Paper Axle Gaskets

[w30bob]

Hi Guys,

From the M's I've looked at at shows this year, and some I've seen online, it seems many have weepage around the axles where they bolt into the front hub or rear. Then I ordered some hub/axle gaskets and I come to find out they're made of incredibly thin paper.......or something like that. You look at the darn things wrong and they break. Is it just me or is paper not a great gasket material? They look so thin I'd be afraid not to use at least two on every hub instead of only one. I haven't seen anyone advertise these gaskets made out of actual gasket material.......so what gives?


hubgasket by w30bob, on Flickr

regards,
bob

[k8icu]

Paper is a gasket material it was the material that met the needs for the manufacture at the time of design. Besides MVs love to mark their territory...

[neverfinished]

Just throw them away and use a thin layer of RTV silicone. No more leaks.
Ted

[Brett]

Bob
Those thin gaskets are the appropriate material for that application. The thickness of the gasket material should be inversely proportional to the quality and operating conditions of the mating surfaces. For instance, oil pan gaskets are typically quite thick and flexible, because the pan can't handle much clamping force without lots of deflection. Thermostat housing gaskets are much thinner than those for an oil pan. This is because we are now dealing with two cast iron parts with machined surfaces. this particular gasket is still thicker than those on the axle flange. That is because you have a similar surface area compared to the axle flange, but only 2 bolts to apply clamping force versus the 6 bolts on the axle flange. There are also more thermal changes taking place on a thermostat housing than an axle flange.

The other thing to consider is that thicker gaskets on the axle flanges would allow for more movement between the hub and the axle. This would be twice as bad on the rear axle as two gaskets are used because of the outer oil seal. That extra movement could lead to broken studs as torque is repeatedly transfered.

If you are concerned about getting a good seal with those thin gaskets, you should remove the studs. You can then be sure that all the old gasket material is removed, and remove any surface irregularities with light use of a flat file. Its pretty common for the surfaces to get scarred by the use of pry bars etc. Then clean every thing with solvent. I also like to use a gasket sealant like Permatex High Tack on paper gaskets.

If you do it right you should get a good leak free installation

Brett

[pwrwagonfire]

On the civi PWs I work on, we just use RTV silicone...no leaks!

I used paper on my M-37 just to see how they hold up.

These trucks like to let their rear-axle seals seep in hot weather when they are working hard

[skinnedknuckles]

I use Loctite 515 gasket eliminator on all of the axle flanges here at my shop including my m37 and I have had good results with it. Its a little pricey but a tube will go along way when you use it sparingly. It cures when its confined and oxygen is depleted, and it will stay "liquid-jelly" when exposed to air.

Paul