Brake servo reply (BTDT)

[Sdbigelow@aol.com]

Earlier today, Dan Dan the Battery Man sez:

/I have been having some brake problems on my 5ktq and it may have been
/initially misdiagnosed as a master cylinder, but talking to the local
/expert, he is thinking it may be the brake servo (also called the
/booster??) just behind the brake MC.  But, I have never heard of anyone
/replacing one and no one has ever thought it was that before.  The
/problem seems to be inconsistent pedal and brake pressure (NO, it's not
/the brake accumulator!).  Does this sound like it could be the
/problem...bad brake servo?  How much are they?  And, do you have to get
/a new MC when you replace this?  Any ideas?

Dan, I've just been through this, with the added complication of a defective
four month old bomb. I'll assume you've done the bomb test, and passed. In my
case, even a new bomb wouldn't hold pressure because it was leaking through
the servo. When I pulled the return hose @ the reservoir and started the
engine, fluid came out in great gushes. Of course, without touching the brake
pedal, it shouldn't. Also easily mis-diagnosed as a bad pump, because
pressure _is_ low. However, it's caused by the servo leaking faster than the
pump can deliver.

"Now, well, that's all very well and good Steve," you say, "But what"s up
with my rig"?

Bad news: I don't know. 

I can tell you to make sure your expert is just that, and good with a
pressure gauge. My used servo was $100 (new one's a freaking fortune), an
hour's labour, and a bucket of Pentosin. You don't have to replace the M/C to
change it, or even remove the M/C for that matter. Just be careful when
bending it and the lines out of the way. 
Rebuilt M/C is about $70 locally, but of course will require a full bleed. We
all know what will happen to that last bleed nipple...:(

HTH, shoot back if you have any more ???

Steve Bigelow
Ottawa Ontario
Masonry Restoration Engineer
84 5ks freshly washed for the rocket ride to Montreal tomorrow
GO JACQUES!