soft pedal after rear disc conversion.

Topic: soft pedal after rear disc conversion. (Read 2455 times) previous topic - next topic

soft pedal after rear disc conversion.

May 10, 2006, 02:13:54 PM

well, I need all your help again. I installed an 87 tc rearend with disk brakes in my 88 sport over the last two days. my father and I bled the rear brakes only untill there was no air, and the pedal was firmer. when I started it up, the brakes were SOFT. the pedal went a good 75% before they started to engage. drove it a bit, then bled them again. they firmed up and then went soft again after starting it. what could cause this?
thanks for the help.

soft pedal after rear disc conversion.

Reply #1 – May 10, 2006, 02:17:03 PM

Did you do anything with the stock brake proportioning valve?

soft pedal after rear disc conversion.

Reply #2 – May 10, 2006, 02:19:28 PM

The MC is probably a bit small for your set-up now too.

soft pedal after rear disc conversion.

Reply #3 – May 10, 2006, 02:24:16 PM

well, to tell you the truth, I couldnt find the stock prop valve, I dont think mine had/ has one. I put a jegs adjustable prop valve in line to the rear brakes right under the metering(?) block. ( that thing right under the m/c)
thanks

soft pedal after rear disc conversion.

Reply #4 – May 10, 2006, 02:25:27 PM

That IS the stock proportioning valve.....

soft pedal after rear disc conversion.

Reply #5 – May 10, 2006, 02:30:37 PM

so, what do I do with it? it feeds the front as well as the rear, and isnt that where the piston is?

soft pedal after rear disc conversion.

Reply #6 – May 10, 2006, 02:37:41 PM

You did almost everything correctly. :)

The stock metering (prop) valve has to be gutted. Right now it wants to meter the fluid just as it does with a stock disc/drum setup. You need more fluid flow to the rear. The adjustable prop valve will do that, but first you have to gut the stock one.

You need to get a special fixed plug from Ford Racing, p/n M-2450-A. Then, remove the plug from the front (faces front of the car), gut the plunger and spring, put in the new plug, bleed the brakes, and that should help things significantly.

soft pedal after rear disc conversion.

Reply #7 – May 10, 2006, 02:42:42 PM

-tastic. that explains alot. thanks guys. I dont know if it means anything but the brake pedal firms up if i pump'em.
if im making very little sense, its because im doing all this while running a temp, ugh

soft pedal after rear disc conversion.

Reply #8 – May 10, 2006, 02:42:44 PM

You may still have a low pedal when all said and done though. It is possible though that you probably just could not get enough flow to the rear to bleed them properly

soft pedal after rear disc conversion.

Reply #9 – May 10, 2006, 06:16:00 PM

Ok so basically you are turning the stock prop valve into a "distribution" block?

soft pedal after rear disc conversion.

Reply #10 – May 11, 2006, 09:24:07 AM

I run a tc rear all stock no mods (for about 10 years now) and the pedel is fine. You really have to bleed the out of it. I also bleed all 4 wheels not just the back

soft pedal after rear disc conversion.

Reply #11 – May 11, 2006, 12:18:49 PM

I still have to wonder how some of you guys can convert to rear disc and still have a "good" pedal on the factory master cylinder...the stock MC bore size is marginal at best for four wheel disc.

soft pedal after rear disc conversion.

Reply #12 – June 10, 2006, 12:03:13 PM

I remember reading somewhere that the 86 and 87 Turbo Coupes had a smaller master cylinder than the 88. I just finished putting in a four wheel disc into my 88 LX and used a 88 proportioning valve. I posted a question as to the part number to see if it was indeed from a Turbo Coupe.

soft pedal after rear disc conversion.

Reply #13 – June 28, 2006, 05:26:52 PM

Weren't all 87-88 T-coupes ABS brakes?

soft pedal after rear disc conversion.

Reply #14 – June 28, 2006, 06:30:55 PM

yessir, 4 wheel ABS....but the ABS will be non-functional on a TC rear swap...
It'd be way too much of a hassle to get it to work...and it's somewhat problematic anyway, IIRC-i might be talkin' :bs: about that though.
I've got a TC rear I'd like to put in mine, but some ass-pirate :flame: cut the e-brake cables some time long before i got my parts TC...