031014 - The weather warmed up some this past week, and I decided to start the maintenance work on the drive axle. I pulled the brake drums, axles, and hubs, and disassembled the brakes. I found that one of the wheel seals had been leaking, resulting in oil coating the brake assemblies and shoes. This probably slipped past me because of the high degree of grease coating the axles primarily due to the lack of proper maintenance of the coach prior to my purchase, and the difficulty in washing everything thoroughly.
Teardown of the axle was pretty much the same procedure as the and
, except for removal of the axle itself, which consisted of removing the
nuts from the axle retaining studs in the end of the hub, and pulling the axle from the housing. Due to the high degree of
grease and grime coating the assembly, my hands, and everything else in the vicinity, I decided to forego taking a lot of photos
of the teardown. I did get a few, though.
I took the drums down to C&J Bus Repair to have turned. Ed, a once retired bus mechanic who had been called back to work due to high demand, did a thorough job on the turning. There was a flat spot in one drum, which resulted in the drum needing to be turned down until it measured out in the "once over" range (14 5/8" - 14 3/4" diameter) with regard to brake pads. The second drum was not as bad, and didn't need to be turned as much. I'll mount once over pads on that side, too, so I will have a matched set. I purchased new brake shoes, also, because the old ones had corroded beneath the pads. The new pads were installed on the new shoes.
I pulled the DD3 brake cans from their mounting brackets, and installed new diaphrams in them after cleaning up the corrosion
around the clamp flanges of the various housing pieces. The brake anchor pins were corroded, so new ones were installed.
New brake lines were installed as a precautionary measure, and the brake springs, retaining plates and cone wedges in the retaining
plates are also new.
While I had everything torn out, I decided to install new leveling valves, air bags, and shock absorbers.
The old bearings were not in bad condition, but I decided to install new bearings and races in the hubs as a preventive measure. I'll keep the old bearings and races for spares in case I lose one while on the road. New wheel studs were installed in both hubs, and new, longer inner lug nuts will be used to allow the use of aluminum wheels in the future, should I wish to go that route.
A new oil seal and gasket were
installed in each hub, and the axle shaft gasket and axle bolt cone wedges were also replaced.
The seal wiper on one side had a gouge in it from previous poor maintenance. This may have been the cause of the leaking
seal in the first place. Initially, I was going to try to repair it with some JB Weld, but decided to replace both of
the wipers. They had to be cut off with a cold chisel, and new ones pressed onto the spindle. I heated the seal in the
oven to about 150 degrees, to get it to expand, and slid it over the cold spindle and tapped it in place using the old
bearing. Using the old bearing kept the seal wiper straight on the spindle so it wouldn't bind. This worked very well.
When I replaced the wheel studs in the steer axle, I used a large hammer to drive the new studs into the hub. I started out using that same method on the drive wheel studs, and found that the smaller studs being driven into aluminum hubs did not take well to that method. I ended up damaging the studs. It appears the pounding caused the studs to compress and expand slightly, especially around the end where the threads begin. I ended up having to replace one of the new studs because it was damaged too severly to be used. The solution to this problem was to use a piece of pipe which fit over the threaded stud and contacted the flange at the base of the stud. The pipe was then used to drive the stud into the hub and no more thread damage occured.
While this work was a major drain on the budget, I justify it all through safety. Bringing a 30,000 pound coach to a stop in the mountains is not something I wish to play games with. It's my life and my family's lives at stake here, as well as anybody who happens to be in the near vicinity. As far as I'm concerned, this is no place to cut corners. There's only one way to do the job, and that's the right way! And doing it correctly now, means I should not have to do it again for a very long time. It's just a matter of performing proper routine maintenance work now; something this coach has seen little of before.
Here's some photos which belong in the air beam maintenance page...
The following is a partial list of part numbers used in this work: