bearing failure

[Chuck W.]

I thought I was done working on mules, but a friend had a massive bearing/gear failure on the right rear portal axle on his mule. Made a real mess, damaged the axle housing casting, the axle, all the gears and bearings and the cover. We are going to go ahead and replace the bearings in the other three housings.

[Guam0311]

Wow that's some massive damage Chuck, is that the Idler gear all chewed up? Must be some serious abuse to do that.

[Chuck W.]

hard to say what happened first. The owner does not abuse his mule, but it is a working mule on a farm and is used almost every day.

[Pack75howitzer]

Major damage.don’t know much about mules but I did look at an exploded view of the drop axle on line. With 3 gears arranged in a row like that a wobble in any of them would chew up the adjacent gear to start. Was there any play in the shaft from the transmission that could have been causing the driving gear to chew up the center gear ?

[Chuck W.]

I suspect that the inner needle bearing failed on the intermediate gear. I have seen the needle bearing on the outer end of the axle shaft fail several times, usually due to lack of lube or wrong lube (grease). This portal still had plenty of oil. John Emery had most of what we needed, although some of the cups and cones are getting hard to find. Mule owners might want to start stocking up on American made 13830 cups and 13889 cones.

[Chuck W.]

Making progress. Inner axle seal replaced, ring gear re-installed, RR axle housing replaced, frame tubes re-installed. Battery box re-installed, engine guard re-installed. Waiting on the 13830 cups.


Dang! Left the bathroom door wide open!

[Grummanflyer]

Good grief that looks like a lot of work

[Chuck W.]

It is, also very expensive. This failure is going to cost the owner in excess of $1000 in parts alone. I think it is EXTREMELY important to drain the oil from the portal housings and inspect for metal at LEAST once a year. By the time you hear noise, it's usually too late, the damage is done.

[Chuck W.]

Finally managed to round up a compete set of cups, cones, needle bearings and ball bearings for all 4 drop housings on Richard's mule. Here's my setup for checking/adjusting the bearing clearances on the half-shaft drive gear. Had to use a 3" extension rod on my dial indicator. After this, I'll set the king pin bearing pre-loads, then I can install new dust boots and send this puppy home!

[Grummanflyer]

How much end play are you looking fore here?

[Chuck W.]

TM says .001" to .003". It is adjusted by shims behind the bearing cup, meaning you have to knock the cup out each time to change the shims. Two drop housings I got right the first time, the 3rd one took 3 tries and the 4th one took 5 tries!

And a reminder, on the needle bearings, there is a front and back, the side with the larger radius goes in first. And use the correct driver.


And make sure the needle bearings are driven in far enough so that the oil slot is open, this is how the oil gets to the bearing.


More progress today, right side is done except for the oil.

[Chuck W.]

Making progress. Axle work is done, just left the tires off the left side to I can work on the wiring. I am installing one of John's boxes and switch.

[muleman]

Chuck has been very gracious to take on this project which was not in my skill set. My input was finding the bearings needed to refresh the mule. That took a lot of time looking on the internet. Bearings needed are not easy to find now. Chuck, along with others, was also a large part of the 4 wheel steer conversion of this mule many moons ago. That work is also posted on this forum. Big Thanks Chuck

[Chuck W.]

Finished up today.