brake problem, what gives? UPDATED 2

[Butter]

The last 4 rebuilt MC's I installed were bad. Always had to take them apart. 3 had seals installed carelessly (lips were bent back), and 1 was full of rust.

Taking the plugs off after bench bleeding does not negate what you just did. As long as the resevoir is filled and you don't take too long to install the lines, gravity will keep the air out.

[Az4u2c]

So, after trying the 2nd master cylinder from Victoria British (or whatever they are now) my brakes were still shit. So, thinking I wasn't getting them bled, I took it to midas for a bleed/flush. Now they are actually WORSE. I should have known better than to let those bunch of dropouts touch my car. More importantly I still have a genuinely shitty brake feel. Pedal to floor long before anything resembling lockup. What gives? No leaking fluid, no visibly expanding lines, what the hell? Should I try a master from Nissan and see how that goes? That the hell, I'm stumped... :x

[2+2turbo]

you loosing brake fluid ?? what have you not looked at as of yet ? .

is the reservoir clean???

[Az4u2c]

2+2turbo wrote: you loosing brake fluid ?? what have you not looked at as of yet ? .

is the reservoir clean???

Zero loss of fluid. No visible leaks. reservoir is brand new for the 2nd time now. My only conclusion is that these masters suck and I need a Nissan one, but that seams fishy to me. I'll go bitch to Midas tomorrow and see how they feel.

Anybody successfully used a VB master?

[SATAN]

If you are going to get another master cylinder, I would suggest getting a z32 turbo MC I belive the 91-92's??? They are the 1 1/16" MC's. I hear they give a much firmer feel. This is normally with the TT calipers though. Maybe it will help for yours too though. You do have to modify them a little. But its not too hard.

[Az4u2c]

SATAN wrote: If you are going to get another master cylinder, I would suggest getting a z32 turbo MC I belive the 91-92's??? They are the 1 1/16" MC's. I hear they give a much firmer feel. This is normally with the TT calipers though. Maybe it will help for yours too though. You do have to modify them a little. But its not too hard.

I saw a thread somewhere a while back that explained what to do, where was that?

[Az4u2c]

Is there any possibility the brake booster is the source of my flexing/spongyness?

I inspected all four corners for caliper/line flexing...nothing. No air in the system, professionally force-bled.

I did a test. I took the master off the booster, bent the hardlines enough so i could get a screwdriver in there. I can only move the piston in the master about 1/8 inch pushing as hard as i can. So i concluded my brakes are solid from the master forward. The problem must lie between my foot and the Master. The only thing in between is the pedal (not bending, mounted solidly) and the booster/servo. I don't know what is in a servo, could this possibly be the source of my 3 month micky-mouse hunt for the problem?

The booster works, the pedal is not high-effort like it is with no vacuum to it (engine off), however the pedal is really spongy and never builds up any firm feel.

[Guest]

im kind of having the same probelm after installing twin piston calipers/lines/rotors/hubs off an 87. . . everything worked great before i did the swap so it cant be the MC or booster.

[Az4u2c]

Dick wrote: im kind of having the same probelm after installing twin piston calipers/lines/rotors/hubs off an 87. . . everything worked great before i did the swap so it cant be the MC or booster.

Yeah bingo, i feel you. I swapped and now everything has gone all to hell. Nothing seams to help...makes me want to strangle kittens or something. :evil:

[SATAN]

[quote]Az4u2c wrote:

If you are going to get another master cylinder, I would suggest getting a z32 turbo MC I belive the 91-92's??? They are the 1 1/16" MC's. I hear they give a much firmer feel. This is normally with the TT calipers though. Maybe it will help for yours too though. You do have to modify them a little. But its not too hard.
I saw a thread somewhere a while back that explained what to do, where was that?

This is one of them
http://www.z31performance.com/forum/vie ... r+cylinder

[Guest]

how about adjusting the height of the brake pedal?

[Az4u2c]

Dick wrote: how about adjusting the height of the brake pedal?

It's adjusted. A couple mm of free travel as per FSM. Even if that were wrong it doesn't explain the bucket-of-lard pedal feel i've got. Even with the car off I can mash the pedal halfway down even after several pumps. Normally you just about can't move the pedal at all without the booster, much less kill it to the floor on the first try.

[Atlantaz]

what did you do to cause this problem...... new calipers.... check there.

might be an internal problem.

[Az4u2c]

Atlantaz wrote: what did you do to cause this problem...... new calipers.... check there.

might be an internal problem.

Inspected yesterday. Nothing out of the ordinary. both calipers grab and release like they are supposed to. Pads/rotors appear normal.

[Firehawk]

Dick wrote: im kind of having the same probelm after installing twin piston calipers/lines/rotors/hubs off an 87. . . everything worked great before i did the swap so it cant be the MC or booster.

Sure it can. I had it happen. Doesn't make sence, but a new master fixed the problem. Something like this was discussed in another thread. Lots of rebuilt masters are out of spec and either doa or don't last long.