Question: metal on metal

[ocean]

i recently started hearing metal on metal sound from my left rear wheel on my 92 coupe with heavy duty brakes. i bought new pads, didn't help. metal sound is only at low speed with no brake being applied. shop manual says loose equipment probably the cause. i installed new brake rotor and still the metal on metal sound at low speed with no brake being applied. anyone else have this problem?

 

[John Robinson]

Check the emergency brake pads.

 

[LLC5]

When the noise is active, apply the parking brake and see if the noise goes away.

 

[boomdriver]

i recently started hearing metal on metal sound from my left rear wheel on my 92 coupe with heavy duty brakes. i bought new pads, didn't help. metal sound is only at low speed with no brake being applied. shop manual says loose equipment probably the cause. i installed new brake rotor and still the metal on metal sound at low speed with no brake being applied. anyone else have this problem?

Are you certain that you're not hearing a half-shaft joint on the way out? They can clang pretty good just before they fall out...

 

[ex-x-fire]

Those years don't have seperate pads/shoes for the parking brake. When you apply it, the cable pulls a lever that pushes the regular brake pad against the rotor.
I'd look for scrape makes on the old rotor, maybe the bearing is going bad.

 

[ocean]

metal on metal no more

thought i had a brake problem when a grinding metal sound started from lt. rear wheel. replace pads(they were still good but i did it anyway). no change. thank all who made suggestions but still had noise. not being the smartest card in the deck, i discovered after several inspections that the wheel nut retainer was loose. pulled the cotter pin and retainer and used 36mm socket and re-tourqued nut to 164 ft/lbs. the nut acually rotated almost 3/4 of a turn. the car has 144k. with the original wheel bearings. i didn't know that a pinned nut could cause the hub to become loose. suggest all c4 owners with high miles recheck hub nut and retainer periodically. everything is quiet again. mechanic could have changed wheel bearing hub and i would thanked him for a $500 bearing job that i don't need at this time

 

[boomdriver]

thought i had a brake problem when a grinding metal sound started from lt. rear wheel. replace pads(they were still good but i did it anyway). no change. thank all who made suggestions but still had noise. not being the smartest card in the deck, i discovered after several inspections that the wheel nut retainer was loose. pulled the cotter pin and retainer and used 36mm socket and re-tourqued nut to 164 ft/lbs. the nut acually rotated almost 3/4 of a turn. the car has 144k. with the original wheel bearings. i didn't know that a pinned nut could cause the hub to become loose. suggest all c4 owners with high miles recheck hub nut and retainer periodically. everything is quiet again. mechanic could have changed wheel bearing hub and i would thanked him for a $500 bearing job that i don't need at this time

THINK real HARD on what you said......

If the cotter pin was in place....that means the nut could not come loose....which means the bearing IS loose and getting ready to fall apart.

If it were me, I would immediately do 2 things.....There is'nt much holding these bearings in place...and the bearing holds the wheel. Easy to see what happens when a bearing separates while driving. :ugh


1. check the bearings by jacking the car up and grabbing the tire at 12;00 and 6;00 and trying to wiggle it in/out.
Rule of thumb.....if you can FEEL any movement the bearing assy is junk. IF you can SEE the movement, its dangerous and needs to be parked until it can be repaired with new parts.

2. Check the 3 HUB assy retaining/mounting bolts (torx) on the backside that can be seen by looking past the outside half-shaft U-joint toward the spindle. There are 3 45 torx bolts there. Those are what REALLY holds the hub on. That 36mm nut only holds the inner bearing race...thats why it appears to be worn out. That inner race had to gain some slack somehow...like the bearing wearing and allowing it to move or turn on the spindle. If you heard metal grinding...that was the race turning against the spindle...thats big trouble if it ground into it much. Fortunately spindles are easy to find used.

 

[ocean]

thanks for the heads up on why a bearing would become loose with the cotter pin still in place. i'll check torx bolts. down deep i knew the nut couldn't back off with the pin still in place but i guess i was looking for a quick fix. i drove 200 + miles today with no trouble but first thing monday morning i'll ck. torx bolts. thanks again.

 

[chevyaddict]

THINK real HARD on what you said......

If the cotter pin was in place....that means the nut could not come loose....which means the bearing IS loose and getting ready to fall apart.

If it were me, I would immediately do 2 things.....There is'nt much holding these bearings in place...and the bearing holds the wheel. Easy to see what happens when a bearing separates while driving. :ugh


1. check the bearings by jacking the car up and grabbing the tire at 12;00 and 6;00 and trying to wiggle it in/out.
Rule of thumb.....if you can FEEL any movement the bearing assy is junk. IF you can SEE the movement, its dangerous and needs to be parked until it can be repaired with new parts.

2. Check the 3 HUB assy retaining/mounting bolts (torx) on the backside that can be seen by looking past the outside half-shaft U-joint toward the spindle. There are 3 45 torx bolts there. Those are what REALLY holds the hub on. That 36mm nut only holds the inner bearing race...thats why it appears to be worn out. That inner race had to gain some slack somehow...like the bearing wearing and allowing it to move or turn on the spindle. If you heard metal grinding...that was the race turning against the spindle...thats big trouble if it ground into it much. Fortunately spindles are easy to find used.

This was very helpful information. I have posted on two other forums right now trying to decipher my problem. Same metal on metal problem BUT the kicker for me is there is absolutely NO MOVEMENT at all in the bearing assembly. It is very tight. How is this possible if the bearing assembly is going out or if the race is rubbing metal to metal on the spindle? Wouldn't there have to be play? Here is what I've posted about it toward the end of this thread: http://www.corvetteactioncenter.com/forums/c4-general-discussion/124319-wheel-hub-bearings.html

 

[ocean]

as someone stated there is no room for tightening the wheel bearing. I eventually changed the bearings and an driving very confidentally now. with 145K do your Vette a favor and change the wheel bearings. you don't want a failure on the interstate or far from home.