Pulling my hair out!

[Backnzagain]

Hi everyone, I'm new to the forums and have been searching for an answer to my problem. So far all the advice I've read, I've already tried. Here's what's going on. I replaced the master brake cylinder and bled the system. I started with mc first, then to the calipers furthest away first. I have pressure for the rear brakes, calipers and at the mc. But on the front I can't get pressure at the mc or the calipers. The only thing I didn't do was bench bleed the mc before I put it on. And from what I've read I've got a 50/50 chance it'll help if I take it off and redo it. Does anyone have any more ideas? I'm not a super mechanic but I do alright, this has really got me stumped. I did the exact same job on a zx I had once-upon a time and had no problems at all. Throw some "did you do this?" at me and I don't care how simple it might be, I'll try anything at this point. I'm about to buy the book "Brakes for dummies". Help!

[Darrel]

Did you replace the calipers? If so are the bleed screws on top? You don't need to bench bleed the z/zx master cylinders. They have the bleed screws already and can run a hose from there to the resivours.

What part of denver are you in?

yr and model z?

[Backnzagain]

Hey Darrel, I replaced the front right caliper, the left is still good. Bleeder screws are on top. I'm in Aurora, almost Denver actually. I'm just about 10 blocks east of the line. It's a '78 but manufacture is November of '77 if that matters.

[Darrel]

Are you getting fluid to the calipers when you bleed them?

denver/aurora line, that's a big line. cross streets?

I'm in broomfield.

[Backnzagain]

Cool, I'm almost in the Stapleton area between Colfax and 17th, Havana and Syracuse, I think are the next sort of major streets. I'm getting fluid out of the calipers and the mc, but just no pressure. It just kinda oozes out, like its in no hurry. The back brakes are fine, pressure at the wheels, pressure at the mc.

[Darrel]

could be a bad master cylinder. Where did you get it?

[Backnzagain]

I got it off of ebay, new in the box Nabco. What are the odds its bad? Other than it not working right, any other way to test it?

[Darrel]

You can check to see if is leaking out the back and into or through the firewall. There is a thread on hybridz about a reaction disc in the booster that might have fallen out of place, I'm not sure of the symptoms if that is the case.

[=Resurected280=]

I got a bad MC (rebuilt) from a local parts store, but, I didnt bench bleed it either (a seal in the MC got flipped backwards and ripped when they assembled it I found out upon further inspection). I must have tried to bleed my brakes for 3 hours and got absolutely nowhere. My MC was a Nabco as well. I would try one from a parts store and see if it works if you dont see anything wrong with the system, from my memory theyre not too much money for a rebuilt one.

Just a suggestion, good luck =)

[Backnzagain]

Yikes! I read up on that. It's a big fat maybe. I didn't notice any leaks, and I've been watching for them. But I haven't checked through the firewall. I have to pack it in for today, but I have all of tomorrow to take another stab at it. Thanks for the pointers, I'll be back on here if I come up empty again.

[sideshowbob]

Also check the lines, I had one rust through underneath one of the clamps that holds it to the frame. Doesn't sound as if this is your problem, but it's worth a check. I also had the fluid leaking into the firewall (and into the engine through the vacuum line) from a bad MC.

[beandip]

You can check to see if is leaking out the back and into or through the firewall. There is a thread on hybridz about a reaction disc in the booster that might have fallen out of place, I'm not sure of the symptoms if that is the case.

If you remove or pull the rod that extends out of the vacuum booster the reaction disk will likely drop out of position. If this happens the peddle will go to the floor when the brakes are applied . So when you remove the master cylinder , don't mess with the rod. I was lucky and was able to reposition the disk in place with out taking the booster all apart . The problem 280 is having does not sound like the reaction disk situation. Sounds more like the Master is faulty. Try bleeding the MC once more . Gary