>> I was wondering if my TR250's brake booster is working like it should, the
>> usual failure mode (I assume) is the diaphragm cracking. So to test I should
If the diaphragm breaks, three things happen:
1. you now have manual disc brakes, which on a tr6 is NOT a pretty sight
2. the engine dies or idles poorly upon brake application (fix this
by putting a large bolt in the vacuum tube from the intake)
3. there is a hissing sound from under the dash near the brake
If this is not what's happening, then something else is wrong (I've repaired
5 of these now, including one 250)
>The way my booster told me that it was reaching the end of its life, was by
>ingesting large quntities of brake fluid. There were no visible
...
>of white smoke poured out of the exhausts. The cause was a split
>diaphragm, which allowed brake fluid to be sucked in by the engine.
There is no way to know at this point, but I put my money on the master
leaking first into the "primary" side of the booster and feeding the
engine fluid, followed rapidly by the disintegration of the diaphragm
due to the brake fluid.
After using the last "free" spare in the local stockpile (they seem to have
a 20 year life, so a junk spare is a short term solution) and being offered
one for $100.00 (bent unit from a wrecked car, condition unknown), or a NEW
unit for $295.00, my instincts told me "something is wrong here". I was
informed by the parts houses that the diaphram was NLA (I assume the NEW
units come with used diaphragms???). After ~40 phone calls I ended up with
a place in San Antonio which rebuilds boosters. Along the way was told that
a federal regulation prevented the sell of diaphragms to individuals?? In
any case, this place sand-blasted the unit, painted it, and replaced all
parts for $98.00 with my "jobber" discount (hey hey). A few details to
straighten out (black valve vs. white) and we'll be ready to list his
name. Another option is to open the unit and find out what part number
is on the NEW $5 diaphragm. Interested parties let me know, everyone needs a
spare booster.
rgb@hal.com
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