Before anyone says "Bleed 'em again", let me explain.

I bought a used master cylinder and rebuilt it so everything inside of it is in great shape.

It bolted on w/o issue aside from slightly bending the lines to the proportioning valve slightly.

I bench bled the master cylinder and had no issues.

After bleeding the brakes, I did find that my driver side caliper is stuck and won't bleed (which I already guessed based on the fact that the brakes pull hard to the right in a panic stop). Everything else bled fine and the fluid is new.

Understanding that I do have an issue with the caliper (which was there before the M/C swap), I am noticing that my pedal feels dead/nothing until its depressed about 2" down and then braking feels "ok". Should the new master cylinder make the pedal go down that much further before it engages the brakes? I will be swapping and bleeding the new caliper tomorrow, but I don't think this will fix the current issue.

Those of you that have switched to the LS1 master cylinder, have you had this same issue? Ideas?

 

fix the caliper issues, and you may have to bench bleed it again, sounds like there is still air in the master

 

I've bled and bled my brakes and have a similar problem with the LS1 master(stock 3rd gen brakes up front and ls1's on rear). It feels like my brakes wont even lock up but I don't know what caused the change, the LS1 master or the rear LS1 calipers. Hoping to upgrade to brembos soon and find the culprit at the same time.

 

WTH is an ls1 master? anyhoo if it's a corvette master or similar to one note that the bore is a lot smaller than the stock unit meaning you will have more pedal travel

 

LS1 powered vehicle 98-02 Fbody master cylinder.

 

Changed out the D/S caliper today and bled it - Still the same problem, although the brakes feel slightly better, but the pedal still "SHhhhhs" for about 2 inches before there is any brake engagement. I can't tell exactly where it'd be "hitting the floor", but it feels like its going down as far as it can (w/o hitting the carpet).

Oddly enough though, I still have a problem somewhere, because my car is still pulling to the right under hard stops - I thought it was because my D/S caliper was messed up, but after bleeding the entire system, the car still pulls.

First: Any idea what's causing the low pedal brake engagement?

Second: Any idea why the car is still pulling to the right since everything has been bled and the new D/S caliper installed?

 

My first guess on the pulling would be the brake line. The rubber hoses are known for collapsing. I would double check the drivers side brake line.

The low pedal engagement seems like in the line, even though you have bled the brakes multiple times.

 

Could be - I'll probably pick some new lines up tomorrow. As for the brakes - THEY SUCK RIGHT NOW! I had to slam on them earlier tonight and thought for sure I was going to hit a Cadillac because I couldn't stop! I've gotta get this fixed.

 

Well, I bought 2 new brake hoses and a new P/S caliper today and just finished installing them. The car pulls straight now, no more pulling to the right! The pedal feels even lower now than it did before - I bled each side like 6-7 times! The braking performance seems about average - as average as a small front disc and rear drum brake setup can feel, but I still have no real pedal feel to speak of. Any ideas?!? I'd really hate to switch back to the 3rdgen master, but damn, this doesn't seem to be giving me any positive results.

 

define no pedal feel. Does the pedal get hard, feels like it bottoms out quickly and has little travel, or is it really mushy and can be pushed all the way to the floor.

 

Basically has no resistance until its about 1"-1.5" from the floor (or wherever its designed to 'stop').

The pedal basically doesn't feel like anything until it gets very close to the stop (or floor) and then is pretty firm.

Its not spongy or anything until the brakes actually engage, its like there's nothing there.

 

I'm having the same problem, but with C5 fronts and LS1 rears. My brake light stays on which for sure means there is still air in the system. I'll keep my attention on this thread as it may help me, too.

 

I assume you're running the LS1 m/c?

 

Ahh, I wasn't clear on this, but no, I am not. Just a stock replacement. I do need to change the prop valve, too. that can be part of my problem, as well.