Need help in identifying a pinion seal for my 50 Olds. Couldn't find anything when searching previous posts.
Can anyone give me a part number on a modern seal and what it takes to replace it.
Thanks,

 

https://www.fusickautomotiveproducts...?number=514066

Car safely raised on a lift or jack stands on a adequate hard surface. Remove driveshaft. Yoke nut comes off easily with a impact wrench and socket. There is a purpose made puller to pull yoke pressing against the pinion but really any center-stud puller can work, even a steering wheel or crank pulley puller with some trying. There also is a seal puller but you can just drive it out carefully chiseling from the edge of the seal lip. I start the removal using a old sharp knife prying under the lip. When removed, diff fluid will run out so be prepared for a small mess. You can let it drip and replace some of the diff fluid this way. The machined surface in the carrier should be clean unless the car was under or on water, check it after seal removal. Drive the new seal in with a large socket or piece of pipe, once again there is factory and aftermarket seal drivers for this purpose. Check the machined surface of the yoke which contacts the seal and make sure it is clean and not burred up, remove any rust. Yoke slides on with some resistance felt from pressure of new seal. There is a yoke holding tool like a long lever with four holes to fasten to u-joint bolt holes to make tightening the yoke nut to the specs easier, but I and many have had a helper hold the brakes and tighten up to spec this way. Replace lost fluid through pipe plug in diff casting, install driveshaft. Use mineral and hide based 90w gear lube, not any modern synthetics. You want the stuff that smells real bad, brown color. U-joints may have grease fittings to service those as part of the job.

One tip: The rear u-joint may use a 'mechanics' style u-joint which have machined bearing caps containing the threaded holes for the fastening bolts. Wrap a few turns of duct tape around the joint before removing bolts as those caps want to drop off the u-joint center on removal with the tiny needle bearings coming out even if greasy. Murder trying to find them all when they drop to floor or driveway or drip pan etc.

This procedure and torque specs are found in the factory service manual for your car, easily obtained. Work safe good luck

 

Nice write-up. I'll add don't over tighten the pinion nut, the goal is to put it back exactly where it was, not looser and not tighter.

Pack the spring cavity in the back of the new seal with Vaseline to prevent the spring from jumping out while driving it in to place.

Lube the sealing lip of the seal with gear oil

As mentioned clean and polish the outside of the yoke where it contacts the seal.

As soon as the driveshaft separates from the yoke, wrap the two needle bearing caps securely with tape so they don't fall off and start a needle bearing hunt...been there.

Good luck!!!

 

Thanks Coldwar. What is the part number of the seal? Is it a double lipped seal? I don't have the factory manuals. Can you give me the torque specs on the pinon nut and the U joint fasteners?

 

Thanks for the tips Sugar Bear. How do I know that the pinion nut is back in the same place? Do I have to clock it?

 

Look at the picture of the seal on Fusick - 49588? Doubtful you will find a quality part much less then $31. NAPA used to stock them even recently. I don't recall a spring on any Salisbury or hogs head Oldsmobile diff. The yoke bottoms on the spline ends for installed depth as I recall - Good luck

 

Coldwar, Isn't there a crush collar on the pinion shaft to set the pinion bearing preload?

 

Yes I'm sure there is I don't recall a spring like a Ford but getting old is cruel - I'll have to check - CW

 

Thanks coldwar...To the OP, the crush collar that limits the pinion bearing preload is why the nut shouldn't be overtightened. If overtightened the diff has to come apart and the crush collar replaced. Mark/index the nut position and count the exposed pinion shaft threads before removing the pinion nut.

Good luck!!!

 

You can get one here;
1950-1951 Oldsmobile Shop Manual (1951) Vintage RARE | eBay
The best investment you can make.

 

No spring. Memory soldiers on. Reference: 1952 Chassis Parts Manual, 1963 Motors Manual which I had open for another reason today and remembered the thread. I have many 1952 Service manuals but cannot find even one quickly Funny I didn't recall the flange bottoming at rest against the bearing.