I decided to rebuild my brake servo after at least 20 years since the last
rebuild
kit. I have used silicone brake fluid for many years so didn't expect to
find any
rust or corrosion. When I got it opened up the insides were still like new
with
no pitting or scarring. The rubber seals were another story. The rubber
seals
were the consistency of uncooked bread dough. They just fell apart in my
hands.
After seeing this I decided to kit my front calipers since they had never
been done since new. I was expecting the seals to be shot but they were in
very good shape,
not deformed at all. The pistons had a few rough spots so I replaced them
with a
new set of stainless steel pistons from Rick at S.S.
I installed the booster and the calipers back on the car and tried to
bleed the
brakes. I would get good pedal but then the brake would slowly go to the
floor.
This made me think the fluid might be blowing by the seal in the master
cylinder so
I pulled it off to take a look.I was amazed. The seal had turned to a
substance
that looked more like black toothpaste. Some of it was like tar sticking to
the inside
wall of the master cylinder.
I guess my next step is to pull off the rear drums and change the seals in
the rear
cylinders. I'll let you guys know what I find.
Sorry to make a brake job so long winded but I wanted to warn those of you
that may have switched to silicone many years ago and have been happy with it
like I
have been. You might want to take a look at those inner seals. I had always
heard
silicone was inert and wouldn't react with anything. Does anyone know the
life
span of these seals with silicone?
John Mears
Modesto, Ca
B9471072
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