Brake Master Cylinder "Deflection" - Happen in our

Adam West · Post by **Adam West** » Sat Dec 15, 2007 5:31 pm

Interesting brace on sale on the GC boards. 1) will it work with our cars? 2) do we even need it?

Half way down the thread is a diagram that shows why the brake master cylinder might move due to firewall deflection under pressure.

What think?

http://www.rs25.com/forums/showthread.php?t=72152

Cheers,

AW

vrg3 · Post by **vrg3** » Sun Dec 16, 2007 9:13 pm

http://bbs.legacycentral.org/viewtopic.php?p=81970

The bracket they're talking about in that thread is meant for a GC.

jamal · Post by **jamal** » Sun Dec 16, 2007 11:03 pm

I think $65 makes that about the cheapest brace out there. I've been meaning to pick one up for awhile.

Adam West · Post by **Adam West** » Mon Dec 17, 2007 5:50 am

Yes, for a GC...correct. Would have to be retrofitted to work on our cars but do we even benefit from such a brace?

Yes, nice piece of work and very affordabe...

vrg3 · Post by **vrg3** » Mon Dec 17, 2007 6:32 am

Josh seemed to notice an improvement.

The GC chassis is almost the same as ours, so I would expect to see an improvement similar to what GC owners see.

Adam West · Post by **Adam West** » Mon Dec 17, 2007 6:59 am

i.e. very small improvement only if noticing mushy pedal in the first place. Still, fun mod to do on a weekend. Will consider it.

Josh, much fabing work to get this to work?

vrg3 · Post by **vrg3** » Mon Dec 17, 2007 7:12 am

I wouldn't bother with it unless you've already switched to stainless steel braided brake hoses and a single-stage brake booster.

Adam West · Post by **Adam West** » Mon Dec 17, 2007 7:19 am

Already switched to stainless steel braided lines blue fluid but not the single stage brake booster. I read about single stage vs. two stage and feedback on both a long time ago. Remind me again? I think a change to single stage is a real piece of work...

vrg3 · Post by **vrg3** » Mon Dec 17, 2007 7:24 am

You should be able to find old posts by me comparing the single and tandem stage boosters, and explaining the swap process (which actually isn't so bad).

Post by **Legacy777** » Mon Dec 17, 2007 7:55 pm

I don't know if the issues I had were due to MRT's poor QC or differences between the GC chassis.

The brace isn't a bad mod, and the one in the link above looks like it's a little better design....may be harder to install though. But I don't think this would be my first brake mod. I posted deflection #'s on nasioc I believe. I don't recall if I posted them here or not.

Also....I just need to point out that the brake boosters are NOT staged, they are simply tandem or single diaphragm boosters. The tandem booster moves as one unit.

I posted on nasioc with pictures of a disassembled tandem booster and some tech info.

Here's the pics
http://www.main.experiencetherave.com:8 ... kebooster/
http://www.main.experiencetherave.com:8 ... ebooster2/

vrg3 · Post by **vrg3** » Mon Dec 17, 2007 8:52 pm

To clarify -- There are two stages of boost, but they don't work in the sequential way that most people seem to think. Tandem-stage boosters have two diaphragms that act together to make it easier to press the pedal initially and then that act against each other to make it easier to hold the pedal.

That is, if I understand the factory service manuals correctly.

Post by **Legacy777** » Mon Dec 17, 2007 8:58 pm

I don't know if I'd use the word act against each other. I think I know what you're getting at, but it's been too long since I've looked at this stuff to remember exactly how the wording was put forth in the FSM.

vrg3 · Post by **vrg3** » Mon Dec 17, 2007 9:14 pm

Well, let's take another look and decide.

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Brake Master Cylinder "Deflection" - Happen in our

Brake Master Cylinder "Deflection" - Happen in our