According to my mechanic, the rear axle seals on my '67 are leaking. So there is differential oil on my rear brakes. I'm in the process of replacing all the rear brake hardware, but I've never changed rear axle seals before. Don't even know where exactly they are. Are they are the rear wheel/hub? Or somewhere in the axle tubes?

I'd really appreciate a step by step on this one. Also, will I need any special tools?

The seals are located at the ends of the axle housing, where the brake backing plate bolts to. You must remove the diff. cover, drain the rear gear lube, and then you can get access to the C-clips that hold in the axle. One side at a time, push in on the axle, remove the c-clip and pull the axle out of the housing. Remove the brake backing plate and then the old seal. Replace with a new seal and inspect the bearings and axle for any damage. If everything is original, I would take this time to replace the wheel bearings. Reassemble is the reverse and same for both sides. Refil the rear with new lube.

Thanks Codi. When you say "push in on the axle", am I actually pushing the axle from inside the differential? Or am I pushing it from the end at the brake backing plate? Definitely pulling it out has to be from the backing plate. Also, at which end of the axle is the c-clip located?

...The C-clip is located on the end of the axle inside the differential.

I would anticipate replacing not only the axle bearings but possibly the axles themselves because the GM C-clip design uses the axle surface as a wearing surface for the bearings. Back when this design was implemented; rather than spending the needed buck and a half for a bearing race as they should have, they decided to flame harden the axle (actually was heated with a high frequency transformer) to let the roller bearings wear down the axle. As the axle self destructs it will sag into the seal wearing it away as well which is a common cause of the oil leak.

Many auto parts stores sell what are called axle saver bearings. These are bearings with an offset to wear on a different place on the axle but I don't recommend them for two reasons. First they have a smaller bearing surface area which accelerates wear by concentrating the force on the axle surface. Secondly they are wearing on a portion of the axle that was further from the location of the flame hardened area of the axle designed to support the bearing.

If you ever intend to race the car or just want the cool decal on the end of the custom axle for car show purposes now might be the time to think about aftermarket axles which are stronger than stock but do not wear any differently if you retain the old C-clip axle bearing.


Larger Dave

If I go with stock, how much are new axles, seals and bearings gonna cost me?

Let me add something to the instructions above. After you remove the cover and let the oil drain out you must remove the retaining bolt that holds the cross shaft in the differential. With the cross shaft removed then you can push the axle in to remove the c clip. With the c clip off then you can pull the axle out. There is no need to remove the brake backing plate to get access to the axle seal or bearing. Replace the bearing and seal, and as Dave said, you will probably be replacing the axle too. If there is any wear on the axle it should be replaced. Axles are $170 a set, studs are $20 and bearings and seals are $20.

And don't forget to put a bit of good old Permatex, Indianhead Shellac Gasket Cement on the ID of the housing end where the seals fit to stop any would-be weeping, however slight!!

And one thing that WILL cause seals to leak is a plugged housing vent! Heat create's pressure that isn't relieved so it pushes lube past the seals in extreme cases!

My old P/U did it..

I had at least a full cup of crap inside each drum to clean out!!

I bet there's still 200 pounds of mud and such under it....

pdq67

Axles... If you can not afford new axles I do have some good ones hear too. If that helps the pocket book any. I know some people are just cruising and do not need the heavy duty equipment.

I hope you have all the info you need to do the job. If you need at the moment help call 1 216 464 2313 x240 weekdays 10 -5 always there to help.

Make sure you keep the axle seals square in the hole when putting them in. Keep them flush with the axle tube end and grease the rubber seal well or you will be doing this all again real soon....lol. Take care and good luck, Jim

On the axles, for a few dollars more you can get good axles. Oh, don't forget if you have a posi, be sure to add the GM additive first.