Brake Issues. Ugh.

[moozieman]

Spent some time working on my 1977 280z last night and was almost ready to drive it. Just had to tie off some loose ends and make sure that the brakes were operational. But that's the thing... the brakes DONT work. I can't seem to get any response from one of the front brake calipers. I can't collapse the pistons. I attempted to use a C clamp but to no avail. I ended up giving up on that and moved on to some other brake components. I recently installed a new master brake cylinder for the first time and it went reasonably smoothly. I filled the reservoir and began the process of bleeding the brakes. Only one of them bled. There's nothing coming out of the rears. The bleeding nut on the MC for the rears didn't release anything. Nor did the nut on the ceased caliper. After working on it for a while, the whole thing became a mess of stripped brake line nuts and ceased pistons. HELP.

[Mark Maras]

Has the Z been sitting for a while? I'd start by pulling the caliper with the stuck piston and refresh (new o-ring) it first. Chances are the other caliper needs it too. Any possibility the calipers are on the wrong sides? The bleeder screws should be up not down.

[moozieman]

2 minutes ago, Mark Maras said:

Has the Z been sitting for a while? I'd start by pulling the caliper with the stuck piston and refresh (new o-ring) it first. Chances are the other caliper needs it too. Any possibility the calipers are on the wrong sides? The bleeder screws should be up not down.

Yes, it has been sitting. I can confirm that the calipers are on the correct side. One of the two front calipers work. And it's hard to work on because I can't get it taken off the brake line. The bolt is stuck and stripped.

Edited September 10, 2019 by moozieman

[siteunseen]

All mine are rounded off on my '77.  I use these for the flare nuts...

[moozieman]

Just now, siteunseen said:

All mine are rounded off on my '77.  I use these for the flare nuts...

I tried those. Maybe ill let it soak in some wd40 or sumn first

 

[Mike]

Not sure if they are rusted/seized or not.  So, you'll have to determine if that's the problem first.  After you get them pumped out, replace with Speed Bleeders.  But, don't install these until you are sure the lines are clear and the calipers aren't shot.  See the following post:

 

[Zed Head]

File the flats on the nuts down smooth and parallel,  Get some vise-grips like site showed or even bigger, with jaws that are in good shape.  Clamp the vise-grips down very tightly on the -nut, it's half=destroyed anyway.  Heat the area around the nut with a torch or a heat gun.  Put some force on the vise-grips and it should break loose with a sound like it broke.  If the vise-grips start to slip at all take them off and refile the nut flats and reset the vise-grips.  Take 20 minutes to setup and 20 seconds to actually break it free.

If you're not getting anything at the MC bleeder then you also have a problem with the seals in it.  Reman quality can be pretty poor, take it off and swap it for a new reman.  Probably has a lifetime warranty.

"The bleeding nut on the MC for the rears didn't release anything."

[Mark Maras]

 I've had better luck using good (not HF) channel lock pliers than vise grips to grip stubborn bolts, nuts, and studs.

[Patcon]

These

or these, might help

If the system is old then all four wheels really need to be disassembled, cleaned and inspected. If there is any rust or pitting in them, they can be difficult to rebuild. If they clean up you can just replace seals and reassemble. This applies to the master too.

[Patcon]

Also were you using flare nut wrenches to start with?

If not, you will fail 90% of the time. Brake flare nuts are soft. So they are easily destroyed or damaged

[moozieman]

4 hours ago, Patcon said:

Also were you using flare nut wrenches to start with?

If not, you will fail 90% of the time. Brake flare nuts are soft. So they are easily destroyed or damaged

wasnt using those, just a standard wrench

[Patcon]

21 hours ago, moozieman said:

wasnt using those, just a standard wrench

Standard wrenches really aren't up to the job. Even flare nut wrenches won't do it sometimes.