And Now The Brakes...

[SoFlStang]

Well this car is definately an interesting project Today I went out to bleed the brakes, as the pedal feels squishy. With the car off, I get a pretty stiff pedal, but once I turn the car on, the pedal goes soft and begins to drop to the floor. I bled the brakes, but its still squishy when the car is running. I have to press the brakes more then halfway to get them to engage and stop the car. Testing them to make sure I could make a quick stop, I could, but I had to press the brakes to the floor. Any ideas on what is going on, why can't I have a solid pedal when the engine is on?

Also, I noticed I had what appeared to be a leaking rear caliper. I was told by the previous owner it had a 95 mustang rear end on it. Well, the calipers have a part number on them which appear to link back to a lincoln mark vii. So now I am not sure about anything else the previous owner told me. I did research that it seems fairly common to have that rear in the mustang though. Turns out the caliper is ok, it was leaking around the banjo bolt, so I replaced the washers and all appears good.

Well as always, any help is greatly appreciated.

 

[boostfrk]

If your pedal is sinking to the floor when the car is running it sounds like it could be the master cylinder going out.

 

[SoFlStang]

Thanks for the reply. I will pick one up tomorrow and install it monday. I will post if that fixed the problem. Thanks again.

 

[mikestang63]

First thing, do the squishy pedal was in part because of the leak which you know.

If the PO switched the rear brakes to discs and kept the stock master, that can often lead to a squishy pedal. You may need to swap out to a MC with a smaller diameter bore to compensate. I believe the 93 Cobra is smaller but others can confirm.

Are you sure he didn't swap in a lincoln rear end and breaks? Do the rear wheels stick out a little past the fender.

 

[2000xp8]

First thing, do the squishy pedal was in part because of the leak which you know.

If the PO switched the rear brakes to discs and kept the stock master, that can often lead to a squishy pedal. You may need to swap out to a MC with a smaller diameter bore to compensate. I believe the 93 Cobra is smaller but others can confirm.

Are you sure he didn't swap in a lincoln rear end and breaks? Do the rear wheels stick out a little past the fender.

Agreed.

Check to see which MC you have.
A rear disc conversion requires a 94/95 mc or a 93 cobra.
It also requires a port conversion and an adjustable proportianing valve.

So running out to the store to get another stock one is definitely not the answer.

 

[SoFlStang]

I am guessing they put in a lincoln rear end, since the part number on the rear caliper came back to an 87 lincoln mark vii. It appears the mc is the stock one. So since I have a disc rear end, I should get a 94/95 mustang mc? I went out and bought the stock one this morning before reading the new replies. Will the 94/95 bolt right up or is there more work to be done? Thanks

 

[SoFlStang]

I just went and matched the mc in the car to the mc I purchased and they are the same. So they did the 5 lug swap and didnt change the mc. So it looks like I will need to do the port conversion too. Can I purchase the parts for that at the part store?

 

[mikestang63]

This is what I used last time. Not the cheapest but by far the easiest IMO.

http://www.maximummotorsports.com/s...nfo&cPath=49_140_517_520_536&products_id=1264

 

[SoFlStang]

Ok, just so I am clear on what I need to do. I am pretty sure I have the lincoln rear, I am 99% positive I have the lincoln calipers iand 100% positive I have 4 wheel disc brakes So, can I use a 94/95 gt master cylinder and the 3-2 conversion kit from Maximum? If so, I will order the kit tonight and pick up the mc at the parts store tomorrow. Thanks again guys for all the help, without you I would be lost on this project. I've already learned a bunch and wish I knew more before I got this one.

 

[mikestang63]

Here is all you will ever need to know about Fox body brakes

http://home.comcast.net/~mjbobbitt/mustang/page1.html

 

[Mustang5L5]

First off...you NEED to identify which brakes you do have on your car.

The Lincoln rear disks are pretty large at 54MM, so you need an MC large enough to supply enough fluid for them with a larger than stock bore.

What front brakes do you have here? If the stock 60mm calipers, you might be able to get away with a 94-95 GT master cylinder. If they are the lincoln 73mm calipers, your only MC choice is the 84-86 SVO 1 1/8" bore master cylinder.

If you have SN95 front brakes...well that's a whole different ball game.

But before buying anything you really need to make sure of what you have and buy correctly matched parts. Too many brake setups out there are done "just ok" with mismatched parts vs getting the parts that actually work with the system. There is a little bit of engineering thought behind master cylinder bore sizes vs piston area at the calipers.

 

[David Pepiton]

you will also want a adjustable proportioning valve for the rear.

 

[SoFlStang]

Thanks for the info. I am picking up the wilwood adjustable proportioning valve on Friday. I have been reading like crazy on the 3-2 conversion, and I really like the one on mjbobbits site. Seems like I could make one easily, just not sure on the size for the 't' and adapter, I've read 3/16 and also 1/8, I believe but don't quote me on that. If anyone has built one, or knows the sizes, could you share the sizes?

Edit: So I found some other threads where the stock proportioning valve was removed, a tee was used for the three lines and the adjustable proportioning valve was used to connect the two lines, all of this was placed where the stock proportioning valve is now. I like this idea as it reduces clutter, appears to separate the system, and from what I read works well. Any input on this type of setup?

 

[Mustang5L5]

It works fine, but you lose the safety feature of the shuttle valve located inside the combination valve.

Some will argue it doesn't really work that well anyway.

 

[SoFlStang]

Well I have completed the installation of the new master cylinder, went with a 94 GT. I removed the stock proportioning valve, used a brass tee for the front lines and an adjustable proportioning valve for the rears. I have to say, after doing the change, if I had to change it on another Fox, I would DEFINATELY buy the kit for the 3-2 conversion. The cutting and flaring and the hunting down of the adapters to make it all fit together was not worth the money saved from purchasing the kit and the plug for the stock valve. Installing the new master was simple, bolted right up. The brakes are 100% better now, nice strong brakes. Thanks again to everyone who offered their input and advice.