Leaky Rear Axle Seal

[Hahn007]

Hi all,
1985 Dana 70HD drive axle inner wheel bearing seal is leaking pretty good.  Not sure yet if it's just a failed seal that's causing the leak, or worn/loose wheel bearings. I'm going to dive into it this weekend and find out.  I'm rather hesitant to work on a full floater as far as pre-lubing and adjusting the the wheel bearings is concerned (had a bad experience in the past).  Also not real clear which set of specs to follow in the service manual (using manual available from this site).

Any tips, advice, etc would be greatly appreciated.

Thanks in advance,
Chris

[Rickf1985]

A full floater is no different than setting front wheel bearings. Are you sure the differential breather is not clogged? That will cause pressure to build and leak out the seals. It is not a hard job, it is a heavy job so watch your back if you have a bad back.

[EldoradoBill]

Just did both sides on mine...leaky seals means new seals and shoes, and wheel cylinders while you're in there. Keep a rag in the axle tube until you're ready to reinstall the axle shaft-don't want oil on the fresh parts. If it's been leaking for a while get the drums turned, the oil has soaked into the iron and it won't come out with brake clean alone. Knock the seal out from the outside in with a wooden dowel so you don't mess anything up. If the surface of the housing the seal rides on is grooved you can get a sleeve kit from the parts store, you tap it on, peel the shoulder off like a sardine can and good as new. I always pack the inner bearing with grease when I reassemble so it doesn't run dry until the oil works its way up there; the grease will eventually melt and won't hurt anything. Don't overtighten the nut-snug it up with the special socket (under ten bucks at the parts store) then back off to the next closest lock or tang or slot or whatever yours has. Good luck, and eat them Wheaties lol


Bill

[Hahn007]

Thanks for the replies and tips thus far Rick and Bill.

Any idea what size the axle nuts are?

[EldoradoBill]

Tomorrow I'll get a photo and part number for you of the tool


Bill

[Hahn007]

Thanks Bill I really appreciate that.

[EldoradoBill]

Well as usually happens plans change   and I didn't get home tonight until well after dark; I'll get that pic up in the morning.


Bill

[Hahn007]

Sounds good.
Planning on tearing into it tomorrow.
Thanks again.

[EldoradoBill]

NAPA 2770


Bill

[BrianB]

Another brand/option - Performance Tool W1270.

By the way, neither Autozone nor Advance carry a 6-lug tool. All they carry are the 4-lug sockets.

[BrianB]

According to the service manual, when you put it back together:

"Tighten the adjusting nut while the hub is rotating to 50 ft-lbs. Make sure the bearing surfaces are in contact and then back the nut off 1/8th turn."
"Install lock washer and bend tang over a flat of the adjusting nut."
"Install outer nut and tighten to 250 ft-lbs. Bend a long tang of the lock washer over a flat of the nut."

[EldoradoBill]

I've had my socket a number of years. Wasn't even sure if NAPA still carried them.


Some bearing retaining nuts lock with a square key held in with a spring clip (like mine did). Had to magnetize a thin punch to get the key out...


Bill

[Hahn007]

Thanks for the part Number for the socket, worked perfectly.  Parts store was useless trying to figure out which socket on their own, even with the gm tool number listed in the manual.

I will double check the manual, but I think the 250 ft lb torque mentioned above is for the axle with the non tapered rollers.... The tapered roller bearing torque was much much lower.

The job went fairly easy and trouble free.  Thanks for all of your support.

[BrianB]

I will double check the manual, but I think the 250 ft lb torque mentioned above is for the axle with the non tapered rollers.... The tapered roller bearing torque was much much lower.

If you read closely, the 50 ft-lb is for the inner nut, and the 250 ft-lb is for the outer nut jamming against the inner nut and lockring. So you still only have 50 ft-lbs on the bearing.

[Hahn007]

Take a closer look. You are mixing two different specs.
There is one spec for the 10,500 lb and under dana and saginaw axles.
There is a second spec for the Rockwell 10,000 lb axles too.
The lighter duty axles use tapered roller bearings and the heavier duty use barrel roller bearings.

[Rickf1985]

I have never sen a Rockwell under these motor homes. And the spec is torque to 50 and back off a eighth turn and then put in the locking washer and torque the outer nut to 250.lb./ft. The idea is that when you tighten the jam nut it pushes the inner nut tight against its threads and preloads the bearing. I hope you did not leave 50 ft/lbs. on the inner bearing! I don't think I ever get a full 250 on the outer nut, I put a breaker bar on it and lean on it good so probably around 200. I have done many vehicles and never had a problem.

[Hahn007]

Section 5-2 in the online manual lists the Rockwell axle as well as both types of bearing types and two separate procedures.  I followed the specs and procedure for the Dana 70 and tapered roller bearings.