Re: Rotors, Hubs, brake vibration

["Tom Harais" <tjhemh@domain.elided>]

John:

> This is a common problem on Scouts.  My Traveler does it, John
Hofstetter's
> does it and many more obviously do too.  Now what causes it?  I'm not
> entirely sure, but I do know this... I did a complete brake job on my
> Traveler a few months after I purchased it and I'd say within 6 months is
> was doing the "grabbing" or "pulsed stropping" thing you described.  It
has
> progressively gotten worse to the point where I started looking for the
> cause in the last six months.

Along this line may I remind all that I once paid a shop (I was on an
out-of-state elk hunting trip and had no choice but to get it repaired and
move on) $115 for a new, driver's side rotor on my Scout. The old one had
been groved badly and worn unevenly, by the non-existent brake pads. 

I drove it 600 miles home from Yakima, WA to Antioch, CA only to notice
that the brakes "pulsed" some as I applied them lightly. To make matters
worse, there is a loud, noticeble "whoosh, whoosh" sound coming from that
wheel as I drive down the street. That sound, is the sound of an
out-of-round brake rotor moving the caliper back and forth across it's
mounts. This, from a brand new rotor.

Hofstetter is the one that told me this was a fairly common occurance
amongst new rotors. There were built up stresses in the metal which
"relieved" themselves by it's warping, after the rotor got nice and hot
during some stop I made. This is what cryogenic processing is supposed to
help prevent from happening in the first place.

Tom H.