The Stovebolt Site Forums The Shop Area Driveline 1956 3600 Rear Axle

Mine developed a leak at the pinion seal after I cleaned it up.

Who manufactured these axles and what model are they? It is a full floating axle with removable third member and bolt on pinion/pinion support. It looks similar to sterling axles I have seen but I have also seen mention of an Eaton on these boards?

I need a new pinion seal and pinion nut (I'm assuming they are torque to yeld?). Any leads for me on seal part numbers?

Also, does the pinion use shims or a crush sleeve to set pinion bearing pre-load? And what torque does the new nut need? I'm assuming this axle is like every other that I have worked on (ford 9", dana 44, dana 60, 14-bolt) when it comes to replacing the pinion seal.

1-remove drivehaft
2-remove pinion nut
3-remove yoke
4-pry out old seal
5-install new seal
6-install yoke
7-install new pinion nut, torque to recommended spec and/or reading bearing pre-load with torque wrentch
8-install drivehaft


Any help is appreciated. Thank you!

Welcome to the wonderful world of the Eaton HO 52 rear axle. No, it's not like a Ford, Dana, or anything other than a Peterbilt or other big rig axle- - - -just downsized. The seal is carried in a cast iron housing behind the pinion ,so once the flange is removed, the seal carrier can be pulled off and the seal can be changed on the workbench by driving the old one out and installing a new one. If you find the pinion nut loose after removing the driveshaft you're dealing with worn pinion bearings, so replace them along with the seal. The design of the rear end allows the pinion and its bearings to be removed from the front of the housing without disassembling the rest of the axle. If the pinion bearing is the double ball type, just get the nut tight- - - -there is no preload adjustment required, and no crush sleeve. The double tapered bearing design needs shims and a preload procedure- - -check a service manual for the proper procedure on that one. I doubt that the 56 model axle will have tapered rollers on the pinion.
Jerry

Anyone else?


I can not get the damned pinion nut off? The copper pin was rusted in place. I snips the ends off and it doesn't seem to be interfering with the nut any longer. I managed to get the pinion assembly out of the truck by removing the flange but still can not get the pinion nut to loosen. It isn't reverse thread by chance is it?

Nope- - - -it's just being locked by the remains of the cotter pin. Take a 1/8" drill bit to the cotter pin and get the rest of it out of the hole, or use a pin punch and a big hammer to drive it out. I'd prefer to drill it out. Then grab the pinion flange in a BIG pipe wrench and brace it on the floor while you use a 3/4" drive socket, a breaker bar, and a couple of feet of pipe to loosen the nut. Last resort- - - -heat the nut with a torch and apply lots of penetrating oil. It's not uncommon for those pinion nuts to have 200+ ft/lb of torque or more.
Jerry

Yeah I've often wondered how one can ever get them back that tight again. I guess they make bigger torque wrenches....

John

Thanks for your help Jerry. After some considerable time, effort, a lot of heat and some four letter words I got the pinion nut off. It took a 4 foot cheater bar and an oxy-acetylene torch but it finally moved after I drilled the cotter pin out.

I then had to use a 10" 3 jaw puller and some more heat to remove the pinion yoke from the pinion splines. It was a bear of a job but its apart now and sitting in the parts washer. The bearings look good and the pinion gear as well. I ordered the two pinion seals and a new nut and will put it all back together next weekend. Hopefully it won't leak for another 58 yrs.

I also broke a 24" craftsman breaker bar in the process. That sucker was really on there.

Several years ago my boss and I tried to rebuild the power divider of an Eaton 15-speed final drive in a 68 Freightliner. The input flange had a 2 3/8" hex nut. We broke two 3/4" drive flex handles and finally had to split the nut with a chisel. The assembly torque on that nut was 1200 ft/lbs.!
Jerry

Where did you find a new nut for sale? I haven't seen that offered.

I see your problem is solved but this might help out the next
guy. I bit the bullet and made the investment in one of these
a couple of years ago. Nice tool to add to your tool box:
http://www.harborfreight.com/34-in-professional-air-impact-wrench-68423.html
1400lbs torque, one very short burp on the trigger and it's
never failed to break the pinion nuts loose.

Denny Graham
Sandwich, IL

I ordered the nut (and seals) through my local Napa. I'm not convinced its the right part. Ill report back after I get it in and compare

I couldn't get mine loose seven years ago when I was putting the truck together. I took it to a garage and had them replace the seal. In the mean time I purchased a really cheap 3/4" air unit. I now need a new seal so today I pulled out the 3/4" unit and tried it out. That thing didn't have enough torque to undo a screw in a watch movement! It is a complete piece of junk! I went to the local rental unit and got a 3/4" electric impact gun. It is a Hitachi W-22. The nut came off in a second!