Rear axle oil seals

[Ghoste]

This is the simplest question I could ever ask but I am having the worlds biggest brain fart right now so here goes.
8.75 rearend, inner axle oil seal,  Not the one that sits on the axle with the bearing but the one that sits inside the axle housing.  If you picture it as a cup, which way do you orientate the cup?  Would you place the open part of the cup facing towards the tire or towards the differential?
I should know this but I am drawing a complete blank and there is a good reason why I'm asking.   

[Hot_Rodder]

Looks like we are in the same boat, I knew the answer for sure, until I read the quesiton... Anyway, I ahd to replace mine that was on my old '69, if memory serves correct, , then the flat side faces the tires.... May want to wait until someone confirms this though, lol.

[firefighter3931]

I should know this but I am drawing a complete blank and there is a good reason why I'm asking.   

I'm not telling ya ! 

Keep thinking ! 



Ron

[Ghoste]

So you don't know either?

I'll tell you what has me stumped Ron.  I had a very slight leak on one side so I ordered the seal and pulled the axle.  The axle shaft is not noticeably worn and the old seal looks perfect.  It should, I just changed it a couple of years ago.  Ordinarily, I would think a seal like that would have the bottom of the cup go into the axle housing so that it could be firmly seated in the bore.  However, having it with the cup in makes removal MUCh easier.  The seal looks perfect so could I have installed it backwards last time?  There are no rotational grooves so I can't even figure that into it.
Sorry, this one has just screwed me.  I've changed them before and I am just totally stumped this time.

[firefighter3931]

Think of your timing cover seal and front drum brake seals.....which way is the cup facing ? 


Ron

[Ghoste]

I haven't changed front drum seals in years and years  .  Timing cover is cup in, so... cup in, the way the old one is.

And THANK YOU!!!!!

[Chatt69chgr]

you want to pressure of the differential oil to push the seal against the axle and "seal" it.  you don't want it to open the seal.  but the timing chain cover example is a good one to help visualize what to do.

[Ghoste]

Which makes sense now but when I had a slight leak and I opened it up and the first thing I saw was that the old one (which is only a couple of years old) appears to be in excelent shape, the first thing I thought was that I must have installed it wrong.  That's when I totally brain dead and just couldn't access the information.  I don't know, some kind of summertime brain shutdown? 

[chargerbr549]

I would check to make sure the vent isn't plugged on the housing, that could be causing your leak, also check to make sure the seal isn't driven in the housing too far and not sealing on the shaft, which is what happened to mine, the factory tool to install seals must have squared it up and set it at the right depth, I just took my dial calipers or a tape measure would work and make sure that the depth on your seal is right, I lost a lot of hair and stressed out trying to figure out why the rearend kept leaking, but all is good now.

Kevin

[firefighter3931]

I haven't changed front drum seals in years and years  .  Timing cover is cup in, so... cup in, the way the old one is.

And THANK YOU!!!!!

You're welcome buddy....sorry to make you "think" too much...i was just funnin with ya. 

Dang, i hate those brain farts....if it's any consolation ; you're not alone. 

Thanks to the other fellows who chimed in 



Ron

[Hot_Rodder]

Looks like I remembered right,  . Sorry, couldn't resist. Anyway, 

[Ghoste]

So as it turns out, the vent was fine.  As mentioned the old seal looked to be almost new, which it was.  It did, however, come out very easily.  Extremely easily by my experience.  I don't recall it going in that easily but I also don't recall ever having new ones being more difficult to install than taking out the old one, which is exactly what happened tonight.  So, however the old one shrunk??, that must be where the leak was and to be honest , it did look somewhat like seepage around the shell, not throught the seal itself.  Who knows?  It took a couple of years to start leaking so if this takes a couple more years, then all is well.

[chargerbr549]

I just helped a friend of mine with his 69 R/T Charger and we put in National Brand seals only since most of the seals that you find now adays are pretty cheesey to say the least, there might some other good brands out there but you can't go wrong with Nationals. If you compare a CR brand which alot of seals brands look like them the metal thickness is thinner they usually don't have any type of sealant on the mating surface of the O.D. of the seal and the rubber lip us usually a very light duty single or a poor excuse double lip type seal. You probably shouldn't have to do it but I put a little bit of silicone around the outside outer edge of the seal where it meets the housing just to make me feel better that the fluild isn't leaking past that area. Just my way of attacking the problem.

Kevin