Need guidance Bleeding Brakes

[NA5KAR]

Hi Guys. Thanks in advance. Mk4 with standard FFR brakes. I have the brakes installed and the hard lines run. I am using the single fluid reservoir and the .75 front and .625 rear Wilwood master cylinders. The reservoir is the newer one. Not the one in the manual and Dan's build videos. When I first tried to bleed the brakes, there was a big fluid puddle under the drivers rear caliper. Removed it and saw that the dust boot was not seated properly in the caliper. Further inspection revealed a tear. Dave at FFR replaced the caliper for me. With the replacement caliper on, I'm trying to bleed the brakes. Starting at passenger rear. My son is pressing the pedal while I open the valve. There is good fluid flow but lots of bubbles in each pass. I've gone through almost a whole bottle of fluid and the bubbles keep coming. I tried bleeding the drivers rear and the same effect. I checked all line / fitting connections, under each caliper, under the reservoir, and under the master cylinders. No leaks. The pedal is not stiff. I've bled brakes successfully before. Getting frustrated. Would appreciate any suggestions.

[GoDadGo]

The balance bar dual MC set up can be a pain in the neck until you get accustom to it.

What worked for me was to Gravity Bleed the front first, staring with the longest line 1st, then gravity bleed the shorter run.
Repeat the process with the rear, starting with the longest run 1st, then the shorter run.
Once you've completed this task, then try depressing the brake with all the bleeds shut.
You will likely find that you've got a stiffer pedal, then repeat the process before playing the pump it, pump it, pump it bleeding the brakes game.

Remember to always start with the longest line 1st and always make sure you have adequate fluid in your reservoir or you'll be starting the brake bleed game all over.

Hope This Help & Good Luck!

[NA5KAR]

The balance bar dual MC set up can be a pain in the neck until you get accustom to it.

What worked for me was to Gravity Bleed the front first, staring with the longest line 1st, then gravity bleed the shorter run.
Repeat the process with the rear, starting with the longest run 1st, then the shorter run.
Once you've completed this task, then try depressing the brake with all the bleeds shut.
You will likely find that you've got a stiffer pedal, then repeat the process before playing the pump it, pump it, pump it bleeding the brakes game.

Remember to always start with the longest line 1st and always make sure you have adequate fluid in your reservoir or you'll be starting the brake bleed game all over.

Hope This Help & Good Luck!

I will do this first thing in the morning. Thanks a million.

[BEAR-AvHistory]

You can save a lot of frustration & fluid by power bleeding. Most auto supply mail order operations sell them. They have hand pumps so you don't need air if you don't have a compressor.

[Ducky2009]

Vacuum bleeders work great. Keep an eye on your fluid level... don't let it go dry or you'll be starting over.

[NA5KAR]

I tried vacuum bleeding with my Harbor Freight bleeder. Lots of bubbles. I appreciate the suggestion. I'll look into the power bleeder tonight. I'll do the gravity method in the morning and go from there. I didnt bench bleed the master cylinders. Forgot to mention that. Could this be the source of my issue?

[Papa]

Have you bled the mater cylinders? They should be bled before moving on to the calipers.

[NA5KAR]

Have you bled the mater cylinders? They should be bled before moving the calipers.

Hi Dave, I didn't bleed the master cylinders first. They are in place now. Can / should I still do that? If so, is there a procedure with them bolted in place?

[Papa]

Hi Dave, I didn't bleed the master cylinders first. They are in place now. Can / should I still do that? If so, is there a procedure with them bolted in place?

You should bleed them and it's easy to do with them in the car.

You just need to run a piece of tubing from each mater back into the reservoir. I made mine from left over 3/16 line I had an a couple of fittings. Disconnect the hard line fittings that go to your front and rear hard lines at the masters and connect the temporary lines in their place ensuring that they dump into the top of the reservoir. Be sure the reservoir is full and slowly pump the pedal until there are no bubbles coming out of the temporary lines. Once you have fluid only flowing, reconnect your hard lines to the cylinders and start your caliper bleeding. I prefer pressure bleeding, but you can try whatever method you wish. Be sure the reservoir never runs dry or you will get to start all over from the beginning.

[NA5KAR]

You should bleed them and it's easy to do with them in the car.

You just need to run a piece of tubing from each mater back into the reservoir. I made mine from left over 3/16 line I had an a couple of fittings. Disconnect the hard line fittings that go to your front and rear hard lines at the meters and connect the temporary lines in their place ensuring that they dump into the top of the reservoir. Be sure the reservoir is full and slowly pump the pedal until there are no bubbles coming out of the temporary lines. Once you have fluid only flowing, reconnect your hard lines to the cylinders and start your caliper bleeding. I prefer pressure bleeding, but you can try whatever method you wish. Be sure the reservoir never runs dry or you will get to start all over from the beginning.

Sound easy enough. That's what I'll do first then. I read in your build thread that you bench bled the masters and I had it in the back of my mind that I missed that step. Kinda hard to know what to do first when reading the manual, watching videos and reading the build threads. Thanks for your help.

[GoDadGo]

I didn't bleed my MC's and found that Gravity Bleeding the system a couple of times was quite effective.
Maybe I'm just luckier than most because I only had to play the pump it game once, maybe twice.
Good Luck & Happy Brake Bleeding!

[NA5KAR]

I didn't bleed my MC's and found that Gravity Bleeding the system a couple of times was quite effective.
Maybe I'm just luckier than most because I only had to play the pump it game once, maybe twice.
Good Luck & Happy Brake Bleeding!

That's a great point. It's a lot easier than cracking open the hard lines at the MC's. I'll give that a go first. I'll report my results. Thanks a million.

[GoDadGo]

That's a great point. It's a lot easier than cracking open the hard lines at the MC's. I'll give that a go first. I'll report my results. Thanks a million.

I did it at the wheels bleeds and it worked fine, but I guess you can loosen them at the MC, but it could get messy.
Please know that I just did them one at a time so that I could easily keep the reservoirs filled.
Starting the longest run first seemed to work well in my case.

[BB767]

Pressure bleeding (not vacuum). That is the only way mine would stop drawing in air. I struggled for days until I figured this out. Read some of the posts how to do it and DO NOT over pressurize it!

My theory is, the master cylinder rubber plunger seals are so soft and flexible when new that they easily allow air to be pulled by them when ANY small amount of suction is applied. Even the very slight amount you would get when drawing fluid into the master cylinder from the reservoir after bleeding a line. Perhaps if the reservoir was raised higher above the master (thus more gravity pressure) this would not happen, but in these cars that is obviously not an option.

P.S. I had not heard about bench bleeding and had not done it. Pressure bleeding should help with that as well.

[BEAR-AvHistory]

Added two more catch jars so I could do all 4 at the same time without needing a helper.

https://thefactoryfiveforum.com/attachment.php?attachmentid=128452&d=1589646234

[zilverx]

I bench bled the M/Cs, then used gravity bleed on the calipers. Watch how far you open the bleed valves - air can actually be drawn through the threads making you think there is still air in the system,- I would watch fluid flow, bubble free, to the catch bottle, things looked great, and then a series of fine bubbles would appear, especially if I played with the bleed fitting. Also, make sure there is fliud in the catch bottle and the tube is submerged to eliminate the possibility of air being drawn back into the system before the bleeder can be closed

[NA5KAR]

Thanks for all the helpful advice. I did a Master Cylinder bleed on the car. I bought the Dorman kit at Pep Boys and discovered that it sucks. I used it the best I could though. Got the air bubble out by feeding the hoses from the MC exits to the reservoir. After I cleaned up the area, I tried to bleed the passenger rear. Lots of bubbles and a small leak. I think it was coming from the piston dust boot. I took the caliper off and took it apart. I replaced the piston seal and the dust boot with a new set that I had. Put it back together and installed it. No more leak. I was able to bleed it with my wife's help pressing the pedal. The two rear calipers are now free of bubbles. The fronts were fine. So here is a new question. When holding down the pedal, the front rotors cannot spin. Locked tight as they are supposed to be. The rear rotors can spin. A little resistance, but I can spin them by hand. If my wife pumps the brakes, after the second press, the rear pads grab with each press. Still wont lock up when holding the pedal down. Is this normal or maybe a balance bar issue? FYI, at full pedal press, the balance bar has the rear MC plunger fully into the MC and the front MC has the plunger only halfway in.

[nuhale]

Pressure (power) bleeding was a game changer IMO. I have FORTE hydroboost with the mustang brakes and quickly realized I was getting nowhere with traditional foot pedal or vacuum processes. My Harbor Freight vacuum bleeder found the trash in less than an hour.

Bench bleeding is key as well. Need to remove any air from master before bleeding. Other poster talked about a pretty cheap bleeder kit that just pumps back into reservoir. Very quick but a pain if your going backwards. Lessons learned. Lots of google videos out there on this process.

I did a little digging and found a couple options to buy one of these systems but all were pretty pricey. Recall the lowest option around $100. If you study what these are they are basically a garden sprayer with some hardware. A late night trip to Menards and a little bit of assembly I had one for about $20. Pick up a garden sprayer ($9), a pressure gauge ($3) and some random connection hardware. I'm using a Scottshotrods reservior so I used a 1" rubber stool foot as the adapter. Pops right over and clamp down with a worm drive clamp. 10lbs of pressure and PERFECTO! Cleaned out a pickle jar and added some clear hose as a run off for a no muss no fuss experience. Only trouble was the pressure gauge mount but just caulked the hell out of it and no problemo.

Used it for brakes and clutch. Worked like a charm.

https://thefactoryfiveforum.com/attachment.php?attachmentid=125388&d=1585702303

[CraigS]

A couple of thoughts.1- As zilverx says, the bleeder threads can leak which is why I don't like vacuum bleeding. It can bleed the system but you don't realize it because there continue to be bubbles in the hose coming from air leaking around the threads. So I much prefer pressure bleeding. Another source of pressure is a $10 fish tank air pump. Use any combination of fittings you can find to go from hose to reservoir. This is mine.
https://live.staticflickr.com/4588/39320475642_8b0a91d4fd_z.jpg (https://flic.kr/p/22UBHvd)Pressure Bleeder (https://flic.kr/p/22UBHvd) by craig stuard (https://www.flickr.com/photos/152454123@N04/), on Flickr
First I found a piece of radiator hose that fit the top of the reservoir and took it to the hardware store to cobble together stuff to reduce to the hose size coming off my pressure regulator. 2- W/ the dual MCs of the wildwood setup it's best, if using a pump the pedal technique, to do both right sides at the same time and then both lefts at the same time. The reason for this is this. Say you bleed the fronts and get them pretty good. Now, since the front has no remaining air in it, the front MC will not travel fully when you try to do a rear. It will only travel maybe 1/4 of it's full stroke. Because the balance bar will not allow enough angle, the rear MC never gets the piston pushed all the way to the bottom so some air can stay trapped. This is another great reason to go to pressure bleeding. 3- If you have to do a pedal technique, I have had some success w/ a hose on the bleeder going into the top of a jar w/ some brake fluid in it. But there can still be the problem of air leaking around the bleeder threads. So I really like to have a helper at the pedal. My technique.
a- person at bleeder (me) w/ bleeder closed says 'pump it up'.
b. pedal pusher puts 5-6 pumps and holds pressure on the pedal and says 'holding'. Does not come off the pedal until told to do so.
c. bleeder opens the bleeder and lets fluid run but not til it completely stops. Close the bleeder as soon as the flow slows some.
d. once bleeder is closed bleeder says 'pump it up'. Keep repeating and watching fluid level.
The overall idea is that the brake line is always under slight pressure when the bleeder is open so there is no chance of air getting into the line.

[House Money]

I too was having problems bleeding the brakes on my truck, I had bled the masters, gravity bled all 4 corners and tried vacuum bleeding with my very old Mityvac, nothing worked and I had a very soft pedal. I bought a Motive pressure bleeder, their model #250 as it came with multiple adapters, one of those fit my brake reservoirs perfectly.

One thing I did though was to use it dry - it is supposed to be filled partially with brake fluid and that gets pushed through the brake lines. I picked up a couple of quick disconnect fittings and just pump it up to 15 PSI, connect it to the reservoir and leave it like that for 10 to 15 minutes to be completely sure there are no leaks, and then start cracking bleeders and watch all the air bubbles come out!!

With this method you do need to make sure your reservoir(s) do not run dry, that is easy to do with the quick disconnect fittings, and no brake fluid mess. See attached picture.

128541

[Murd]

Thanks for all the helpful advice. I did a Master Cylinder bleed on the car. I bought the Dorman kit at Pep Boys and discovered that it sucks. I used it the best I could though. Got the air bubble out by feeding the hoses from the MC exits to the reservoir. After I cleaned up the area, I tried to bleed the passenger rear. Lots of bubbles and a small leak. I think it was coming from the piston dust boot. I took the caliper off and took it apart. I replaced the piston seal and the dust boot with a new set that I had. Put it back together and installed it. No more leak. I was able to bleed it with my wife's help pressing the pedal. The two rear calipers are now free of bubbles. The fronts were fine. So here is a new question. When holding down the pedal, the front rotors cannot spin. Locked tight as they are supposed to be. The rear rotors can spin. A little resistance, but I can spin them by hand. If my wife pumps the brakes, after the second press, the rear pads grab with each press. Still wont lock up when holding the pedal down. Is this normal or maybe a balance bar issue? FYI, at full pedal press, the balance bar has the rear MC plunger fully into the MC and the front MC has the plunger only halfway in.

Did you adjust the balance bar on an angle as per the wilwood instructions? Regardless I think if the rear Mc is going through it’s full travel you still have air. The rear should travel less than the front.
Possible the rear pistons are retracted too far? I can’t remember but you might have to put the parking brake on and off a few times to adjust them.
Good luck.

[NA5KAR]

Did you adjust the balance bar on an angle as per the wilwood instructions? Regardless I think if the rear Mc is going through it’s full travel you still have air. The rear should travel less than the front.
Possible the rear pistons are retracted too far? I can’t remember but you might have to put the parking brake on and off a few times to adjust them.
Good luck.

Thanks Murd. Your suggestion about the parking brake is interesting. The rear calipers have a 'screw in' type of piston. I don't understand how it is supposed to work, but I imagine that applying the parking brake will have an effect on the pressure of the pads. I'll definitely try that.

[NA5KAR]

Pressure (power) bleeding was a game changer IMO. I have FORTE hydroboost with the mustang brakes and quickly realized I was getting nowhere with traditional foot pedal or vacuum processes. My Harbor Freight vacuum bleeder found the trash in less than an hour.

Bench bleeding is key as well. Need to remove any air from master before bleeding. Other poster talked about a pretty cheap bleeder kit that just pumps back into reservoir. Very quick but a pain if your going backwards. Lessons learned. Lots of google videos out there on this process.

I did a little digging and found a couple options to buy one of these systems but all were pretty pricey. Recall the lowest option around $100. If you study what these are they are basically a garden sprayer with some hardware. A late night trip to Menards and a little bit of assembly I had one for about $20. Pick up a garden sprayer ($9), a pressure gauge ($3) and some random connection hardware. I'm using a Scottshotrods reservior so I used a 1" rubber stool foot as the adapter. Pops right over and clamp down with a worm drive clamp. 10lbs of pressure and PERFECTO! Cleaned out a pickle jar and added some clear hose as a run off for a no muss no fuss experience. Only trouble was the pressure gauge mount but just caulked the hell out of it and no problemo.

Used it for brakes and clutch. Worked like a charm.

https://thefactoryfiveforum.com/attachment.php?attachmentid=125388&d=1585702303

I'm gonna make this tomorrow and give it another try. Great idea. Thanks!

[phileas_fogg]

I seem to recall reading that the pressure should be kept really low - like 3 to 5 psi. There's a danger to ruining a seal in your master cylinder. The lower value will do the job I think, though it may take longer. If it were my car, I'd start low & adjust according to the results.


John

[NA5KAR]

I seem to recall reading that the pressure should be kept really low - like 3 to 5 psi. There's a danger to ruining a seal in your master cylinder. The lower value will do the job I think, though it may take longer. If it were my car, I'd start low & adjust according to the results.


John

Thanks John. I appreciate the heads up. I'll keep that in mind for sure.

[Murd]

Another common issue I haven’t seen mentioned: is the brake pedal arm hitting the crossbar of the frame when it is released? If so the MCs won’t retract all the way and allow fluid into the system from the reservoir. I had to cut the pushrods of my MCs shorter to get this setup properly, I think it’s fairly common?
Needs to be setup so the pedal arm has some free play before the frame, otherwise the MCs won’t fully release.

[DavidW]

The Motive Power bleeder works okay....maybe it will ruin the seals in your brake master cylinders causing you to chase what everyone calls air in the lines to end up replacing the master cylinders. Or you can use the Mityvac Vacuum Brake Bleeder and be done.
128580

[CraigS]

I agree w/ phileas. When I was discussing this w/ the folks at CNC they said use a max of 5#. That can make it a pretty slow process so I usually go to 10# but not over. I like House's idea of using that bleeder dry. You have an easily regulated pressure and a bunch of adapters so it can fit dang near every car. A couple of guys where I used to work had them and used them wet. Ever see what happens when using it wet and the adapter is accidently knocked of the reservoir? BTW one other tip from CNC was when, you have pressure hooked to the MC, never, never, ever touch the brake pedal.

[ptstew]

When using a pressure bleeder wet, as per usual directions, be absolutely sure that the hose connections are secure and that the hose itself is not deteriorated. When recently using my several year old Motiv unit the hose failed at the connection to the Motiv tank and sprayed brake fluid everywhere. What a job being sure I got that cleaned up. Good reason to use it dry.

[32J]

I'm trying to bench bleed my 2 3/4" master cylinders, currently mounted to the pedal box. Even when I don't see any air bubbles in the clear tubes back to the reservoir, the pedal still goes all the way to full travel. It never gets stiff, so to speak. Is this normal? Or, would expect the pedal to stiffen up quite a bit once all air has been removed from the MCs? I've also tried jacking up the front of the car to make the cylinders level, because normally they angle up towards the discharge end that goes to the brake lines.

(Okay, I think I got it. Waited a few minutes and gently tapped the lines to move the air bubbles to the top of the clear tubes. Then, I slowly released the brake pedal a bit at a time, allowing the bubbles to reposition at the top of the clear line. Repeat until pedal all the way back to start position, then I was able to push the bubbles all the way into the reservoir.)

[NAZ]

I'm usually bleeding brakes solo so I normally use a vacuum bleeder. But regardless of the different methods I use, I've never had trouble bleeding brakes -- any brakes. Can't even remember the last time I bench bled a master cylinder, probably been decades.

I suspect some have issues bleeding the brakes on these cars due to installation and set-up errors. Ensure the bottom of the reservoir(s) are above the M/C, that the M/C has full stroke without the pedal contacting anything, that the piston returns fully when the pedal is released, and if using a balance bar system, ensure the side gap clearance is set according to the manufacturer's specs. I've seen some systems installed with air traps that made bleeding impossible. For instance, adding a tee in the line to install a brake light pressure switch and orienting the tee so that air gets trapped. You'll never get a firm pedal. The way you run your lines can make a difference in how easy your system is to bleed. Trap a few micro bubbles here and a few more over there and before you know it, you can't get a firm pedal to save your life.

The procedure can be as simple as: Pump, pump, hold. Open bleeder and look for air bubbles. Close bleeder and release pedal. Repeat as necessary. And if I have a helper, that's usually how I do it. But I will attach a clear hose to the bleeder valve and dump the waste in a jar. If I have trouble, I troubleshoot the issue and correct whatever is causing the difficulty.

[J R Jones]

NAZ's advice is spot-on.
Your initial post is a bit confusing, were you bench bleeding on a bench and moved-on to the pedal box, or bench bleeding on the car?
Either way, you do not get a firm pedal until the air is out and the plumbing and bleeders are closed. The system should be hydraulically locked without an air cushion.
Your master cylinders(s) should be mounted with the discharge end high to allow you to bleed the bubbles out.
Sometimes the master cylinder does not give-up small bubbles easily. If you do have trouble, give the brake pedal a small push and watch the fluid passages on the bottom of the master cylinder, you might see micro bubbles vent and rise to the top. (not possible with remote reservoirs)
I too like vacuum bleeding solo, and pedal bleeding with an assistant. Be sure that the pedal operator does not lift until the bleeder is closed.
jim

[Railroad]

I have all Wilwood brakes and used the gravity bleed. Opening the caliper bleeders and waiting on a drip. I pump bleed all the calipers afterward and got a small amount of air on a couple. My point is, I have seen posted pics of hard tube plumbing from the master cylinders going up several inches above the master cylinders.
If you have plumbed your tubing having high points above the master cylinder, or the reservoir fluid level below the master cylinders, gravity bleeding is not likely to happen.
Pressure or vacuum bleeding might circumvent these conditions, but best to avoid them, IMO.

[32J]

Thanks everyone. Eventually got all the air out of the cylinders and then the lines. Took a while without a vacuum system, but got a firm pedal in the end.

[CraigS]

...
Be sure that the pedal operator does not lift until the bleeder is closed.
jim
This can not be emphasized enough. The person running the bleed screw is the boss and should explain to the person on the pedal; do exactly what I tell you nothing else. Almost every bleed screw I have touched will leak around the threads when it is not tightly closed. So, if the person lifts the pedal when it is still open, even w/ a hose going into a bottle of fluid, air will be sucked into the line through the leaky threads. This is also why I don't like vacuum bleeding. The system could be perfectly bled but vacuum on the bleeder will suck air around the threads and the bubbles will never stop.
Boss- 'pump it up'
Pedal Person- pump the brake pedal at a reasonable speed. 2-3 seconds per pump. At the start there may not be much of a buildup in firmness because there is a lot of air. So I recommend 10 pumps. Stop pumping and hold the pedal down and say 'holding'.
Boss- open the bleeder to let fluid out. Do NOT hold it forever. Hold just until the fluid/air flow slows, and close it. You want fluid still at a slight flow so there is always a tiny bit of pressure in the line. Close the bleeder and say 'pump it up'.
As you keep going, you should get building firmness in the brake pedal but it is not going to get to full hard until the last caliper is bled. A note on the Wilwood dual MC system. The balance bar can only change it's angle by so much. And that 'so much' is not enough to have one of the MCs fully bled (so it only moves a little) and allow the other MC to move fully until the piston bottoms out in the MC. This is why it is often recommended to bleed both one front and one rear at the same time. And that requires 3 people. And that is why I much prefer pressure bleeding. I can do it all myself. BTW you only need 5# w/ a max of 10# of pressure. Other than a Motive (or similar) bleed system, my favorite was one a friend developed- the cheapest fish tank air pump you can find.

[NAZ]

Craig, I suspect that many dislike the vacuum method because of the propensity to draw air past the threads of the bleeder. It makes it seem like a never ending stream of air in the system. It does take a bit of getting used to before you know when to stop bleeding.

For those new at this, pulling air around the threads of the bleeder during vacuum bleeding doesn't add air to the system as long as you close the bleeder with vacuum on the system. The air being drawn past the bleeder threads is on the atmosphere side of the valve. Closing the bleeder valve will not trap this air. But how do you know when all the air is out of the system? Close the bleeder valve and go push on the pedal, if it's firm you're done bleeding. That's the only way you know for sure regardless of the bleeding method.

On a system that has trapped air that won't bleed, your fluid discharged past every bleeder may have no bubbles for several strokes and you're absolutely sure that there is no air in the system. But you still get a spongy pedal. So you can't always rely on the absence of air bubbles past the bleeder valve as a measure of goodness. But the pedal test will indicate if there is a problem.

[J R Jones]

CraigS, NAZ, Fortunately bleeding is routine, but exceptions do occur. Long ago when I learned of vacuum bleeding, I had experience sealing threads in plumbing, on the job. I asked myself, "What keeps the vacuum from sucking air down the threads and into my vacuum line"? The likelihood of a leak is less with new parts, more with older, possibly corroded parts. I decided to apply Permatex #2 (non hardening) to the bleeder threads. Not a guarantee to stop air intrusion, but it also reduces the likelihood of future bleeder seizing from corrosion. That has worked for me. No matter what one sees or does not see in the bleed hose, it is the firmness of the pedal that determines when you have succeeded. My OCD nature leads me to perform a brief pedal bleed after vacuum bleeding, just to be sure.
jim