Looking through my resto parts catalog, it mentions a 'Rear Axle Flange to Backing Plate Gasket'.

I don't recall seeing any of these gaskets when I pulled rear end apart. I thought the rear backing plate just mounted to the axle tube, 4 t-bolts/nuts... done. Am I missing something?

 

They are usually disintegrated by now,but they did put a very small/thin gasket between the backing plate & the tube flange.Not a real neccessity,but you can smear a little RTV in that area.

 

Gear lube will seep out onto the brakes if you don't use some sort of gasket, but like Brian, my "gaskets" come in a tube.

 

Those gaskets were never designed to hold fluid from seeping as you have a seal in the axle tube and or if you are using A9 the seal on the axle. Pontiac used a STEEL shim with NO sealent at all - gasket was to keep parts from rusting together most likely.

As Brian stated mostly not necessary in most cases.

Remember the oil WILL seep through the retainer around the axle pressed in surface even if you use a sealant...Please look at how it is all put together ... sealing this retaining plate will not stop leaks. Only your axle seal will.

Good luck. Jim

 

Jim is of course correct. I'll just add that I use RTV on the backing plate to flange joint to keep dirt out of the axle bearing. Admittedly there shouldn't be much, but driving through a rain puddle will splash dirty water up at the backing plate.

 

I just installed a custom 9" Ford rearend with Moser axles that use sealed bearings. I was instructed by the manufacturer not to use an axle seal, but to smear a little RTV on the outer bearing race and in the axle tube where it seats.

However, the '67 8.2 P-type rearend that it replaced had two on each side...one between the brake backing plate and axle tube flange and another between the axle retainer and the backing plate.

 

Regardless of what that gasket was intended for,it won't stop oil from getting on your brakes.If you have an oil leak,you have a bad seal,and it would need replaced.