iner front and rear axle seals

[sixbysix]

A query for everyone.
my truck has been sitting up for a while and after taking it for a run a week or two back I have noticed what looks like gear oil running down the side of the wheel on all 6 wheels but most severe on the front wheels. I am thinking this is most likely due to leaking inner axle seals.
Question: are these likely to seal up with a bit more driving or is replacement necessary .... and if so a modern seal number part would be appreciated .....

[mudflap]

Sixbysix,

Does yor truck have Timken (split) or Banjo Axles ?

Best Regards..

[sixbysix]

Sorry I left that out - it has Banjo axles

[sixbysix]

.... and the oil is leaking down the inside of the wheels

[mudflap]

Gear oil has to take a fairly circuitous route to make it from the inside of the axle housing all the way to the wheels. It basically has to go through the hub and wheel bearings. The odds are that if the leak is bad enough to make it this far, there is already a fair amount of oil in both the bearings and the brakes. So, even if the seals could heal themselves with a little driving, it is still a good idea to start pulling hubs and drums to see whats going on.

The banjo front end has the small seal at end of each axle tube, that keeps the gear oil from running past the axle shaft. When I replaced mine, the good Dr. Deuce recommended a thinner seal that allowed two seals to be installed in the place of the one original seal. This moves the sealing surface(s) on the OD of the axle shaft to an area that is not as worn. I used Timken PN: 353141. You will need four to do both sides.

The front grease seals are available from NAPA - PN 36220 I had some issues installing these as they rubbed the base of the spindle until I drove them a little deeper into the hub (see previous post viewtopic.php?f=1&t=5524.

The rear grease seals are also available from NAPA - PN: 31870.

The gear oil in the rear axle is kept out of the rear wheel bearings by the outer seal, which basically seals the outer wheel bearing nut to the inner surface of the axle shaft. A lot has been written on this forum and others about the inadequacies of this design. Be that as it may, Frank von Rosenthal has them (or at least had them last year) GM PN 3660091. Rex Ward would probably be a good source as well.

Although they are part of the outer wheel bearing nut, they are serviceable and can be separated from the nut if you are careful. National also has a seal that fits and is readily available (PN 6090S), however you will need to do a little work on them as once they are installed in the outer wheel bearing nut, they cover the notches that engage the wheel bearing socket. A little work with a file or Dremel should take care of it. There are a number of posts on this site that contain tips on installing the rear outer seal and checking clearances.

Lastly, as has also been mentioned before, make sure to thoroughly check the axle vents. I seem to recall a post by Dr. Deuce that talked about replacing them with modern GM plastic vents. Not sure how long ago that was. I would like to hear how that has worked out.

All of the above are made of modern materials - i.e nitrile.

Best Regards..

p.s. One of the best kept secrets on the internet is the PN cross reference right on this website: http://cckw.org/part_number_cross.htm. I sometimes forget about it since my bookmark takes me right to these pages..

[sixbysix]

Thanks mudflap - looks like I've got a bit of work to do
will keep you posted if I'm having trouble

[dr deuce]

On my banjo cargo truck, I have dual front inner axle seals and shoveled in (literally) grease into the knuckle and new seals. I have the plastic vents and the front end is neutered with dummy hubs. That all works works well. Eventually, it will leak if you drive a lot like I do (~2,000 miles/year)

There is a gear oil, cornhead or something like that that is thick until moved. It might be an idea for the front axle if it is neutered. Mine only turns during parades because of low range usage for the slow driving.

[sixbysix]

Dr D
could you tell me a bit more about the plastic vents - and why these are better than the vents I already have .... and also if I wantr to keep my vents as is whats the best way to about keeping them clean and unclogged

[dr deuce]

I am NOT sure about this: The originals may have been the type that keep a little pressure on the housing to keep moisture out MAYBE. Not sure.

Every time I have removed the original ones and tried to blow them out by mouth, they are clogged. I use to just see if the cap wiggled and called it OK.

As I said, I am not sure about the originals. I am sure that others, probably Ranger know fer sure.

BTW, the plastic GM ones just force screw in. They have no threads, but pushing them down while turning them and they get the idea...

[sixbysix]

Thanks Dr D
I have been just doing what you used to - wiggling the caps a little.
BTW after taking the girl for a 1 hour drive ( after first checking the brakes) everything seems "sealed up" again - no leaking - at least not at the moment