I've got a '76 MGB that's exhibiting a problem with brakes and was
hoping that some kind people out there might be able to steer me
in the right direction for troubleshooting and/or repairing this
problem.
The problem:
The brake system seems to lose pressure when the engine
is idling slowly. The pedal goes farther to the floor
than when the engine is revving higher. Sometimes it
feels like there's almost no brakes at all - the car
is difficult as hell to stop.
This is particularly noticable when I come off of the
highway, put the clutch in letting the engine go to a
low idle while approaching the stop sign at the end of
the off ramp. My son actually went through a light
because he couldn't get the car to stop quick enough.
You can actually feel the pedal drop toward the floor
if your foot's on it.
Downshifting into a lower gear and letting the engine
rev higher keeps the brake pressure up.
What I've done:
I've bled the brake system with no effect whatsoever.
Talked to a couple of people. One suggested that it
might be the servo unit. He said only a mechanic would
be able to tell if it's really working (ok, how?). And
apparently new servo units are not available - the
current one must be rebuilt.
I've looked at the little check valve on the intake
manifold that connects to the servo unit. It seems to
let air pass in one direction, not in the other (as I
might guess). The line going to the servo seems intact
(i.e. no obvious slits, holes and not plugged up).
So, I want to know:
Am I following the right trail by looking at the servo?
Or is the master cylinder really to blame? OR....?
Any tips on what to look for (at)?
Thanks bunches.
mcleod
--
Rick McLeod mcleod@sgi.com
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Hardware Developer
Technical Program Manager "He's no fun.
Silicon Graphics He fell right over."
Mountain View, Ca. - Firesign Theatre
(415) 390-3137
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