mike brez wrote:
Was fooling around installing my trucenter and noticed oil on my inner dual. Smells like differential fluid. Guessing axel seal. Made a appointment for repair next Tuesday. Im a little nervous. This will be the first time sence rving (20 years) that I have had a shop do a repair besides tires and a front end aligninment. Sence I purchased this rv last year with no service records I changed all filters,oil and tranny fluid to transynd. I'm going to have them adjust slack adjusters,lube chassis change air dryer and check front end for any lose or worn parts.
Hey Mike,
First off, if it smells like "Diff" oil, it most likely is. Nothing in, on, or around that differential has any other kind of oil. If you've been around for a while, you'll know it's very distinctive. Second, YOU DO NOT HAVE TO PULL THE BRAKE ASSEMBLY! The hub systems have changed over the years but, without knowing just EXACTLY which diff you have, I'd bet my house that you do not have to touch the brakes. That is, if they're not soaked in diff oil. If they are, well, then you've got other issues to address.
But, if the axle is on the coach represented in your sig, it's most likely a Dana 70, 80 or larger. And that means the hub is separate from the drum or, disc, which ever you have. Based on year/model, I'd guess you have rear drums. The procedure is simple but, can get a tad bit technical. I know you said you're setup for an appt. for the repair but, here's the scoop.
1. Both wheels and tires (of the effected side) are removed.
2. The brake drum (or disc) is removed (most of the time, it's just onto the hub via being clamped to it by the wheels and lug nuts.)
3. The axle end bolts are removed
4. The axle can be a bear to remove, based on just how sticky it wants to be. On our fire trucks, we had to BEAT the ends with a 20 lb. sledge to get them to break the bond of the hub. But, not always.
5. Once the bond is broke free, the axle slips right out
6. Now, here comes the tricky part. The hub is held on usually by two different, VERY LARGE hub nuts. An outer one, which is used as a lock nut, for the inner one. Those hub nuts can be as large as 3" or 4", depending on the model of the diff used.
7. Various assemblies utilize different ways of clocking the lock ring, (a ring in between the two nuts) that is used to keep the inner nut from spinning, while the outer one is being tightened, to keep the precise bearing tension in place. If the company lets you watch the disassembly (which I doubt very seriously they will due to insurance regulations) you'll see how that entire assembly comes apart.
8. Once the outer nut, the lock ring and, the inner nut are removed, the hub will slide off the end of the threaded axle housing.
When removing the hub, the outer bearing will no longer have any form of support on the inside diameter so, it will basically fall out, if the hub is tilted down.
Now, if the tech knows what he's doing, he will have "tilted" the differential slightly towards the tires and wheels not being worked on. That will keep differential oil from flowing out the axle end that is being worked on.
From this point on, the hub is taken to a work bench and, the axle seal is removed. The inner bearing will now be ready to be removed for inspection.
Both bearings are now inspected and, so are the cleaned up race cones which are still installed in the hub. If no issues are found, the bearings can be used again. At this point, the inner bearing is re-installed into the back side of the hub and, the hub is prepped for the new seal.
I had to make a seal driver for installing mine due to the fact that, that seal is 5.5" in diameter and, was $36.00 so, I did not want to damage it during installation. It went in just perfect.
From this point on, all is reversed.
Now, the only issue that may have cropped up during this repair is, if the shoes are soaked with diff oil. I have used, various kinds of "Brakekleen" (a brand name for high tech cleaning fluid) that actually can penetrate brake shoes and, extract the oil that's impregnated into them. This, is a judgement call. And experienced tech can tell if, at a certain point, if the shoes can be saved or not. If not, you're up for a new set of shoes. If they can, all you're going to pay for is, a couple of cans of Brakekleen and, probably a 1/2 hour of labor. That remains to be determined and seen.
Well Sir, that's about the scope of it. I've done quite a few of those seals. Both on the rear and the front of these coaches. The front is very similar to the operation of repair as the rear.
Anyway, good luck and, please report back on the findings. Below are a few pics of my axle end etc. during the seal replacement of the drivers side a couple of years ago.
Scott
