If they dragged and ate a rotor, I'll bet it was the outside pad that was
wasted and not the
inner pad, and that is an indicator the slides froze and wouldn't let the
caliper move when the service brakes were released. Its one of the
reasons I don't like rear disk brakes, Everything is exposed and for some
reason the rear calipers get nailed with all the garbage off the road. But
still the biggest issue with the design on your Lumina, and all GM rear disk
of that era except the Corvette, was out of adjustment condition resulting
in the two piece caliper being pulled apart by hydraulic pressure and then
leaking, resulting in a parking brake that didn't hold, and a low spongy
brake pedal. It was a great design in theroy, and if people really saw what
the park mechansim in a automatic tranny was they would never not use the
parking brake, and the out of adjustment aspect would never have come into
Most people dont even realize that the original automatic trannies didnt
have park, just reverse, neutral, low and drive. Park was added because
people would shut it off in drive, then start it and hit what ever was in
front of them so park was added, and then sometime after that the nuetral
safety switch was added as well. when park was added, parking brake useage
took a nose dive. We be a lazy animal.
It shouild be noted that the Ford design of the same error was a resound
flop as well with its own issues.
Fixed mount calipers require a seprate parking brake mechanism, and because
they are fixed mount, dont have slides to fail or freeze. But then again
Mercedes and Volvo loved fixed calipers back then and you could hear them 5
miles away when they hit the brakes. Fixed mount calipers have major issues
with harmonics, which is why Mercedes gives a discard thickness, and
recommends rotor replacement rather than machining.
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