Front axle pinion help

[jhoag]

So when tearing down my front axle I made a rookie maneuver, I didn't take note of how many threads were showing on the pinion.  Now that I am trying to put it back together Im hitting a snag.  All I did with the pinion was replace the slinger, gasket, and seal.  Now that the new parts are on and I tried putting the yoke back on Im finding a problem.  Using my impact wrench, I am trying to torque the shaft nut down but am finding that I have no threads showing, yet the dust shield is hitting the new seal causing the yoke to bind up.  My guess is that either the pinion shaft as been pushed into the differential housing (it doesn't look like it has from the inside), or the new seal is not seated all the way (it sits flush with the outer lip of the differential housing).  Has anyone had a snag like this or does anyone have an idea for me to check or try.  I am going to pull the yoke off again today and recheck everything.

[Bob W]

Sounds like the new seal is different or not installed deep enough.

[jhoag]

Thank you, thats what Im hoping.  I looked at the Vernco website and it looks like it should sit below the lip of the housing.  Im gonna try that as soon as I can get the yoke off.

[Doug]

I have run into that problem before several times with my jeep. �It seems that there are three components which all need to match up. �The yoke seal, the dust shield and the pinion yoke. �The original ones were all designed to work together and fit properly. �Change one to a modern, reproduction or replacement model, and it may conflict with the others. � I found after replacing a seal once that I had the dust shield yoke collar was eating into a seal. �Also, �one time I got a seal and it was not clear which was it was supposed to be installed and I actually had it installed backward and it was hitting the dust shield. �

Did you happen to keep you original parts to compare? �That would be helpful to see where you were off. �

Also to complicate it, some of the later yokes eliminated the dust shield and I am not sure if you can just slide your old dust shield on a replacement yoke if it was not designed to make room for the dust shield.  I recall one time sending back a replacement yoke and going and finding a NOS yoke with integral dust shield.

[Doug]

BTW, one additional thing to consider.  You mentioned the dust shield was hitting.  On my jeep I only have a large dust shield on the rear axle and on the forward output shaft of the transfer case.    My front axle does not have a large dust shield.   There may be a little tiny dust shield but not much of one if at all.   Are you by any chance trying to install a large rear dust shield on the front axle.  If so that may be your problem.  I do not think the yoke is designed to have one.  Also, if you do install the larger dust shield on the front axle, it would act as a scoop for picking up mud when the jeep was in forward motion and would pack sand into the seal which would obviously be counterproductive to seal life.    So, I guess what I am saying is that the yoke and dust shield setup is different for the front axle than it is for the back axle.  Check and make sure you have the right parts in the right place.

If you do have all the right hard parts, then more than likely the modern seal has a different shape or you could be installing it backwards.   Just a few ideas to consider.

[Doug]

See the seal in the photo to the top left of this webpage (It is installed with the concave or cupped face pointing out to allow the dust shield to fit around it). �Do you see how the seal is laying and it appears backward from any normal seal that you would install. (see the transfer case seal to the right which has a flat surface pointing outward) �Sometimes the problem is installing the seal backward. �

http://www.willys-jeep-parts.com/index.php?cPath=101&&page=2

[jhoag]

I think you were right Doug, I think I had the seal on backwards.  I originally installed it so the flat aspect was inside, which left the part with the step (where the spring is housed internally) on the outside.  Hence why the dust shield was hitting it.  Luckily I had a second seal here which was meant for the rear axle (sorry rear axle, you will have to wait for another shipment).  I installed it with the step inboard and the flat outboard and was able to torque it all up and everything seems well in my garage again.  BTW, my front dust shield is a small one in comparison to the large one on my rear axle.  Thank you for the help.

Jeremy

[Doug]

That was the same mistake that I made one time on my rear pinion. �Intuition tells you to put it with the flat part out so that you have a smooth flat surface to lay a piece of wood across to hammer it in. �Now that I think about it, when I figured it out and flipped it over, I had to fashion a seal driver out of a PVC coupling (1-1/2 inch if I recall) so that I could hammer it in without damaging the protruding center portion. � �As you said, one of the best indicators of which way to install a seal is to make sure that the exposed spring band is facing toward the pool of lubricant. � �Good job on getting it done. � �;)