Overheating left bearing 8-3/4 rearend

[Smokinnjokin]

Scratching my head, drivers side bearing is overheating after replacing on 8-3/4 axle.

Here's the details. About 15k miles ago, swapped pumpkins for a used 3.23 sure grip unit. Bearings looked ok, so I repacked and reinstalled. Have driven much since and the drivers side bearing burned up a few weeks ago. Pulled it before it totally came apart, but it definitely had some metal bits grinding. Read the sticky thread on here, Had a local shop press on some new national A7's, new wheel studs and greased bearings with Lucas green UHD. Followed endplay procedure (no dial indicator, backed off 4 tabs) and took it for a drive. Drivers rear wheel overheating. By my heat gun, getting up to about 375 at the brake drum. Other wheels all measuring around 100.

So I made sure the brake shoes were not dragging, double checked endplay again and backed off 4 more tabs just to be sure. Drove it again. Still overheating. Got up to 250 degrees on a short drive. Again, other wheels 100 degrees.

What gives? The only thing I can think of is that maybe the shop did not fully press on the drivers side bearing retainer, so it has no endplay? Seems unlikely, they are mopar guys and familiar with the 8-3/4 with tapered rollers. Or perhaps the inside of the axle tube was damaged by previous bad bearing (I cleaned it up, didn't look terrible). At this point, there's no way the endplay can be too tight, right? I guess next step is to pull the axle back out and have a look, maybe take measurements. This is a frankencar, so I have no idea if the axles are original, or even mismatched or out of spec. The fact that last time, only the left side bearing burned up as well has me slightly curious... I would assume both would burn up at the same rate.
This is really irritating, usually these tapered rollers are set and forget.

 

[R413]

Raise both rear wheels off the ground and on stands. Remove rear wheels and drums.

grab the axle flange and pull in and out with some force. Do you feel any end play? The end play should be the same on each side. So if one is tight they are both tight.

 

[66 Sat]

Did the shop pack the bearings properly with grease? Maybe the mechanic did one side and let the first week apprentice do the other side?

 

[Big Bad Dad]

Possible the axle is bent a bit?

 

[khryslerkid]

When installing the used center section were the thrust buttons still in place?

 

[Smokinnjokin]

Raise both rear wheels off the ground and on stands. Remove rear wheels and drums.

grab the axle flange and pull in and out with some force. Do you feel any end play? The end play should be the same on each side. So if one is tight they are both tight.

Just did, I felt end play on pass side axle but none on drivers.. which is strange they should both have end play if one does, right? Backed it off 4 more tabs and now I have end play on the drivers axle as well. Now im backed off 12 total castellations from when the adjuster was all the way tight. Maybe I overdid it tapping it tight with the mallet and screwdriver. It does not spin freely takes a bit of force.

Did the shop pack the bearings properly with grease? Maybe the mechanic did one side and let the first week apprentice do the other side?

They looked properly packed... can't pull back the outer race to see really once they are pressed on but I assumed they were...

Possible the axle is bent a bit?

I just noticed when doing the above procedure I have a lot more radial play in the left axle then right. Could be a bit bent.. tearing up bearing prematurely.. will definitely check if I have to take it back out.

When installing the used center section were the thrust buttons still in place?

It's been years since I swapped... don't recall checking for it but if it didn't have one wouldn't the left axle be totally loose with no endplay adjustment instead of too tight?

 

[33 IMP]

My first thought: either the axle or the housing is bent.

 

[Smokinnjokin]

Ugh… if so i really hope its the axle not the housing.

 

[Smokinnjokin]

Is there a way to measure or tell that the bearing retainer is fully seated on the axle? Im thinking that if the drivers side axle bearing wasn't fully seated, it would cause my issue... Going to pull the axle tomorrow just trying to figure out how to tell if it is not seated fully. I have lots of endplay right axle and barely any on the left.. which does not make sense with how they are supposed to float. Something is limiting the travel of the left axle. Hence my thought it is the bearing not fully seated.

 

[Smokinnjokin]

OK so the plot thickens. I think the brakes are the source of the heat. After a test drive today, I immediately popped the wheel off to check everything out hot. There was endplay in the axle (too much, really, probably from all my caution earlier) and the heat source seemed to be the shoes. They were 300 degrees, the axle and bearing area of the axle tube were much cooler, around 190-200. Which would seem to indicate to me that the brakes are the source of the heat, not the bearing.

Here's the thing, I can't get them to drag at all with the car jacked up, wife pressing and releasing the pedal, everything seems fine. The shoes are wearing evenly, the brakes are bled and feel great, drum spins freely with no sound or resistance.... What gives! Why is this one wheel getting so damn hot?

 

[Big Bad Dad]

Have you actually checked the axle for bent yet? Jack the car up with the rear on jackstands. Put it in gear with engine running and watch to see if there is wobble in the flange. Do this with the brake drum off so you can see the flange. Then do it again with the brake drum on to see if the drum is warped. Also, it sounds like you have really got your endplay adjustment way out of where it should be. But you also may be right that the bearing and retainer are not seated. Work your way back through it.

 

[dadsbee]

My Bee's end play adjustment was easy as hell. I had a bitch of a time getting the rear axle I built for the '64 to settle in to an acceptable end play. Beat on it and make sure it's actually good. After that, back that set of shoes WAY back off the drum and go for a drive trying to stay off the brakes the best you can, then see what you have.

 

[Smokinnjokin]

Have you actually checked the axle for bent yet? Jack the car up with the rear on jackstands. Put it in gear with engine running and watch to see if there is wobble in the flange. Do this with the brake drum off so you can see the flange. Then do it again with the brake drum on to see if the drum is warped. Also, it sounds like you have really got your endplay adjustment way out of where it should be. But you also may be right that the bearing and retainer are not seated. Work your way back through it.

Great advice. I did that and the axle flange was completely steady, no wobble. Clearly the axle is not bent. With drum on, no warpage evident.

My Bee's end play adjustment was easy as hell. I had a bitch of a time getting the rear axle I built for the '64 to settle in to an acceptable end play. Beat on it and make sure it's actually good. After that, back that set of shoes WAY back off the drum and go for a drive trying to stay off the brakes the best you can, then see what you have.

I guess this is my next troubleshooting step. Back the shoes way off and drive it again. I mean, I guess it's possible that the hot brake is working perfectly but doing all the work because the other 3 sides shoes are backed off too far?

 

[Fran Blacker]

Could it be a self adjuster over adjusting and making brakes drag.

 

[dadsbee]

This all said... years ago I use to have my passenger side rear drum get so hot that the thing would basically seize up if I didn't remember to stick my toe under the brake pedal and lift it up. Master push rod just a BIT too long and not allowing the brakes to back off fully.

 

[Smokinnjokin]

I will report back tomorrow, thanks all for the help.

 

[Smokinnjokin]

Sure enough, when i backed it way off that wheel cooled down. Brake was working perfect, it was doing ALL the work. Hard to tell with a sure-grip and fat back tires, tracked straight under heavy braking.

 

[Smokinnjokin]

Thanks all for the help. Set the endplay properly (same way I did first time!) and after a long drive and lots of brake stops, checking brakes temperatures and adjusting, have the brakes balanced nicely. about 180 degrees on the front drums and 160ish on the rear drums after heavy braking. This would have been very, very hard to diagnose properly without the IR thermometer. Love that thing.

 

[dadsbee]

Glad it worked out. What makes this place great is the bin Der dun Dat and the willingness to share!

 

[eldubb440]

Glad it worked out. What makes this place great is the bin Der dun Dat and the willingness to share!