The Silicon fluid will have a lot to do with it. Before putting in the
silicon fluid, your brake system may not have been completely flushed and
cleaned. If there was some of the standard fluid still trapped in the
line and silicon added to the system, the DOT 3 fluid will decompose the
silicon. It happened to me on my master cyclinder. A very reputable
servise center bleed my brakes that had silicon fluid in the system and
topped it off with DOT 3 fluid. Even though the repair ticket warned
them that there was silicon in there. They assured me that they had called
an oil company to find out the results and said it would not harm the
system, WRONG! It took a little over a year for it to happer, but it ate
the seals and left a sludge of black grease mixed with sand.. Also dest-
royed the paint job on the firewall shelf where the fluid had leaked.
Silicon fluid is great, but be very careful to flush your system completely.
----------------------------Original message----------------------------
MG4EVR@aol.com wrote: "I just put a new master cylinder in my 73 midget, and
am not getting any
fluid to the rear brakes. I bled them for an hour and still can't get any
fluid to the rears. The fronts beld out perfectly, any helpful hints out
there?"
Ya know, the same thing happened to me. I had a new master cylinder put on
my 1977 Midget a few months ago. I always felt that there was still air in
the line because the pedal felt a little low and sometimes mushy. Then
suddenly a couple of weeks ago my brake pedal got really hard to press and
started working up higher than it had been before. I went to a friend's
house and we proceeded to bleed the brakes. Fronts responded normally. When
we got to the rears, nothing would come out. When the bleed nipple was
opened all the way the pedal would not go to the floor.
I took my Midget to the local British repair shop for diagnosis. The
repairman found that the rear brake lines were completely plugged with some
sort of black tar-like substance. I ended up replacing the flexible portion
of the line and the rear wheel cylinders as a safety precaution. The shoes
were also shot and they were replaced too. The repairman couldn't offer any
explanation of the blockage.
Now the brakes work fine. I'd like to know what caused this blockage so I
can't try to avoid it in the future. By the way, I'm using silicon brake
fluid. Does anyone think that that could have played a part in this
situation?
Perplexed as usual,
Gary Watson
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