Phil,
The brake master cylinder pushrod is not the barrier to the fluid in the
master cylinder. The barrier to the fluid is a piston inside the master
cylinder, along with some rubber seals around the piston to stop fluid
going around the piston. The push rod rests against the end of the piston
usually in an indent in the end of the piston, supposedly in the dry. When
the brake pedal pushes the pushrod, the pushrod pushes the piston which
forces brake fluid along the brake line. While the pushrod passes through a
rubber boot at the very outside of the master cylinder, that's looked on as
a dirt barrier, not a fluid barrier.
This means that you should be able to remove the pushrod without impacting
the fluid situation at all. That's in theory, because I don't know your
set-up exactly. If you have to remove the master cylinder from the car to
gain access to the pushrod, then you would have to drain fluid because you
would be detaching the brake lines.
Daryl
----------
> From: Philip Hubbard <phubbard@carroll.com>
> To: mgs@autox.team.net
> Cc: spridgets@autox.team.net
> Subject: More Brakes - Blue Sticky Substance?
> Date: Sunday, July 12, 1998 7:55 AM
>
> Fellow listers,
>
> I've been blessed with some good advice on the list lately concerning my
> brakes. Acting on some of that advice, I decided to check the easiest
> thing first - are my brake pads getting free movement in the caliper
> assembly so that they can retract.
>
> After pulling out the pads on the driver's side I found a blue sticky
> substance spread thinly and evenly over the entire back of both pads. A
> tiny amount also had gotten on the lip of one of the pistons. What the
> heck is this stuff and should it be there? I didn't put the pads in -
the
> shop who rebuilt my calipers did that for me. In my lack of experience
I'd
> say that the stuff looks like that gasket maker stuff. I can't believe
> that such a sticky substance should be near my calipers.
>
> Also, I have no anti-squeal shims as part of my assembly. I think the
pads
> I bought were supposed to have some built in anti-squeal. Unfortunately
I
> threw away the box already. In any case, I haven't detected a squeal
yet. :)
>
> Lastly for now. To check the master cylinder push rod to ensure that
> pressure can be relieved when I release the brake pedal and therefore not
> cause my brakes to bind, I assume I have to drain the brake fluid out
> completely first. Not good enough to just suck it out of the reservoir -
> this would leave too much fluid in the area of the push rod, no?
>
> Thanks a million for all the help. I've stopped for the moment until I
> understand the mystery of the blue sticky substance.
>
> Philip
> Burgundy 1974 Midget
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