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The front right rotor on my 94 6MT LT1 has been a constant bother as long as I've had it. Original at time of purchase seemed to be warped. Replaced all with drilled/slotted and new pads. Not long after, front right seemed to be warped again. Had turned, then months later, turned again. Then all hubs and front calipers and hoses replaced. Still symptoms of a warped rotor. Last week, installed two new front rotors of the same type to start fresh. Immediately hearing a rhythmic rubbing sound from the front right as I'm driving that stops when I apply the brakes. Jacked it up, and the pad seems to contact the rotor for about 3 inches of the rotor area every turn. Took it all apart, put it back together, problem persists.
What do I do now? I don't understand why this rotor seems to be unstraight from the factory. At this point, all parts between the suspension and the wheel are new within the last 6 months.
Does the car have any accident history? Is it possible the spindle is bent? I would remove the rotor and check the spindle's relationship to the caliper. At this point the rotor not being straight is a symptom of a larger issue.
If you have J55 13" rotors are directional, internal fins are curved. Improperly torqued lug nuts most common cause of brake pulsation. You will need dial indicator to check rotor and hub runout. The lug nuts should be snug against rotor to check run out .005 or less. If excessive mark high spot remove rotor. Check inner rotor and hub surfaces for corrosion or build up clean as necessary. Check hub run out less than .005 mark high spot. If both are ok install rotor on hub with high spots as close to 180* apart as possible and recheck rotor run out. Is run out acceptable?
What about examining the caliper itself? Are both pistons pulling back fully?
I agree, and it's worth remembering these calipers aren't fixed, they've got some side to side movement in them.
What about the tires? How old are they and have they been replaced during this time? One could be out of balance causing similar issues.
The other thing to consider is if you've been causing pad build up. If you have a hard stop and then sit with the brakes on, you're gonna leave a deposit on the rotor that's gonna almost never come off and will vibrate. If the issue was going away after your fixes, it's possible you're just causing the issue over and over again.
Possibly that one wheel has warpage where it mates with the rotor. You could swap it with the left one to see if the problem appears on the other side.
Make sure you torque to factory specs, (I believe 100 lb. ft.) and do it in a star pattern. Start at 40 lbs. and work around the wheel in 20 lb. increments until full torque is reached.
Possibly that one wheel has warpage where it mates with the rotor. You could swap it with the left one to see if the problem appears on the other side.
This is what I was thinking when I read the OP.
Yet, he must also check to see if he has directional tires to see if he can swap sides, no?
I guess it wouldn't hurt the tires to do this for a minimal amount of time for testing, though.
Another thought is to move the rotor from one side to the other to ensure the 3" scrape goes along with it.
Does the car have any accident history? Is it possible the spindle is bent? I would remove the rotor and check the spindle's relationship to the caliper. At this point the rotor not being straight is a symptom of a larger issue.
No accidents, but I suppose a large pothole could have bent something before I bought it. I'll look into checking the spindle, do you have any tips for doing that?
Originally Posted by FAUEE
I agree, and it's worth remembering these calipers aren't fixed, they've got some side to side movement in them.
What about the tires? How old are they and have they been replaced during this time? One could be out of balance causing similar issues.
The other thing to consider is if you've been causing pad build up. If you have a hard stop and then sit with the brakes on, you're gonna leave a deposit on the rotor that's gonna almost never come off and will vibrate. If the issue was going away after your fixes, it's possible you're just causing the issue over and over again.
Tires, wheels, and the initial set of rotors/pads were bought and installed in May '18 just after I bought the car. Tires and wheels have remained the same, front rotors, pads, calipers and hoses are all new within the past few months.
I did a proper break in procedure as described by the manufacturer for these new rotors, as I thought I may have screwed up the old ones. So I would say these new rotors have no uneven buildup, and only have maybe 50 miles on them anyways.
Originally Posted by johnnymo63
Possibly that one wheel has warpage where it mates with the rotor. You could swap it with the left one to see if the problem appears on the other side.
Make sure you torque to factory specs, (I believe 100 lb. ft.) and do it in a star pattern. Start at 40 lbs. and work around the wheel in 20 lb. increments until full torque is reached.
This is something I considered, and tested by removing the wheel and reinstalling the lug nuts directly to the rotor. Then I could turn it by hand and see exactly where it was contacting. So I think the rotor contacting without the wheel proves its not the wheel, but maybe the spindle/hub, as @Hardway said.
Took everything back apart on both sides today and guess what- the driver side has a new hub and the passenger (problem) side does not, when it should. So everybody double check your shops work when they say they replace stuff, cause I was floored. Got a new one, installed it, everything working great now.
Now trying to find my receipt so I can dispute some charges with my shop!
Never Ending Rotor Issues!
