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Dragging brakes


I just saw you post about the brakes sticking. I had the same thing happen
to my '84 5000S about 3 years ago (it is annoying as hell, isn't it???)

I would bet the farm on the master cylinder. After much head scratching
and trying things I unbolted my master cylinder from the hydro booster
to try to isolate the problem to either the booster system or the brake
system itself. The idea was to separate the two systems. Anyway, while
I was fiddling around with the master cylinder I heard a slight snapping
sound followed by the releasing of the brakes.

Further head scratching and testing revealed that when the brakes locked
I could free them by pouring cool water on the master cylinder or sometimes
by tapping the master cylinder with a hammer.

I ordered a new master cylinder from IPC and when it arrived I noticed
that the plunger would move smoothly when pushed. After swapping the master
cylinder I noticed the old plunger was very rough and had a slight detent
about 5 mm from the return position. I can only imagine what the thing
was doing at temperature... I have not had any problems since.

Try IPC and get a price on the master cylinder. Mine was obscnely cheap
($35-$40, as I recall) but yours may be more. It is not hard to replace
but I would also replace the reservoir as it may have dirt or some other
unsavory substance in it and they are impossible to clean (trust me - I
tried.) Mine had a lot of black goo in it which I suspected as being
a contributing factor in the cylinder's failure. It goes without saying
that you will want to bleed the brakes GOOD after changing
the master cylinder, so have plenty of fresh fluid on hand.

Hope this helps.