Hey guys,

I've got a 92 regular brake coupe. No big brake option on this car.

Recently, the brakes have started to behave strangly. The pedal is suddenly very soft. The travel is longer as well. The pedal won't pump up. The brakes still work and the car stops just as quickly as before (which was horrible)

In the last year I've replaced:
Master cylinder (with one from EBAY...questionable)
vacuum booster (with the metal one from that hotrod website)
brake fluid
pads (Hawk HPS)
rotors (slotted)

I've bled the system twice. There is no fluid leaks that I have found.

The change in pedal feel was very sudden - like something snapped. Any idea where to look first?

Is there anything that can pop in the ABS module? Is my master cylinder bad (OMG are those expensive )

 

The only times I'v had a brake pedal go soft on me was when the master cyl went...or if I boiled the fluid while on the track....getting into too many corners too hot and standing on the brakes.

A mis-match of brake fluid can lead to a long pedal also

 

The brake fluid is DOT 4. Replaced it all...

 

Thats one trouble idea down

 

I have a similar problem and have done similar things with no change. Have my own posts going to. My pedal is soft also and can go full travel. I can just rally feel it start to grab when it gets to floor. I assume you bench bled the master before installation and then cracked the fittings for final air evacuation. I have done basically everything you have except for the booster (mine is OK with tons of power).

When your foot goes down, the fluid has to go somewhere (my theory) and that is what has to be fixed. Fluid does not compress and pistons in the calipers only move a small amount.

Just this week I have ordered SS flex brake lines. I don’t see a flex line problem but that might not mean anything. It is last on the list other than the ABS pump assembly which I also bought one this week on Ebay. I hope the flex lines fixes me, I do not want to change the ABS.

I have flushed, power bleed my system, back bled and all the other normal bleeding routines. If there was that much air in the system I would have got some of it out but there has been no change at all. So I am moving forward the next level. I would suppose it is possible you could have a bad flex line also.

I was always worried about the ABS doing something strange that I couldn’t see or troubleshoot normally. There are seals in the ABS so I have been told. A shop asked me if I had any ABS codes (module 9), you just might want to check yours.

If you pedal wont pump up and does not sink when you hold your foot on it, then the master is probably OK, same as me, I got a GM part.

Will let you know if I make progress.

 

What about the brake bias spring? Have you replaced it?

A brake bias spring will transfer some braking power to the rear (the stock setup is forward bias for understeer and safety) which does work at the limit... but be careful setting up in a corner after hard braking.

I've heard many C4 owners rave about the differing swapping out the brake bias spring made in their cars.

 

I have replaced the bias spring with the performance one. It made a little bit of difference - I wouldn't exactly "rave" about it.

The brakes on this car have been terrible since the word go.... I'm going to bleed the brakes this weekend before I start buying expensive parts.

 

...i had a master cylinder that was so "out of it", i could not even bench bleed it!...it would not build pressure at all!

 

Start with the easiest. Do a complete brake fluid flush and replace with a good synthetic like Valvoline. If that doesn't give a positive results, purchase a new master cylinder.

 

Did a brake flush with valvoline synthetic. no bubbles. no change. I think it's the master. I even tried extending the push rod from the end of the booster a couple turns... no difference.

Anyone tried the rebuilt units at Napa? it's like $100 vs the $350 over at fred beans.

 

Check out this Ebay site for a master, it may be of interest to you. I got mine here and have done other business with her also.


http://cgi.ebay.com/ebaymotors/92-93...temZ8071062138


I just put SS flex brake line on this weekend with no change in performance. I am now looking at the ABS real hard. As you ask, can the ABS pop. I don’t know yet but focusing on that now. It will be a very strange fix if it turns out to be it.
I hope if you change your master again you have better luck than me and get it fixed.

 

as with anything through ebay, let the buyer beware...i have had relatively good luck there.....

 

I've done business with this person a few times. Great products and great prices.

 

.......for the record, i am not casting any dispersions by my last statement.....

 

We're all consenting adults, here. You pays your money, you takes your chances...

 

.....yeah buddy!........

 

Yup - I'm replacing an ebay purchase from last year. I am that beware buyer. No thanks!

I'm looking at a rebuilt lifetime guarantee unit from Kragen. If it don't work - then another one for free....

 

......sometimes when you pay a little more, ya pay a little less (in frustration and anger)!

 

Hi,
Always thought that when the pedal keeps going down, when at a stop, bad master. Hope that is not the case. Also tired of buying stuff at NAPA. Bought plug wires last week, one too short. A friend bought a rear end, slightly too short. Ruined other parts. Other stories also. The end result is save money and buy good stuff in the first place. No dealer connections, just experience. Say no to NAPA.
All the best, lbreen

 

......could be bad master of just a lot of air in line (or major leak!)....