A braking nightmare

[rocky raccoon]

Also posted in B'world since we have no chassis-specific forums.

Something else for you all to worry about and check.

While on a road trip to Vermont last week, driving my 1983 300CD, my right front brake suddenly made a horrible screeching noise and locked up on an interstate exit ramp. I pulled into a parking lot and removed the wheel. The inside of the aluminum wheel had a shiny circumferential streak but I could see no corresponding bright spots on the adjacent steering or suspension points. I reinstalled the wheel and test drove in the parking lot. The brakes locked up going forward but released when backing. After a few test runs in the parking lot, the left front tire suddenly lost air. I removed the wheel again and installed my spare. Same noise.

I then drove very carefully, not using brakes, to a nearby general auto repair shop. We put the car on a lift and examined the front components carefully. Nothing immediately appeared to be wrong but we kept looking and finally noticed that one of the caliper bolts was completely missing. Apparently the caliper misaligned when braking and scraped the inside of the wheel. The sudden loss of air was caused by the caliper wearing completely through the inside of the wheel.

Luckily, the shop had a caliper bolt which we installed, checked the rest of them and I completed the round trip from home to Vermont without further incident, about 1200 miles total. The calipers were changed by me in February of 2012, about 30500 miles ago. This was a freak and a good reason for using thread-locker on those bolts.