M101a2 wheel bearings question

[TITANBOW]

I have been procrastinating and never got around to redoing my bearings. We finally took the trailer up for a family camping trip this weekend, about a 3 hour drive from home. We made a couple stops for fuel/ bathroom breaks, and each time I would check the hubs with my hand to see if they were getting hot. One side was definitely a little warmer than the other, but neither felt too hot to touch or leave your hand on.
The fact one side is a little warmer than the other any reason for concern?


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[juanprado]

Bearings and seals are common civy items you can get at any parts store. Dive in and check them.
Could be as simple as checking spindle nut adjustment. Tire pressure low or tire issues could also be the culprit.

 

[topo]

Right now they may need only grease and on the side of the road they will need more then just grease or even loosing a wheel in traffic would be pricey .

 

[Zed254]

When I recovered my M1101 from Bragg the spindle nuts were too tight. I ended up stopping at every rest area on I-95 from Bragg to Virginia Beach to let the hubs cool down some.....because I did not have the correct sized wrench to get into the bearings on the return trip. Once home I checked them out: lots of brand new grease, but spindle nuts way too tight. Like Juan says, check them. Could be an easy fix like mine were.

 

[TITANBOW]

Thanks for the replies. So one question I have. How do you know when something is wrong? If you place your hand in the hub after you have been driving, is it ok that it is warm just not hot to the touch, or should there be no heat build up there at all?


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[Mullaney]

Thanks for the replies. So one question I have. How do you know when something is wrong? If you place your hand in the hub after you have been driving, is it ok that it is warm just not hot to the touch, or should there be no heat build up there at all?


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Very little. Warm is the key. One of those "temperature (heat) guns" would be a good tool to have. Red dot to aim it and squeeze the trigger for a temperature reading... That way you can compare left and right sides and maybe +/- ten degrees or so between the two. On a boiling hot day hotter and freezing cold it goes the other way.

You shouldn't feel like your hand would get burned if you touched the hub.

Normal could be 80 or 90 remembering the ambient temperature. 115 to 125 after a couple of hours and maybe 150 to 160 after about four hours with a little load (weight) on the trailer. After about 150/160 you should start to be a concerned.

 

[Barrman]

Which side was the sun on? I second the IR thermometer gun idea. I use mine to check every bearing and tire. If one isn’t like the others by a little, no problem. By a bunch and I start to look into it.

 

[DeadParrot]

A bit harder to check but might check the brake drums. Possible the warm side is dragging just a bit and warming the hub.

How to properly tighten bearings seems to be a mostly lost art. One side on my 101A1 had been tightened to the point of starting to collapse the bearing cage.

 

[gringeltaube]

One side on my 101A1 had been tightened to the point of starting to collapse the bearing cage.

WOW, really!? How could that even happen...?

 

[Floridianson]

Wonder since most roads are crowned and driving in the right lane the passenger side might get a little hotter. That and if you loaded the passenger side of the trailer heaver plus crown might heat up that side?

 

[DeadParrot]

WOW, really!? How could that even happen...?

View attachment 841112

The trailer came off the Norman OK guard base via a GL auction years ago. When I pulled the hubs to inspect I found fresh grease on both sides. One side had bad races. The other had new races and a bearing with a bunch of the cage bars bent out enough that they were slightly rubbing on the outer race. After a little gentle work with a punch, I had the bars bent straight and reinstalled the bearing. Didn't see any marks on the new races. Over tightening is my guess as to how a bearing wound up that way short of someone installing a visibly bad bearing.

It also had two tires that looked brand new. They are treaded tires and not the more normal NDT. Still had the nibs on the tread. They had tossed a third tire and rim in the bed. That one was a NDT with a date code from the 60s. The trailer had also received the newer style lights at some point.

 

[gringeltaube]

............ someone installing a visibly bad bearing.

Yes, most likely the very same genius who left the bad races alone and just added fresh grease....! IMHO

 

[Mullaney]

Yes, most likely the very same genius who left the bad races alone and just added fresh grease....! IMHO

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Yse sir. I imagine the same genius that dropped the wheel bearings on the cage, picked it up, dropped it again or something like that. OR somebody had a case of the "Red A$$" and thought beating the retainer with a hammer would be funny... Other than that, like you gringeltaube , I can't see how the cage could be damaged.

Pitted races are one of those things. A slacker will sand off the rough spots. A jack-leg mechanic will pack it with grease to hide it for the next guy. The OWNER of the equipment will knock out the old and replace it with a new one. Odd how that works...