Replaced wheel bearings about three months ago. The right rear just went out again. Mechanic replaced the hub as well this time. The old one, instead of being shiny where the bearing sits, was discolored from heat. After replacing the hub and bearing he drove the car for awhile, then checked the temperature of the hub. Right rear hub was ten degrees hotter than the left. Not sure if that's important or not. Anybody run across this issue before?

 

ten degrees sounds like alot, but I would think in mechanical engineering, where bearings are concerned, or even brake rotors, the difference is probably a very low percentage. Old hub and new hub could have slightly different metal composition also, resulting in a difference in thermodynamic properties - ability to transfer heat. I wouldn't worry about the difference too much. What were their actual individual temps?

 

sounds to me like the bearing was too tight. there is a select thickness shim in there, probably needs a thicker one.

 

Just checked. Temp on right hub after driving an hour or so was 160. Left was 153. Mechanic said he was getting a 10 degree difference yesterday but mine is closer. Probably not enough to be significant.

 

Beauregard,
Wouldn't the shim be the same as long as it's the correct bearing?

 

shim thickness variations are on the order of thousandths of an inch. this is to account for spacer, hub, and bearing manufacturing tolerance variations. the shim goes between the bearings along with a spacer to set the proper clearance when the axle nut is torqued down. too thick and the bearings have too much play. too thin and the bearing is too tight and will overheat. there is a spec (don't remember)for the amount of play. you can easily check by raising the wheel off the ground and wiggling it back and forth. it should have a tiny amount of play.

 

Thanks. I'll check it.