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