last weekend while on the way to work on my regal, i kept hearing a harsh noise coming from the left front wheel of my mother's 92 roadmaster. monday i pulled the wheel, and saw THIS :shock: :shock: :eek2: :eek2: this is what it looked like when i took it off :shock: :eek2: i looked at the right front rotor, it was in excellent shape.i inspected the caliper closely, the piston went back in the bore when pushed in. i did notice the wheel bearing was a bit loose. what happened here?? it was in for a 21 point inspection 4 months ago, but the "tech" told me all was ok. i can't imagine how he could have missed the metal filings caked on the inside of the wheel ou: so,after she got what parts it needed, i got it fixed good as new :TU:
Wow, that is bizzarre. Never thought it could happen, so sorry - I don't have a clue as to why that failure might have come about.
Jeff, I have worked on the machines that machined that rotor casting and pressed in the studs and bearings. Most likely, that failure is due to a casting defect from the foundry such as porosity or a hairline crack in the area where it broke. We refer to the part with the studs as the "hat" of the rotor and the flats as the "plates". I'm going to print that out and take it around. I'll let you know if I scare up any other info.
thanks Annie!!the hat was the only thing turning when i removed it, destroyed the outer plate,and outer pad. should i keep a close eye on the right side? it was in very good shape at the time i replaced the left side. i would have replaced it sooner, but i had no idea it was like this
Jeff, I went to the Metallurgical Lab and some of engineering. Haven't found anyone yet who's ever seen a failure quite like this. All are suspecting a crack, which worked it's way around the hat. Where the hat and the plates come together, there is a machined relief groove which is there partly to relieve any stress in that area. A crack could have been there since the rotor was casted or could have been introduced later. Was the car ever involved in an accident, or even hit a curb pretty good on that side? That could have caused an initial crack. Since I am finding that this is very unusual, it probably will not be a problem on the other side. BUT, if for piece of mind you wanted to pull everything and inspect the area for any cracks, that's about all you could do. I'll keep asking around. I haven't run across the older Process and Product engineers yet. Were these the original rotors on the car (if you know)? Have they ever been turned? About how many miles on them?
as far as i know, they are original. car has 261k miles was never in an accident, or hit curb hard on that side. right one was very good, with little wear
so i guess welding back together while it was still on the car was out of the question?? :shock: about 15 years ago or so my cousin tony had that happen on hos 76 monza. my brother told him it just made it easier to change/grease the wheel bearings. :laugh: glad you got it all fixed before anyone suffered injuries. i bet that would make for some fun braking in the rain.
I've had that happen to me twice before. Once was on a 84 Cavalier, and once on my 84 RWD Cutlass (although.. having to stop the new 455 might have contributed to it's strain though :Brow: ) Sure is a he!! of a thing to listen to as you're driving though :shock: I thought a wheel came off. Speaking of sounds... ON that same Cavailer, I went way too long between pad changes and wore completley through the outside surface of the rotor... It started using the vents for braking surface :error: That sure was a distinctive sound ou:
After looking at your pic, that's exactly what my worn rotor on the cavalier looked like (yours has some life left though if it hadn't cracked..lol). Did you check to make sure the caliper was sliding freely on the bushings (and regrease them)??? My caliper bound up on the bushings and that's what caused the lopsided wear. I cleaned up the bushings real nice and regreased them... didn't have a problem with it after that.
WOW!! I wish you'd shown that view before! Do you see how one plate is nearly gone, very thin? Both should be the same thickness (or reasonably close). I'm guessing the thin plate was the outboard side (the side towards the tire)? What it looks like is that only one side/pad of the caliper was engaging - or with much more force than the other and it has wore one plate and not the other. If the thin plate is the outboard plate, you can see how it has gotten so thin that it could has caused an integrity problem at the plate/hat interface, either inducing a crack at a weak spot or revealing a pre-existing one. There was obviously a long time problem with this brake corner - a frozen caliper, bad slides, a bad piston, etc. Take a look at the rotor one the other side and see if the plates are of similar thickness or if they are worn unevenly.
i did, they were the same thickness. the thin side was the outer. the caliper slides/bushings had normal road dust, seemed to move freely.piston had some surface rust,polised it off, moved freely. i did have the car at our local dealer$hip, had a 21 point inspection done approx 4000 miles ago. the tech did not alert me to this, had he done so, i could have caught it and fixed it sooner.from now on, i'll inspect them every 500 miles
