View Full Version : Power Brake Retrofit Mk2 MkII
Spartan1510
08-12-2020, 02:48 PM
Hello everyone, I just purchased an Mk2 from a friend. Car is in great condition, and I've already modified the pedals with a pedal bender and Russ Thompson pedal kit.
The car does NOT stop well. I've been looking into the concept of converting to power brakes, but most of the posts I've found are when the car has the body off (either during the build, or a rebuild). These seems like it may be a substantially unpleasant task unless I take the body off. Can anyone share positive or negative advice on converting to power brakes while keeping the body on?
Car has an '89 Mustang donor.
And if not power brakes, then what would be the next best upgrade for stopping power? (I should note that it has 4-lug halibrands and I would like to keep the current wheels)
Thank you in advance!
Grant
Jeff Kleiner
08-12-2020, 04:18 PM
Was the modification done to change the pivot point of the brake pedal? If it was not done the braking will be poor.
Jeff
michael everson
08-12-2020, 04:20 PM
Do you know if the pedal mod was done? If the pedal is bolted in the top hole on the foot box then it hasnt been done. If its about 1.5 inches down then it has been done.
If not then I would convert to power brakes. I do them all the time with the body on. Its a lot harder but can be done. If the pedal mod has been done you will also need to change the pedal before doing the upgrade. This can be nearly as hard as doing the whole upgrade. Still can be done though. It takes me a full 8 hour day to do the whole thing.
If you have an Oreilly auto parts near you, here are the parts you will need.
10-2854 master cylinder
54-73207 87-93 booster
BLF33B adapter for brake line
BLF31B adapter for brake line
You will also need a booster spacer from www.replicaparts..com
you will need a remote reservior. Most people use a remote from a 99 Mercury Villager.(junk yards are full of them)
You will need to do a frame mod to clear the booster. This requires you to cut a 6 or 7 inch section out of the 3/4 that is near the booster. I just bolt a longer peice to the outside of the 3/4 tube to reconnect it.
Thats about it. Its all doable.
mike
Rdone585
08-12-2020, 08:00 PM
Welcome to the forum. We hope to best guide you on how to enjoy your new car safely.
Do you have a firm pedal and still poor braking? It's possible, you could change the brake pads and that might be enough.
- What brakes are on the car?
- Disk on front and rear?
- What Master Cylinder in installed?
- Is the peal mod done as previously asked?
- Are the flexible lines to the calipers in good condition?
While converting to power brakes could solve your problem, it's not necessary to get good braking. I've run manual brakes for 18 years including on the track. The right pads can make all the difference. The answers to the above questions could help us best guide your choices.
Robert
Spartan1510
08-12-2020, 08:52 PM
GREAT responses and thank you! Here’s what I know so far....I took some pictures of the brake pedal at the top. It’s hard to see, but appears to be shortened and welded? It’s dark but I can look at it again in the daylight in a few days.
The pedal is soft. But I am aware of two problems as it sits. The front passenger caliper appears to have seized, and the rear passenger is leaking brake fluid. So those are the absolute first priority to get fixed.
I used a pedal bender and installed the Russ Thompson pedals. After three days, my body has finally forgiven me for what I made it do to reach the pedal assembly..... If the brake pedal needs to be replaced......My appetite is leaning towards options that keep the current brake pedal..... but I’m wide open to options!
Spartan1510
08-12-2020, 08:57 PM
I didn’t answer all the questions....
‘89 Mustang rotors on the front
‘89 Mustang drums on the back
I just changed mine over to power brakes, i also have 89 mustang donor brakes, it was not that bad with body on , it makes a big differance in stopping, wish i had done it years ago!
If you want some information just pm me and we can set a chat up sometime.
michael everson
08-13-2020, 05:13 AM
based on your pics, you have a modified pedal. that's good news if your going to keep manual brakes. Bad news if you want power. I have converted a lot of cars to power brakes. Not one person ever said they didn't like it. Most said they wish they had done it sooner. You can replace the caliper and fix the leak in the back and still have marginal brakes. I just did a conversion on a car with your exact setup. Stopping power was horrible. Bite the bullet and do the conversion or find someone that can. I don't know how many options for performance pads there are for your brakes, but I guess it cant hurt to try.
Mike
CraigS
08-13-2020, 07:06 AM
A- Stay w/ manual brakes.#1, get rid of that junction block. It had 2 purposes;1- turn on a warning light if half of the system wasn't building pressure, 2- keep the rear brakes from locking. The second one is the killer as all it can do is reduce rear brake function which is NOT what you want on an FFR. You can leave it in place but gut the rear brake portion.
https://live.staticflickr.com/65535/50221692991_8bb1a2578c_z.jpg (https://flic.kr/p/2jvViCt)BrakeControlValvecopy (https://flic.kr/p/2jvViCt) by craig stuard (https://www.flickr.com/photos/152454123@N04/), on Flickr
There used to be a cap you could buy w/o the hole but hard to find. I pulled the cap, drilled the hole out a bit and got a small crew, 2 aluminum washers, and a lock nut to plug the hole and reinstalled the cap. #2, I have never been able to find brake shoes w/ better lining so upgrading to rear discs will help because you can then get better pads. I used to run Hawk HPS front and HP+ rear to help get more rear brake.
B- going to power you would need to change the pedal. On mine the bolt that the pedal pivots on had it's head on the left side. I cut a flap into the aluminum so I could get the bolt out. After installing the new pedal I bent the flap back and sealed w/ silicone. If you use the Whitbys kit to install the booster be sure to get a couple of short pieces of solid square rod to fit inside the tubing so you can tighten the bolts w/o collapsing the tubes.
Spartan1510
08-13-2020, 08:37 AM
Appreciate all of the responses!
I think I'm going to start with "fixing" the issues with the front caliper and rear leak so that it's road worthy, and take some more looks to see how difficult it would be to change that pedal out.
For CraigS, where did you cut the aluminum to get to the pedal? I'm thinking that a new piece of aluminum could be cut and riveted to go over the hole and look like it was meant to be there...
michael everson
08-13-2020, 11:23 AM
Spartan, where are you from?
Mike
Spartan1510
08-13-2020, 12:17 PM
Home is Michigan. My wife and I are both Michigan State University Spartan Alums. For the past 7 years, we have lived in a northern suburb of Dallas, TX.
Rdone585
08-13-2020, 02:45 PM
I'll be visiting family near Lavon in November. If you're still working on or trying to figure out what approach you want for brakes I'd be glad to come over and lend a hand. I may even have some extra Mustang GT calipers hidden in my garage somewhere with Hawk HP+ pads. I'm sure you'll be happy going with power brakes but manual brakes can be made to work very well if done right. I also feel that manual brakes also give me more of a feel for what's happening on the pavement. I've seen lots of drivers flat spot tires on the track. Most of them were running power brake setups and had trouble balancing the front and rear. Once tires are flat spotted the car feels like it always on a bumpy road all the time. Up here in WI (and MI) that might be a normal thing though :rolleyes:.
Dont forget if you change to power brakes you need to change the brake pedal for a stock length one in the top mounting holes.
Norm B
08-13-2020, 05:38 PM
Dont forget if you change to power brakes you need to change the brake pedal for a stock length one in the top mounting holes.
That was the not so fun part when I converted to power brakes on my car.
I hear that Norm, that and drilling the hole bigger in the front of the footbox were the toughest parts . I ended up useing a heavy piece of electrical wire to hold the pedal from above while i got the bolt in.
CraigS
08-15-2020, 06:58 AM
I started to slide the bolt out toward the aluminum so I could see where to cut the hole. It was ugly. It's hard enough to see up there and not fun having the debris falling in my face. I ended up w/ goggles over my eyes that seal tightly and then a big shield to deflect more away from my face.
Luckily on mine its a mk4 so it has the opening already cut in the top of the driver footbox !
mcwho
10-26-2020, 09:45 AM
Do you know if the pedal mod was done? If the pedla is bolted in the top hole on the foot box then it hasnt been done. If its about 1.5 inches down then it has been done.
If not then I would convert to power brakes. I do them all the time with the body on. Its a lot harder but can be done. If the pedal mod has been done you will also need to change the pedal before doing the upgrade. This can be nearly as hard as doing the whole upgrade. Still can be done though. It takes me a full 8 hour day to do the whole thing.
If you have an Oreilly auto aprts near you, hear are the parts you will need.
10-2854 master cylinder
54-73207 87-93 booster
BLF33B adapter for brake line
BLF31B adapter for brake line
You will also need a booster spacer from www.replicaparts..com
you will need a remote reservior. Most people use a remote from a 99 Mercury Villager.(junk yards are full of them)
You will need to do a frame mod to clear the booster. This requires you to cut a 6 or 7 inch section out of the 3/4 that is near the booster. I just bolt a longer peice to the outside of the 3/4 tube to reconnect it.
Thats about it. Its all doable.
mike
michael,
is this booster perhaps the same as the one supplied by the Whitbys Poser brake kit. I am looking for the specs on that just for reference.
Bob
Is it possible to go to a master with a smaller diameter piston?
michael everson
10-27-2020, 05:25 AM
Bob. Yes 87-93 Mustang
Mike
Richard Oben
10-27-2020, 08:17 AM
Porterfield, Carbotech, Hawk and others make pads for those front calipers. This makes a LOT bigger difference than most people think it will. Swapping to discs in the rear is an option but not something that needs to be done yet (www.northracecars.com) when it is time. With the Stock MC the manual pedal etc the brakes are just OK. Swapping to the earlier 7/8 bore will help on the MC. HTH, Richard.
Purple Venom
10-27-2020, 07:47 PM
Check out this company - http://www.abspowerbrake.com/ - Electric power brakes. Their master cylinder has a 1 1/8" bore, fluid is gravity fed from the reservoir down to the motor/accumulator. I had a lot of issues at first, but determined it was due to heat from the headers. Since I've re-located it away from the headers, no issues. Brake pedal effort is similar to your daily driver.
Joe Campbell
11-02-2020, 02:15 PM
Do you know if the pedal mod was done? If the pedal is bolted in the top hole on the foot box then it hasnt been done. If its about 1.5 inches down then it has been done.
If not then I would convert to power brakes. I do them all the time with the body on. Its a lot harder but can be done. If the pedal mod has been done you will also need to change the pedal before doing the upgrade. This can be nearly as hard as doing the whole upgrade. Still can be done though. It takes me a full 8 hour day to do the whole thing.
If you have an Oreilly auto parts near you, here are the parts you will need.
10-2854 master cylinder
54-73207 87-93 booster
BLF33B adapter for brake line
BLF31B adapter for brake line
You will also need a booster spacer from www.replicaparts..com
you will need a remote reservior. Most people use a remote from a 99 Mercury Villager.(junk yards are full of them)
You will need to do a frame mod to clear the booster. This requires you to cut a 6 or 7 inch section out of the 3/4 that is near the booster. I just bolt a longer peice to the outside of the 3/4 tube to reconnect it.
Thats about it. Its all doable.
mike
Mike, what year is that MC from?
michael everson
11-02-2020, 04:20 PM
1995 Mustang Cobra
Mike
Joe Campbell
11-24-2020, 11:32 PM
Anyone know a part number for the plastic nozzle/caps that fit in the MC reservoir ports (that I connect my remote reservoirs to)?
I used aluminum ports that were threaded to take an elbow for hoses to the remote reservoirs , if you need I can dig up his information for you.
milehighjason
12-22-2020, 01:08 PM
I recently picked up a Mk 2 with a leaky master cylinder. After some research I think it's got a Cherokee MC. I'd like to replace with a 93 Cobra model (I have power brakes). I could use some more details on the elbows that fit into the master cylinder to run to the remote reservoir. If I get the elbows from the Villager what would I do for a reservoir? Do most people buy universal reservoirs and fabricate what is needed to make them work? Thanks very much!
jts359
09-01-2022, 03:34 PM
Hi Did you have to notch the Vertical 3/4" square stock that supports the steering shaft ? In order to make room for the front brake hydraulic tubing , Thanks Ed