I need a sanity check.

So in the course of my race car rebuilding (see https://honda-tech.com/zeropost...53944), I now have mushy brakes. The new car as purchased had mushy brakes, but my old race car did not. So we swapped over all four corners of the brake system including the SS lines from the old car to the new. And we bled them really well (ran a quart of fluid through it with a power bleeder). So the only remaining items are the master and the booster.

Additional symptom: With the car off, I initially get a hard pedal, but pushing it harder it very slowly goes down to the floor. Sounds like the master is slowly bypassing?

I've had masters go bad before but they would bypass more suddenly as you pushed harder (car off).

What is the collective expert wisdom here? Master?

What's the symptom as a booster wears or goes bad?

I suppose I could just swap them both but its more work...

--Andy

 

A slow drop to the floor sounds like master cylinder, as does the mushy pedal. A bad booster should give no, or little, boost and cause a very hard pedal, but not a dropping one.

Did you find what was causing the camber issue on the driver's side?

 

Yup, it's the MC. Also check for any leakage on the rear wheel-cylinders, another possible culprit for crappy pedal feel.

 

And the master will also generally show its leaking if the bottom area of the booster has all the paint peeled off of it.
Brake fluid + Paint = Rust.

If you put a new MC in it make sure you bench bleed the crap out of it first.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mohudsolo &raquo;</TD></TR><TR><TD CLASS="quote">
Did you find what was causing the camber issue on the driver's side?
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I believe so. So the other thread. Looks like the new car also had a tweaked upright (not as bad as the bent car, though). I'll have another part either today or tomorrow to go on there.

--Andy

 

Twas the master cylinder. All better now. Thx. --Andy

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Andy Hollis &raquo;</TD></TR><TR><TD CLASS="quote">Twas the master cylinder. All better now. Thx. --Andy</TD></TR></TABLE>

Well what also happens is the brake fluid, from the leaking MC, gets into the brake booster and starts to eat up the diaphram, then you get a vaccum leak and poor brakes.

BTW, this usually happens at the worst time.

 

Twas the master cylinder. All better now. Thx. --Andy