Rear Wheel Bearing Lube

longld · Post by **longld** » Sun Oct 28, 2018 8:08 pm

53 M38A1
Completely rebuilding my rear brakes and while trying to figure out how to lube the rear wheel bearings discovered that that there was no zerc fitting. A little reading and after much cleaning, discovered the pipe plug, removed and installed a zerc fitting. Also discovered the vent at the top - based on reading, I assume this is to show you when you have put enough lube it the wheel bearing? Somewhere I remember reading that the military put the plug in there to prevent GI's from overlubing the bearings and causing lube to enter the brake area? That is confusing since the 'vent' should show you this. What am I missing?

So do i install the drum first and then lube until I see lube out the vent?

Did a search of the forum and couldn't find anything on this....

and....tried replacing eccentric's with parts from Kaiser - the shoulder (that extends thru the backing plate) is too high and it prevents you from locking down the nut on the backside - went to larger lock washer/flange nut and it worked. Anyone else had this issue?

Post by **wesk** » Sun Oct 28, 2018 9:14 pm

Vent hole is not for the bearing, it is for the axle housing. Only thing that should ever come out of that vent hole is gear oil.

longld · Post by **longld** » Sun Oct 28, 2018 9:54 pm

Wes,
Figure A is what I am talking about - part 587305. This seems to be in the same chamber that the zerc fitting is installed in - am I mistaken?
cheers, lee

well photo not so clear - fitting is far right on top of wheel, you can see the zerc fitting just below (item F, 5504208).

Post by **wesk** » Sun Oct 28, 2018 10:17 pm

My bad. I am thinking the 41 axle with two vents.

Here's a failsafe test. Take a piece of stiff wire and run it in each hole and examine angle and penetration length.

longld · Post by **longld** » Sun Oct 28, 2018 10:36 pm

thanks Wes, the Dana 41 pic clearly shows both holes go into the same chamber - never seen this photo before. and it clearly refers to it as a grease vent. Interesting that the official part manual lists both as 'fittings'. I wonder how many M38A1's have no grease in these wheel bearings?

skyjeep50 · Post by **skyjeep50** » Mon Oct 29, 2018 9:42 am

Back to how to grease the rear axle wheel bearings: Per TM9-8014 page 60 (Lubrication chart for the M38A1) - the rear bearings should be disassembled, cleaned and hand greased every 12,000 miles or annually. Most of us don't drive these vehicles 12K per year but greasing by hand annually makes sure they are properly lubed. Additional lube via the zerks between annual hand greasings is probably not needed if you're not putting to many miles on your Jeep. If you are rebuilding the brakes you're just a few steps away from removal of the bearings completely from the axle tube making it easy to complete the lube process by hand.