Our mechanic is getting frustrated - = more so because I'm always asking questions trying to understand the = systems, etc.  So I'm turning to the list to get some additional = information hopefully.

About five years ago we started having = problems with our 1990 Westy going through front brake pads like = crazy.  They were glazing and cracking for no apparent reason = according to our former mechanic.  Since that time we've moved and = our new mechanic found one of the caliper cylinders was scored causing = the pads on that side to drag.  He also informed me the rotors = didn't have sufficient material to be turned and that they would have = to be replaced in the near future.  I decided rather than try to = repair the damaged caliper that we would replace it and while we were = at it replace the driver side too.  Our mechanic proceeded to = replace both calipers, rotors and pads.  This was about 16 months = and 14000 miles ago.

About two weeks ago my wife, daughter = and I embarked on a 1500 mile driving/camping vacation.  Two days = into the trip the wear indicator on our brakes began to squeal.  I = figured since we were doing mostly highway driving that we could make = it back home before we had to have it looked at.  The only real = problem turned out to be driving into a quiet campground late at night = and hearing that squealing every time we tapped on the brakes.  = Well, we made it home and I brought it to our mechanic and asked him to = pull the wheels and inspect the brakes because they were = squealing.  His comment was, "Did ya drive on any dusty = roads?  It's probably just dust in the brakes cause those pads = should last 40,000 miles."  Later that afternoon I got a = call.  My mechanic told me that the passenger side caliper was not = releasing properly and he didn't know why.  He's now searching for = the reason.

I would like to get some feedback from = the resident experts on the list.  Can you provide me with a list = of probable causes for this problem?  I'll start off the = discussion with a guess of my own.  Something is keeping the brake = fluid from flowing back towards the master cylinder therefore keeping = pressure on the caliper and not allowing the pads to "bounce = back" from the rotor.  I suspect the problem is in the = proportioning valve assuming that the lines for the front brakes = diverge at this point.  Of course it could be a small blockage in = the brake line to the passenger side which allows the high pressure = past but moves into a blocking position when the relatively low = pressure return flow starts.  I just don't know.

I'm prepared to replace the master = cylinder, brake lines, proportioning valve, metering valve and pressure = switch if necessary.  I would also appreciate your feedback on = this.

Thanks in advance,

Tom Moritz