured I would reach out to this wealth of knowledge to get some additional input.

Here is whats going on:
I basically have no pedal and very minimal clamping force all the way around. Both with the car off and running. No real difference.

Here is my brake setup:
Starting with a triple reservoir, two of the hoses (Front and Rear) go to the top of each port on the Hydroboost Master Cylinder. The side ports have -AN banjo fittings to hard line. Both hard lines go to a 2008 GT500 ABS module. From there its individual hard lines to each caliper (well SS flex line at the calipers). I have mustang 98 (ish) cobra brakes for the fronts and 2015 mustang calipers in the rear. All the calipers have been re-built. The calipers all have speed bleeders with sealant on them. I am using DOT3 brake fluid. My pedals are Wilwood and the Hydroboost is the one from Forte specifically modified to work with this setup.

Bleeding/Troubleshooting I have done:
1) I started by bleeding all 4 corners in the normal pattern. I have used the vac hand pump at each caliper, used the power bleeder from the reservoir down, and used the old fashion way of pumping the pedal. Did this till I got no more bubbles but still had no pedal. I continued to bleed this way for several quarts at each corner. Ditched the first cycle of fluid in case it got dirty and have been re-using the "clean" fluid.

2) I talked to Mike about the issue to check and see if he had some ideas since the Hydroboost came from him. I loosened the MC from the spacer on the HB to make sure I was getting enough throw on the rod. When I did that I got no fluid pump at the caliper. It seemed like that wasn't the issue so tightened it back up as it was.

3) I have heard that it's common for air to get trapped in the ABS module especially if it gets completely dry (which mine was) so I bought a higher end scanner tool to auto bleed the module. I did that a bunch and it did free up some air bubbles at first. I continued bleeding and by using a combination of power bleeding from the top down, actuating the ABS module with the scanner, and pumping the brakes via the pedal I was able to get lots of tiny bubbles out. I did this over and over for a while and to the point where I was getting good clamping force (best I could tell with my hands) on the front. Although the pedal still didn't feel that firm. I moved onto the rear to continue this procedure. Got more small bubbles out and the rear brakes only slightly improved. Then double checked the fronts at the end and they seemed to get worse. I never got to the point where there were no bubbles.

Lots of small bubbles makes me think that air is getting in. But under pressure when using the power bleeder I am not leaking anywhere and when the system is all sealed up and I pump the pedal I also have no leaks. I would assume that if air was getting IN that I would also be able to push fluid OUT. Since its both front and rear it makes me think its either a Master Cylinder or ABS module issue since they impact both.

Will the MC allow air to get pushed in when the pedal is pumped without allowing fluid to get out?
Can I have a leak at a fitting (well it would have to be multiple fittings, front and rear) that allows air to get in the system without leaking out?
Is there a chance that I just have a crap ton of air in the ABS module and just need to keep bleeding these little bubbles out? Triggering the module with the scanner does seem to increase the bubbles. I don't know what this means but I do get the most bubbles (by far) with both the left calipers. Front left and rear left both get the majority of the bubbles. I dunno is that's the shortest path in the ABS module or what.
Or is the ABS module letting air get in but not fluid out?
Is my bleeding procedure adding air somehow? I have the Motive power bleeder, bought an extra lid for my reservoir, tapped the lid and plumbed the motive line into that.
I don't think its an issue with the calipers since it happens at all four corners.

One thing I have not tried is running the car and using the scanner to perform the auto bleed on the module. Its always been with the car off.
Another note is that I am troubleshooting my no power steering issue. Although two different systems they both run through the hydroboost. However the MC is really its own thing and even if I don't have assisted brakes I should still have pretty good "manual" brakes. Just figured I would get all the info out there. That's all I can think of.

Thanks in advance for your feedback.

[65 Cobra Dude]

Wish I had an answer for you Michael but I will be watching because I am working on a car with hydro boost and have similar symptoms,

Henry

[Hacksaw84]

Wish I had an answer for you Michael but I will be watching because I am working on a car with hydro boost and have similar symptoms,

Henry

Thanks Henry. I hope for both our sake its something easy.

I assume your car does not have ABS?

[65 Cobra Dude]

You are correct Michael, no ABS. Let’s wait for an expert to chime in!

Thx,

Henry

[Rdone585]

I don't have that setup, and haven't worked with it before. But, It appeared in your description that you may have worked on the front brakes first then moved to the rear (see point 3 in your initial post). I've always bleed starting at the caliper farthest from the master cylinder - R rear->L rear->R front->L front. If not you can go round and round trying to get all the air out. Another thought... I've had no success with speed bleeders. You can flush a brake system with them but to get a good pedal I've always had to do the manual pump-loosen-tighten-repeat process. You have to make sure the person loosing-tightening communicates well with the person pressing the brake pedal. Also - never ever let the master cylinder go dry, or you'll have to start the process all over. I know these are basic points you probably followed but I thought it good to state them.
I'll be listening for more info in case something else comes to mind.
Robert

[Hacksaw84]

I don't have that setup, and haven't worked with it before. But, It appeared in your description that you may have worked on the front brakes first then moved to the rear (see point 3 in your initial post). I've always bleed starting at the caliper farthest from the master cylinder - R rear->L rear->R front->L front. If not you can go round and round trying to get all the air out. Another thought... I've had no success with speed bleeders. You can flush a brake system with them but to get a good pedal I've always had to do the manual pump-loosen-tighten-repeat process. You have to make sure the person loosing-tightening communicates well with the person pressing the brake pedal. Also - never ever let the master cylinder go dry, or you'll have to start the process all over. I know these are basic points you probably followed but I thought it good to state them.
I'll be listening for more info in case something else comes to mind.
Robert

Yeah always appreciate it. I did bleed several times following the order you described. That is what I meant by "the normal process" in #1. I even did it again last night after bleeding more air bubbles. In #3 I was just talking about the ABS bleeding portion. I had read online that air will come out from the closest caliper which is what I experienced. For both the front and rear, which I believe are essentially 2 different systems. Separate reservoirs, ports on the MC, lines, ports on the ABS, etc. Not that it matters too much.

I have used both the power bleeder and the manual pumping. Its so much easier to use the power bleeder for all these little bubbles because it comes with lots of flow. But then also just go back to manual pumping at the pedal. At the calipers I have the speed bleeder screws with the one way valve that don't let air back in. They do work as intended I have checked them.

Yeah I have been very careful not to let it go dry. Always topping off properly before air gets in.

Again appreciate the comments.

[Jacob McCrea]

Hopefully this is of some help, despite not being the same setup: I have manual brakes and the typical Wilwood 3-master pedal box. I struggled tremendously to get the rear brakes properly bled. Gravity bleeding, typical 2-person bleeding, a handful of different bleeding tools all failed to solve the problem. There were no visible leaks. I'm no pro mechanic, but far from a novice. Eventually I got a firm pedal after tearing the rear master cylinder apart, cleaning it thoroughly, and making sure the passage from the reservoir to the plunger area was completely unobstructed. As far as I could tell, some debris was preventing the plunger area from filling and refilling with brake fluid each time I pumped the brakes. Hope this helps.

[Hacksaw84]

Hopefully this is of some help, despite not being the same setup: I have manual brakes and the typical Wilwood 3-master pedal box. I struggled tremendously to get the rear brakes properly bled. Gravity bleeding, typical 2-person bleeding, a handful of different bleeding tools all failed to solve the problem. There were no visible leaks. I'm no pro mechanic, but far from a novice. Eventually I got a firm pedal after tearing the rear master cylinder apart, cleaning it thoroughly, and making sure the passage from the reservoir to the plunger area was completely unobstructed. As far as I could tell, some debris was preventing the plunger area from filling and refilling with brake fluid each time I pumped the brakes. Hope this helps.

Yeah I have thought it may be an issue with the master cylinder. I hadn't really considered debris but that could definitely be an issue.

[JimC]

i struggled with bleeding manual brakes with wilwood components as well as bleeding my hydraulic clutch. Tried multiple approaches that did not work(probably something i did wrong as i am a newbie) The last thing i tried which did work quickly was to elevate my brake fluid reservoirs as high above the master cylinders as i could then using a plastic tubing placed over the bleeders one at a time so that they were sealed and ran this tube into the appropriate reservoir so that when i pumped the pedal i just circulated the fluid around and around until bubbles were gone.

[Hacksaw84]

i struggled with bleeding manual brakes with wilwood components as well as bleeding my hydraulic clutch. Tried multiple approaches that did not work(probably something i did wrong as i am a newbie) The last thing i tried which did work quickly was to elevate my brake fluid reservoirs as high above the master cylinders as i could then using a plastic tubing placed over the bleeders one at a time so that they were sealed and ran this tube into the appropriate reservoir so that when i pumped the pedal i just circulated the fluid around and around until bubbles were gone.

So basically created a closed loop of brake fluid from the caliper bleeder to reservoir, then pumped the pedal cycling the fluid around?

[JimC]

Yes, I was able to sit in the car and watch the tube clear up while pumping the brake, I think elevating the reservoirs helped as well.

[Rdone585]

As Jacob pointed out, you might carefully look at the MC if your still not able to get a good pedal - especially if it's a new MC. When I first put mine in there was a blench bleed procedure I followed before it was every mounted in the car.

[Hacksaw84]

Yes, I was able to sit in the car and watch the tube clear up while pumping the brake, I think elevating the reservoirs helped as well.

OK I can do that. Thanks.

[Hacksaw84]

As Jacob pointed out, you might carefully look at the MC if your still not able to get a good pedal - especially if it's a new MC. When I first put mine in there was a blench bleed procedure I followed before it was every mounted in the car.

Yeah I looked at the bench bleeding procedures people do (after mine was installed) and from what I can tell the hydroboost MC doesn't require it like the manual MCs? They don't have the same one way internal valving. I could be wrong.

[edwardb]

Yeah I looked at the bench bleeding procedures people do (after mine was installed) and from what I can tell the hydroboost MC doesn't require it like the manual MCs? They don't have the same one way internal valving. I could be wrong.

You keep bringing up hydroboost. That has no bearing on your bleeding process. The two circuits are completely independent. The hydroboost adds a power assist. But doesn't change the mechanism of how the brakes work or bleed. "Bench bleeding" is usually done on the car too. Probably should have a different name. It's the process of getting air out of the MC's before bleeding through the brake lines to the four corners. I've had 100% success with pressure bleeding. Always go farthest -> closest. Right rear, left rear, right front, left front.

The wildcard here could be the ABS system. But I don't know since I've never messed with one. I don't know if the valve solenoids are open or closed and whether brake fluid flows through them freely.

[Mastertech5]

Did you just put the calipers on or are you just upgrading the booster? I was watching a brake upgrade on youtube by a seasoned shop owner who put the rear calipers on the wrong sides resulting in the bleeders being on the bottom.. Can't get the air out that way. Just a thought.

[dhuff]

i used a pressure bleeder and attached it at the calipers. https://www.summitracing.com/parts/PSL-2104-B


I've never been able to bleed brakes so easily before.

[Hacksaw84]

You keep bringing up hydroboost. That has no bearing on your bleeding process. The two circuits are completely independent. The hydroboost adds a power assist. But doesn't change the mechanism of how the brakes work or bleed. "Bench bleeding" is usually done on the car too. Probably should have a different name. It's the process of getting air out of the MC's before bleeding through the brake lines to the four corners. I've had 100% success with pressure bleeding. Always go farthest -> closest. Right rear, left rear, right front, left front.

The wildcard here could be the ABS system. But I don't know since I've never messed with one. I don't know if the valve solenoids are open or closed and whether brake fluid flows through them freely.

Yeah I understand how the hydroboost or power brakes in general work. I just mention it because it not just the common Wilwood setup many guys have of even a Master Cylinder on a manual system. Although functionally the same.

I have bled farthest to closest. Several times. I think it is the wildcard of the ABS module that is my issue. Or at least my biggest issue.

[Ducky2009]

Bleeding with ABS is pretty simple. Turn the ignition on and apply light pressure on the brake pedal. Open the bleeder screw and allow the fluid to flow until clear. If the ABS system is working properly, it will pump the fluid for you. No additional suction or pressure systems are needed.

NOTE: This will drain the master cylinder in "seconds" if you open the bleeder too far.

[Hacksaw84]

Did you just put the calipers on or are you just upgrading the booster? I was watching a brake upgrade on youtube by a seasoned shop owner who put the rear calipers on the wrong sides resulting in the bleeders being on the bottom.. Can't get the air out that way. Just a thought.

The whole system is new. As it its the first time I have had it all together. Not like I'm adding in or swapping out components, if that makes sense.
I am pretty confident that the calipers are all on the correct sides. The bleeders are the top most point of the caliper. Appreciate the help trying to solve it.

[Hacksaw84]

i used a pressure bleeder and attached it at the calipers. https://www.summitracing.com/parts/PSL-2104-B


I've never been able to bleed brakes so easily before.

I have one that attaches to the calipers. Not the same design as that one but similar idea, pulls a vacuum at the bleeder screw. It did "work" but was probably the least helpful with all the air seem to have.

[Hacksaw84]

Bleeding with ABS is pretty simple. Turn the ignition on and apply light pressure on the brake pedal. Open the bleeder screw and allow the fluid to flow until clear. If the ABS system is working properly, it will pump the fluid for you. No additional suction or pressure systems are needed.

NOTE: This will drain the master cylinder in "seconds" if you open the bleeder too far.

I assume you mean the bleeder screw on the caliper? I have heard of some ABS modules having one but the one I have does not.

I have had the key on with the bleeder open and the ABS does nothing. Also on regular cars I have had over the years I have never experienced this. I found several people on mustang forums stating that you for sure have to use a scanner tool to actuate the module. That has been my experience too.

[Hacksaw84]

Update:
So I worked on bleeding the system for a LONG time today. I took JimC's advice and created a loop system of brake fluid. I attached the gallon tank from the power bleeder to the cap of my reservoir and then elevated the tank above the top of the cap so it had the gravity advantage and kept from introducing air. Then I bought a lot of clear tubing and ran each caliper bleeder screw back to the tank. The tube is all hanging from sting to it goes way up then down to the tank. I then cracked each bleeder individually and pumped and pumped and pumped and yep pumped the pedal. So many small bubbles. I would also occasionally run the auto bleed function with the scanner. A few times when I had solid section of bubbles I would hook the power bleeder back up and pressurize the line so I could speed up the process of flowing the bubbles. I did this for over 6 hours. It would go from no bubbles and all solid fluid to a random medium bubble or two then sometimes a bunch of little bubbles.

I got to the point where I almost have no bubbles in the front. One every once in a hundred pumps. Then I removed the tank from the front reservoir and went full old fashion with the pumping the pedal and slowing topping off the fluid level. I got to the point that the left front caliper is holding the rotor enough that I cannot spin it at all with my hand. The right front is better but still can spin it if i really put some muscle into it. The rears are improved but still spin with some effort. I was still getting air out of the lines in the rear pretty regularly. Towards the end of today one of the times I used the auto bleed function I felt a difference in the pedal and got an influx of tiny bubbles in the rear. Like to the point that it looked aerated.

In general the pedal feels 30% better but not firm. It does feel as though you are pressing fluid and not just all the way to the floor. The calipers are going in the right direction of more clamping strength but not in a timely manner. At this point I am guessing that its just air trapped in the ABS valves and I need to keep at it. I still don't have any leaks and I don't loose fluid when the system is all sealed up (aka bleeders not open). I assume that if a part was introducing air to the system I would have other symptoms and not be improving? I didn't do a bench bleed on the MC because I didn't want to open up the lines and add in air but I guess its a possibility that I also have air in there and am slowly getting it out as well?

That is it for now.

[Andrew Davis]

Michael,
had similar symptoms with my manual system, (Wilwood). Had air leaks in brass line fittings, reservoir o ring and 3 of 4 calipers. Per forum input, used thread sealant on NPT joints at calipers and tightened compression joints at line fittings. No leaks but still dealing with FF5 res drips. Hope it helps AD

[Jeff Kleiner]

Michael,
This is a simple one and just a spitball but have you tried doing away with the speed bleeders? Years ago I was visiting a buddy in Florida who was having fits getting a good pedal on a Firebird restoration. As a last ditch "Hmmm, I wonder if...?" we took the speed bleeders off and put the regular ones back in and after one more round of old fashioned 2 man bleeding had a rock hard pedal. Obviously the check valve was not fully seating in at least one of them and allowing air to be drawn back in. So, hmmm, I wonder if...?

Good luck man,
Jeff

[rich grsc]

Take a picture of the back side of the front calipers. You could have them on the wrong side. I don't remember what years, but with some fronts, it was easy to get them switched and trap an air bubble. I tried speed bleeder one time, could never get them to stop letting air back into the calipers around the threads. They promptly went into the round file.

[Hacksaw84]

Michael,
had similar symptoms with my manual system, (Wilwood). Had air leaks in brass line fittings, reservoir o ring and 3 of 4 calipers. Per forum input, used thread sealant on NPT joints at calipers and tightened compression joints at line fittings. No leaks but still dealing with FF5 res drips. Hope it helps AD

Starting from top. At the reservoir the brass NPT fittings have tread sealant. Then the MC top has thread sealant on those brass NTP fittings. The Banjo fittings coming out of the side of the MC use aluminum crush washers to seal the banjo bolt. The bottom of that fitting is -4an and no sealant bc the -4AN flare makes the seal. The other end of the hard lines going into and out of the ABS module are a single bubble flare and also use the flare as a sealing surface. Then all the rest of the brake lines are a double flare, again without sealant. The Stainless flex lines are -3 AN on one end and then use copper crush washers on the caliper banjo end. Have been checking all the fittings over and over and all are dry no leaking or small drips.

[Hacksaw84]

Michael,
This is a simple one and just a spitball but have you tried doing away with the speed bleeders? Years ago I was visiting a buddy in Florida who was having fits getting a good pedal on a Firebird restoration. As a last ditch "Hmmm, I wonder if...?" we took the speed bleeders off and put the regular ones back in and after one more round of old fashioned 2 man bleeding had a rock hard pedal. Obviously the check valve was not fully seating in at least one of them and allowing air to be drawn back in. So, hmmm, I wonder if...?

Good luck man,
Jeff

I could try that. Watching them work I really don't think they are doing that. When I push the pedal in and stare at the bleeder I can see a bubble come out and stay right by the bleeder and not get sucked back in. I actually started with regular ones and switched to these so it was a little easier to do all this by myself.

Whats driving me nuts is that it is an insane amount of air bubbles. Literally thousands. And it appears to be getting better. I pretty much am not getting any more out of the fronts, just the rears now. =

[Hacksaw84]

Take a picture of the back side of the front calipers. You could have them on the wrong side. I don't remember what years, but with some fronts, it was easy to get them switched and trap an air bubble. I tried speed bleeder one time, could never get them to stop letting air back into the calipers around the threads. They promptly went into the round file.

I have checked this before but went out there and did it again just now. All the R's are on the passenger and all the L's are on the driver. Plus I am pretty sure if I had them swapped then the bleeder screws wouldn't be the highest point on the caliper for bleeding (which they are). Again I do think the speed bleeders are working properly. They do have thread sealant on them new. I actually added more to one because it seemed to have worn off from all the tightening and loosening. If the threads were not sealing properly when loosened wouldn't brake fluid lead out when the screw is loose for bleeding and I have the system providing positive pressure? Either by pumping or the pressure bleeder. I could understand air getting in if that was the case if I was pulling fluid under vacuum at the bleeder.

[Hacksaw84]

Update for today:
For anyone who cares... ;)
So I continued the cycle of bleeding where I essentially have a closed loop of brake fluid from the caliper back to the reservoir. The fronts seem to have no more air. I worked on the rears a lot more today and got a good amount of air out of the rears. Again when triggering the ABS module with the scanner. I eventually got to the point where I was not getting any more bubbles by the end of the day.

I also decided to mess with the throw of the pedal. I adjusted the nut and threading of the the rod coming out of the hydroboost going to the Wilwood pedal arm. I got it where I seem to get the most effective throw on the Master Cylinder. I am not really sure if its right though. If I watch the fluid level on the reservoir and the output of the bleeder the first 1/4 of the pedal does nothing. Then its about 3/4 of actually moving fluid. Maybe less. I again tried loosing the bolts on the MC where it attaches to the HB spacer. This didn't seem to help. I suppose I need to call Mike and talk through this with him to be sure. I am curious to know how much should push out on each pump to know that I am getting the right hydraulic force? I know that isn't really an easy thing to measure.

I ended with the most basic two person procedure of bleeding. As always starting furthest and going closest. Making sure the fluid level never gets too low. Ran about 20 pumps though each caliper. Then I checked all four corners. The front two are hard to spin by hand but if I really try I can make it happen. The right rear takes a little force and the left rear isn't too hard to spin. The pedal still isn't firm. I would say it might be a slight improvement from where I ended yesterday but not much.

I did re-think the bleeder screws as several have mentioned. I do think the rears are letting a little bit of air in through the threads, not b/c the internal valve is bad, just because the sealant is worn off from unscrewing them so many times. Especially the left rear. Looking at the fluid in the clear tube when pumping the brakes you get a little bit of vacuum on the back stroke of the pedal and I assume its pulling a little bit of air in. If I am pumping with just the pedal a small amount of bubbles get added in but if I use the pressure bleeder its just fluid. Now this is NOT all the bubbles I have gotten. Just some tiny ones recently. So I guess I should replace those just to be 100% but I am not convinced its the only problem. On my last bleeding I made sure we pumped and held the pedal and only slightly had the screws cracked which should seal it up. On the fronts this does not happen at all.

Here are my thoughts on what it still could be (or a combination of these):
1) I am not getting a full throw on the rod and not at 100% pressure in the lines. This would explain the lack of clamping but not the lack of firmness in the pedal.
2) I have air in the master cylinder and need to "bench" bleed it.
3) I still have more air trapped in the ABS module. This seemed to have been at least part of the problem so far.

I really don't like having to ask for help and prefer to just figure it out but this has been very frustrating. I appreciate all the comment trying to help me solve it. I'm still very interested in what you guys think and recommendations on how to proceed. Thanks, Michael.

[65 Cobra Dude]

Michael, can you try loosening the master cylinder to see if it gets pushed out by the push rod? This will tell you if the push rod is too long not letting it fully return.

Just a thought,

Henry

[Hacksaw84]

I was pretty sure the answer was yes but I went ahead and double checked. When I loosen the MC and push the pedal it does move out the MC. I am not sure its only from the rod. Wouldn't the resistance of the fluid be enough to push against the MC? Should I crack the bleeder screws and try again?

[65 Cobra Dude]

Michael,

Really just want to loosen the MC and see if the pushrod is pushing it out without touching the pedal. This will tell you if the pushrod is too long.

Thx,

Henry

[Jacob McCrea]

Michael,

As Henry says, you don't want the master cylinder to be preloaded.

With the amount of fluid you've pushed through the system, plus the ABS triggering, I would think you would have overcome the lack of bench bleeding and air bubbles in the ABS many times over. This makes me think you are sucking air into the system each time you release the pedal. If I had to wager 100 dollars, I'd say your master cylinder seal is bad. Perhaps each time you press the pedal it creates enough pressure to seal up (not difficult when the lines are full of air), so you never see a leak out the back of the master. When you release it, there's no pressure on the seal, and probably a vacuum, and at that point you suck in air. I suspect the obstructed passage I mentioned in my first post would case the same problem.

Maybe buy 2 sections of steel brake line, run them into the output ports on the master, make some way to bleed the other ends with fittings, and thus make a "dead end" line for front and back ports of the master. Gravity bleed these "test lines" and see if the master cylinder will actually make pressure. If so, move on to the output ports of the ABS unit.

[Hacksaw84]

Michael,

Really just want to loosen the MC and see if the pushrod is pushing it out without touching the pedal. This will tell you if the pushrod is too long.

Thx,

Henry

Oh ok. I think the answer there is no. 99% sure on that.

[Hacksaw84]

Michael,

As Henry says, you don't want the master cylinder to be preloaded.

With the amount of fluid you've pushed through the system, plus the ABS triggering, I would think you would have overcome the lack of bench bleeding and air bubbles in the ABS many times over. This makes me think you are sucking air into the system each time you release the pedal. If I had to wager 100 dollars, I'd say your master cylinder seal is bad. Perhaps each time you press the pedal it creates enough pressure to seal up (not difficult when the lines are full of air), so you never see a leak out the back of the master. When you release it, there's no pressure on the seal, and probably a vacuum, and at that point you suck in air. I suspect the obstructed passage I mentioned in my first post would case the same problem.

Maybe buy 2 sections of steel brake line, run them into the output ports on the master, make some way to bleed the other ends with fittings, and thus make a "dead end" line for front and back ports of the master. Gravity bleed these "test lines" and see if the master cylinder will actually make pressure. If so, move on to the output ports of the ABS unit.

Ok, I don't think I am preloaded.

By the end of yesterday I was not getting any more air bubbles. For sure none in the front and pretty sure none in the rear. But I was kinda over it by the end of the day.

I guess I am not following you here. What do you mean by "make some way to bleed the other ends with fittings"?

[Jeff Kleiner]

I guess I am not following you here. What do you mean by "make some way to bleed the other ends with fittings"?

I think what Jacob is suggesting is to make a miniature brake system using only hard line so that you can determine if the master cylinder is capable of making and holding pressure rather than allowing it to "push through". A couple feet of line with a cap on the end would do. As he said, gravity bleed and cap them then pressure bleed by applying pressure and opening the cap to allow any air to escape---same as a bleeder on the caliper. This test will take everything but the master cylinder out of the system.

Jeff

[Jacob McCrea]

Yes, that is exactly what I am saying.

[Hacksaw84]

I think what Jacob is suggesting is to make a miniature brake system using only hard line so that you can determine if the master cylinder is capable of making and holding pressure rather than allowing it to "push through". A couple feet of line with a cap on the end would do. As he said, gravity bleed and cap them then pressure bleed by applying pressure and opening the cap to allow any air to escape---same as a bleeder on the caliper. This test will take everything but the master cylinder out of the system.

Jeff

Ok I get it now. Should I try and measure that pressure? I mean the MC is clearly making some kind of pressure. So even if I make this how do I really know its enough pressure. Unless the test is to see if the MC is allowing air to enter.

The other idea I had was to remove the hard line from the MC that supplies the ABS module and make a line to run it directly to the left front caliper. Basically the same thing but a dedicated short line to just the one caliper and then see how much clamping force I get that way. I was just trying not to introduce air in the line but I suppose I am past that at this point.

[Jacob McCrea]

"Ok I get it now. Should I try and measure that pressure? I mean the MC is clearly making some kind of pressure. So even if I make this how do I really know its enough pressure. Unless the test is to see if the MC is allowing air to enter."

That's what the test is for - to see if that master cylinder will build pressure/bleed properly, and remain in that state regardless of how many times you press the pedal. One of two things will likely happen if you build this little test system I describe: 1) the pedal will get rock hard and stay that way, regardless of how many times you press on the pedal. That will tell you the master cylinder is good and is not sucking in air. 2) You will get a decently hard pedal initially, but the more you pump the brakes, the more air will get sucked in, and eventually you will be back to a soft pedal. That will tell you the master is bad.

EDIT: If you want to bypass the ABS unit and just run the line(s) coming out of the master (I assume there are 2 but I don't know) to the front brakes, that would pretty much do the same thing I am suggesting, albeit with a few more points for air to enter. Hence my suggestion to make a test system that eliminates all other points of leaks but the master.

[Hacksaw84]

"Ok I get it now. Should I try and measure that pressure? I mean the MC is clearly making some kind of pressure. So even if I make this how do I really know its enough pressure. Unless the test is to see if the MC is allowing air to enter."

That's what the test is for - to see if that master cylinder will build pressure/bleed properly, and remain in that state regardless of how many times you press the pedal. One of two things will likely happen if you build this little test system I describe: 1) the pedal will get rock hard and stay that way, regardless of how many times you press on the pedal. That will tell you the master cylinder is good and is not sucking in air. 2) You will get a decently hard pedal initially, but the more you pump the brakes, the more air will get sucked in, and eventually you will be back to a soft pedal. That will tell you the master is bad.

EDIT: If you want to bypass the ABS unit and just run the line(s) coming out of the master (I assume there are 2 but I don't know) to the front brakes, that would pretty much do the same thing I am suggesting, albeit with a few more points for air to enter. Hence my suggestion to make a test system that eliminates all other points of leaks but the master.

Yeah I am fully following now. I think I can figure out a way to do this pretty easily. This is a great troubleshooting suggestion. Appreciate it!

[nuhale]

Forgive me if there isn't relevance to the overall discussion as I'm just reading some of this now. The Forte MC/Hydro assist is a little challenging with the function. I have found that you need both circuits front/back bled for it to work correctly without hydro assist functioning (engine running with pump providing pressure). The push rod from the hydro assist does not have ample travel without hydro pressure from the engine. I ran into this a few months ago and spent way too much time on this. If you did a trial on the tandem MC with only fronts it doesn't surprise me that you didn't get brake caliper pressure. The mechanical rods in the MC don't contact because the hydro assist rod doesn't have the travel.

Also I tried just about everything to bleed the system. I found success by taking it apart, setting the rod to correct length (about .010-.015 gap to MC seat), bench bleeding the hell out of it to assure no air and finally using a hand made pressure bleeder I made with a garden sprayer.

Happy to help if I can with detail, just PM me.

[Hacksaw84]

Forgive me if there isn't relevance to the overall discussion as I'm just reading some of this now. The Forte MC/Hydro assist is a little challenging with the function. I have found that you need both circuits front/back bled for it to work correctly without hydro assist functioning (engine running with pump providing pressure). The push rod from the hydro assist does not have ample travel without hydro pressure from the engine. I ran into this a few months ago and spent way too much time on this. If you did a trial on the tandem MC with only fronts it doesn't surprise me that you didn't get brake caliper pressure. The mechanical rods in the MC don't contact because the hydro assist rod doesn't have the travel.

Also I tried just about everything to bleed the system. I found success by taking it apart, setting the rod to correct length (about .010-.015 gap to MC seat), bench bleeding the hell out of it to assure no air and finally using a hand made pressure bleeder I made with a garden sprayer.

Happy to help if I can with detail, just PM me.

Well its good (and I guess bad :p) to know someone has been in a similar situation. Very much appreciate the response.

Where exactly do you measure that rod length/MC gap? Also, what did you do for bench bleeding to make sure it was air free?

Thanks again, Michael

[nuhale]

I used a bleeder kit and kept pumping the tandem MC until I saw no air coming out of it.... Then I pumped it 20-30 times more! This was off the car on a bench.

If you unbolt the MC from the hydro assist there is an adjustable push rod. Using a set of calipers, some note paper and some old school math measure it all up to assembly. The rod should seat in the MC holster -.010-.015".

[Hacksaw84]

I used a bleeder kit and kept pumping the tandem MC until I saw no air coming out of it.... Then I pumped it 20-30 times more! This was off the car on a bench.

If you unbolt the MC from the hydro assist there is an adjustable push rod. Using a set of calipers, some note paper and some old school math measure it all up to assembly. The rod should seat in the MC holster -.010-.015".

Ok cool.

Did you use the syringe type bleeder? Then force fluid down through the top? I suppose I can rig something up for the output of the MC but most kits I have seen have NPT or 'non banjo' fittings for the output. Mine (and I assume your did to?) has a banjo out the side as the output.

[nuhale]

No, I made a pressure bleeder using my MacGyver skills and a late night trip to Menards. I'm using the Scotts Hotrods reservoir so not very big. Used a 1" stool foot as the adapter to the reservoir with a worm drive clamp. There are some available online for around $100. I'm sure they are great but think I spent around $25 and a little time building one. For me it was worth it. You fill the garden sprayer with fluid, pump around 10lbs of pressure (installed a cheap pressure gauge), clamp the trigger open and open the bleeder valve on the brake caliper. Pressure forces the fluid thru the system no muss no fuss and is a simple one person job. I had it drain into a glass jar so no mess. I posted this in my build thread. Feel free to PM me with any questons.

post #17
https://thefactoryfiveforum.com/showthread.php?34938-NUHale-s-MKIV-7275-Build-Thread&p=405124&viewfull=1#post405124

[Hacksaw84]

No, I made a pressure bleeder using my MacGyver skills and a late night trip to Menards. I'm using the Scotts Hotrods reservoir so not very big. Used a 1" stool foot as the adapter to the reservoir with a worm drive clamp. There are some available online for around $100. I'm sure they are great but think I spent around $25 and a little time building one. For me it was worth it. You fill the garden sprayer with fluid, pump around 10lbs of pressure (installed a cheap pressure gauge), clamp the trigger open and open the bleeder valve on the brake caliper. Pressure forces the fluid thru the system no muss no fuss and is a simple one person job. I had it drain into a glass jar so no mess. I posted this in my build thread. Feel free to PM me with any questons.

post #17
https://thefactoryfiveforum.com/showthread.php?34938-NUHale-s-MKIV-7275-Build-Thread&p=405124&viewfull=1#post405124

Ok sending you a PM.

[Duster]

I had non stop problems with the MCs being bled. Not like a "normal" car that you can do literally on the bench. What did it for me was to go back to square one at the fitting to the rear of the MC that runs out to the front and rear brake line plumbing. A friend applied a small but consistent pressure to the pedal while I broke the line loose from the MC. Did this about a dozen times with constant checking of the resorviors for fluid. Finally I was able to burp all the air out of each of the MCs in this fashion. It makes a heck of a mess with the fluid. Need lots of paper towels. Afterwords I gravity bled the system, one front and one back wheel at a time. I have never like gravity bleeding but followed someones lead on the forum and it worked perfectly. I stopped working on the car for a month because I could not get over the brakes issue. Very frustrating. Good luck.

[Hacksaw84]

I had non stop problems with the MCs being bled. Not like a "normal" car that you can do literally on the bench. What did it for me was to go back to square one at the fitting to the rear of the MC that runs out to the front and rear brake line plumbing. A friend applied a small but consistent pressure to the pedal while I broke the line loose from the MC. Did this about a dozen times with constant checking of the resorviors for fluid. Finally I was able to burp all the air out of each of the MCs in this fashion. It makes a heck of a mess with the fluid. Need lots of paper towels. Afterwords I gravity bled the system, one front and one back wheel at a time. I have never like gravity bleeding but followed someones lead on the forum and it worked perfectly. I stopped working on the car for a month because I could not get over the brakes issue. Very frustrating. Good luck.

Thanks man. Yeah I have decided to go back to the the MC and start over. I pulled it last night and will be bench bleeding it.

What was the process you followed for gravity bleeding?

[Duster]

About the same as pressure bleeding for set up. I have to MCs (front & rear) and two seperate fluid reservoirs and I am assuming you do too.
I got two 12 oz. plastic bottles and clear plastic hose to fit the bleeder valves to drain from the bleeders down to the bottles. I drilled two holes in the bottle lid, one as a vent and one to fit the plastic hose into. Add about 1 1/2" of clean brake fluid to the bottles and make sure the hose ends are down in the brake fluid at the bottom of the bottle. Attache the other end of the hose tightly to the bleeder valve. I did one front caliper and one rear at the same time, both furthest from the MC.

Next I unscrewed the fluid reservoirs lids and pulled them. Keep an eye on the fluid levels because if these go dry you will need to start all over from scratch. As soon as I opened the lids I could see movement in the tubes at the bleeders. It took about 15 minutes and the fronts had pushed out all the air. The fluid began to move a bit quicker at this point. Keep an eye on the reservoir! The rears took longer, about 45 minutes in my case, but cleared up pretty well.

After messing with it for about an hour total I locked down the passenger side and repated om the drivers side. Went much quicker. When that side was done locked everything down and I had a pretty solid brake pedal. Because of the way I am (and how easy it was) I repeated this process 3 times over the next week. I could let them bleed and work on something else and go back and forth etc. I did get a couple of bubbles out of each end the second time which made me feel good. Very solid pedal and easy to do by yourself.

One other thing with the Wilwood MC / pedal box. This has to do with traditional pressure bleeding. Because the pedal rod pushes on both MCs at the same time Wilwood wants you to bleed both MC at the same time. So three people - one for the pedal and 1 each at a front caliper and a rear caliper. I started this way when I began this whole process and could never achieve any pedal pressure due in part to not having the MC well bled.

Good luck Michael

[Hacksaw84]

About the same as pressure bleeding for set up. I have to MCs (front & rear) and two seperate fluid reservoirs and I am assuming you do too.
I got two 12 oz. plastic bottles and clear plastic hose to fit the bleeder valves to drain from the bleeders down to the bottles. I drilled two holes in the bottle lid, one as a vent and one to fit the plastic hose into. Add about 1 1/2" of clean brake fluid to the bottles and make sure the hose ends are down in the brake fluid at the bottom of the bottle. Attache the other end of the hose tightly to the bleeder valve. I did one front caliper and one rear at the same time, both furthest from the MC.

Next I unscrewed the fluid reservoirs lids and pulled them. Keep an eye on the fluid levels because if these go dry you will need to start all over from scratch. As soon as I opened the lids I could see movement in the tubes at the bleeders. It took about 15 minutes and the fronts had pushed out all the air. The fluid began to move a bit quicker at this point. Keep an eye on the reservoir! The rears took longer, about 45 minutes in my case, but cleared up pretty well.

After messing with it for about an hour total I locked down the passenger side and repated om the drivers side. Went much quicker. When that side was done locked everything down and I had a pretty solid brake pedal. Because of the way I am (and how easy it was) I repeated this process 3 times over the next week. I could let them bleed and work on something else and go back and forth etc. I did get a couple of bubbles out of each end the second time which made me feel good. Very solid pedal and easy to do by yourself.

One other thing with the Wilwood MC / pedal box. This has to do with traditional pressure bleeding. Because the pedal rod pushes on both MCs at the same time Wilwood wants you to bleed both MC at the same time. So three people - one for the pedal and 1 each at a front caliper and a rear caliper. I started this way when I began this whole process and could never achieve any pedal pressure due in part to not having the MC well bled.

Good luck Michael

Ok thanks for the details. I might have to give that a try.

I don't have the Wilwood MC/Pedal box setup but I do think my master cylinder was part or much of the recent problem. Working on getting that squared away.

[Hacksaw84]

Ok so I think I solved my issue(s) or at least made it a LOT better ;). I appreciate all the comments, especially from nuhale.

I put everything back together and went on a test drive this weekend. It seemed like everything worked well. I only took the car around the neighborhood a few times and no hard braking was done but it did feel good just regular driving. Here is the list of things that got me there:

1) I had air in the ABS module. This was a pain to get out and I don't see how you could do it without a scan tool that triggers the module. I bought the Autel MaxiCheck Pro off amazon. It worked for the GT500 module I have. I ordered another one first that didn't work and I had to return it.
2) The rod between the Hydroboost and master cylinder needed adjustment (made longer). I have the Forte setup and there is a spacer between the HB and MC, in there is an adjustable rod. It needed lengthened to take up ALL the slack from pedal press to master cylinder engagement. Again thanks, nuhale.
3) The Master Cylinder needed to be bled individually. "Bench bled" per say but I did it with the reservoirs on the car attached, so not on the bench. One thing nuhale mentioned was that the throw from the pedal is significantly less than the MC itself when no boost is applied. I did confirm this between the MC and pedal but not with the car running and pressure applied. If you push the master cylinder in by hand you get a certain amount of throw/fluid movement. When it all bolted up and you use the pedal its at least half if not less than you see "bench bleeding". I think the only was to fully bleed it would be to do the MC off the HB. Or maybe with the car running, but I didn't test the fluid movement in that scenario.
4) I did wear out the thread sealant on the rear bleeders so I was getting a tiny amount of bubbles when if I loosened them enough. It wasn't making it worse just showing up in the line when bleeding. This was towards the end and I made sure I bled them properly and no air got back in.

Just sitting in the car without it running the pedal went from nothing (before) to what I would say is firm (after). Not "hard". I have not re-tested after driving around but the brakes all by them self (aka manual) without the HB are not equivalent to a straight up manual brake setup. I am going to test them driving and shutting the car off to see how they feel. I am not 100% sure everything is resolved but they felt good driving around the hood, I will continue to monitor them. Thanks again for the help.

[Mastertech5]

Round file those fast bleeders and buy some new regular ones specific for your calipers. The threads do not have to be sealed as the end is a taper and seals at the angle on the tip. if those bleeders aren't the right ones they won't seal properly. Hydroboost systems usually have a soft pedal when the engine is not running so you can't assume you have air by pedal feel. I had many a customer saying their brake pedal was soft and it ended up being normal because of the hydroboost.

[Mastertech5]

Round file those fast bleeders and buy some new regular ones specific for your calipers. The threads do not have to be sealed as the end is a taper and seals at the angle on the tip. if those bleeders aren't the right ones they won't seal properly. Hydroboost systems usually have a soft pedal when the engine is not running so you can't assume you have air by pedal feel. I had many a customer saying their brake pedal was soft and it ended up being normal because of the hydroboost.

[Hacksaw84]

Round file those fast bleeders and buy some new regular ones specific for your calipers. The threads do not have to be sealed as the end is a taper and seals at the angle on the tip. if those bleeders aren't the right ones they won't seal properly. Hydroboost systems usually have a soft pedal when the engine is not running so you can't assume you have air by pedal feel. I had many a customer saying their brake pedal was soft and it ended up being normal because of the hydroboost.

The bleeders seal fine when tightened up. I am not assuming there was air in there, I was getting it out of the system.

The system seems to be working OK now, but again have not had any serious braking to do.

[Mastertech5]

Good luck. Test them before you have to make a panic stop.

[Hacksaw84]

Good luck. Test them before you have to make a panic stop.

Thanks man. Yeah I have been testing them. A few drives around the hood and they seem good.

Will eventually do a few levels of panic stopping.