Samuel---Parts of your inquiry, like a sudden drop in brake pedal, sound
familiar. Also the seizing of the front brakes after new master
cylinders and/or changing over to the silicon brake fluid. Never
experiencing the seizing phenomenon in any of my cars, I can't give my
own example of a fix. But I can tell about my having the same "tipping
valve" in the original master cylinder for 27 years. It obviously has
not caused a problem, or it would've been out of there. These tippers
still come with brake MC rebuild kits from TRF. I don't think Moss
includes them in their base kit anymore, and their price reflects this.
I can't see what would ever wear out here, still it's been written that
a faulty one won't allow the brake fluid to return to the MC after
applying the brakes. Tim H. is a believer in this, and I have no reason
to doubt him.
The silicon fluid, or the method of changing over to it, continues to
cause concern to many. It's written that system cleaners such as mineral
spirits and alcohol shouldn't be used, as it can "cause problems." Well
if you can't use these, and glycol and silicon won't mix, what's an
enthusiast to do?? Use air pressure to force out the old fluid?
Completely disassemble the system and clean with what,... water? Then
blow dry?
It kind of figures that the brakes would release after being allowed to
cool off. Especially if the heated fluid in the line expanded thru
trapped air bubbles, and couldn't return to the MC for any reason.
Finally, since it's noticed that brake pedals "fall" after turning sharp
corners, going forward OR backwards, maybe this action can push the
pistons back into the calipers, thus releasing the hold the pads have on
the discs. I wouldn't want to rely on this method for long, but perhaps
it would get a guy or gal home.
Dick T.
'73
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