rear backing plates for 71z brakes and silicone fluid

[EverRude]

Replacing my entire brake system. Notice some PO bent up the rear backing plates and presume using them to pry off stuck drums. Hopefully I can straighten them. What is a good sourse for replacements if not?

Also since I am replacing my entire brake system and considering using silicone fluid. The inability to absorb water should make replacing metal parts less necessary in the future since they should not corrode as much. Am I wrong?

[Carl Beck]

You are correct. Silicone fluid also protects the rubber parts in your brake and clutch systems. It will not peel your paint if you spill a little either.

The downside is that it can be harder to bleed and should not be used for competition. I've ran it all my Z's since 1975. It greatly extends the life of brake and clutch components.

FWIW,

Carl B.

[EverRude]

Thanks Carl. Yeah doing clutch master and slave as well. Need to add a line to that and swap it for silicone. Hadn't thought of it. I even heard the sound of rust crunching inside the apparently new slave while bleeding.

One other question. Is there any benefit or detriment to a 280z or early 280zx (verticle mount) on a 240z with stock brakes. I know the zx has. 15/16 bore so it moves more fluid. Will that make pedal throw uncomfortably short? And the 280z lists as not compatible with 240z, why? Looks sam except reservoirs. This where they swapped position of which reservoir served which end of car.?

Edited March 17, 2011 by EverRude

[EverRude]

Finally figured out for myself that the backing plates are part of strut tube. No choice but to try and fix then as best I can when I install brakes.

[LeonV]

Finally figured out for myself that the backing plates are part of strut tube. No choice but to try and fix then as best I can when I install brakes.

Incorrect, the plates bolt to the strut.

[Arne]

...the plates bolt to the strut.

True. But you have to split the flanges and replace the rear wheel bearings to replace them.

If you do decide to replace the backing plates, I'd consider using the plates from a later S30, as rear wheel cylinders for the later cars ('72-78) are more affordable, and easier to come by.

[EverRude]

Gah wish I had asked this before. Just bought a set of those incredibly expensive series 1 wheel cylinders. At this point it seems I am committed to this. Repair should be doable though it may require some heat. Bending tin is what I am best at so I'll go with it.

I was confused because I read several rear disk conversion threads that stated to cut the backing plate off. Noone seemed to mention the ability to remove it. Guess they need part of it in place as a spacer and or saving themselves the headache of removal and reassembly?

Thanks for correcting me and the advice guys :-)

Edited March 17, 2011 by EverRude

[Zed Head]

I almost posted similar information but wasn't sure the 280Z plates would work on a 240.

I put 1978 strut assemblies on my 1976 car and found that 1978 cylinders are in the $20 range, while 1976 cylinders are in the $60 range. The 78s are dual piston while the 76s are single piston with a sliding cylinder for adjustment. Less machining cost on the on the dual piston I assume.

Those prices are Oreilly Auto. MSA is even higher. Looks like the 240 cylinders are up in the 80s at MSA.

[EverRude]

Yep. 240 are crazy expensive. Rotors were higher priced too. Double the price of 280 atleast what I was looking at.

Noone have info about the differences in masters? Would the zx master be too much for a stock setup?

Edited March 17, 2011 by EverRude

[Arne]

I was confused because I read several rear disk conversion threads that stated to cut the backing plate off. No one seemed to mention the ability to remove it.

They cut them off because they don't want to mess with the wheel bearings. If you are doing wheel bearings at the same time, they are an easy bolt-on part.

[LeonV]

True. But you have to split the flanges and replace the rear wheel bearings to replace them.

If you do decide to replace the backing plates, I'd consider using the plates from a later S30, as rear wheel cylinders for the later cars ('72-78) are more affordable, and easier to come by.

I guess I'm just used to going all out! When I do something like brakes it usually ends up being a much bigger job... "say those bearings are pretty old", "should probably replace these nasty bushings too", "might as well paint the suspension while it's apart"...

[EverRude]

Yeah I have a problem with while-i'm-at-it-itis... Specifically forcing myself not to do it this time. I have a 70 Mustang that is still in pieces waiting for body work and paint that started out as a suspension upgrade 3 years ago.