what is causing wheel bearings to overheat and score the race?

[bhawk]

About 6 months ago, our 94 ranger 4x4 got a growling noise from the front end. I discovered the inner race on the rotor had a little chip out of it. So I removed the race, installed a new bearing and race and the noise went away. The bearing had evidence of heat damage, kind of reddish color in a couple spots. Anyway, yesterday the growl came back. So I pulled the same rotor off and discovered the outer race had a chip out of it and the bearing had heat discoloration.
I'm thinking the caliper is sticking causing the rotor to overheat and the race is the first piece to fail. What do you think?
By the way, I am very careful installing the bearings and follow the service manual precisely when I torque the bearings to spec. Warn manual hubs by the way. So I have to rule out overtightening the bearings. Anything else that will cause the bearings to heat up and fail on the same side, twice?

 

[jhammel85]

Sounds to me that you are putting the locknut on to tight. Are you torquing them to spec, then backing it off?

 

[bhawk]

I'm torquing the lock nut exactly like the service manual says, which from memory includes backing it off as you say.
However, from reading old posts, I think I may have found my problem. I think the brake pads are hanging up on the spindle knuckle and not retracting as they should, causing the shoes to be tight to the rotor and overheating it. The cast knuckles have pockets worn into them from the pads moving back and forth while braking. Apparently this problem is not uncommon on the 94 Rangers and Ford fixed the issue in 95 by changing the caliper attachment and slide system. But that doesn't help me. I am going to try and find better knuckles off a parts truck at my farm. If that doesn't pan out, I may get my son, a welder, to lay some weld on the pockets of the knuckle, grind them smooth so new pads will slide properly, and hope the weld holds on the cast knuckles. I'll report back on our success or lack thereof in due course. Thanks for your post.

 

[AllanD]

To permanantly fix that problem you need to find a 1995-97 Ranger in the junkyard to steal the knuckles and calipers off of.


though someone who is a real artist at welding cast iron could weld up those knuckles

Makes me wonder what my grandfather could have done with a couple sticks of hard surfacing rod....


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