Front Pinion Seal Replaced and still leaks

[sswong98]

Hello All,

On my 1994 80 series, the front pinion seal had a small leak. I finally changed out the seal, however, the leak continues more so. A couple of things happened. I didn't jack up the L/C to change the seal. The FSM said the torque on the pinion nut was 145 Ft lbs. When I was torquing down on the nut, there was a snap. However,he nut was spot on at the strike point. Could I have damaged something to cause more of a leak?

The second thing, I am now thinking is the most likely issue is I didn't seat the new seal evenly. Meaning one part in further in compared to the other side. I don't know what I was thinking at the time. I should have tapped in the seal until it was even on all sides. Could this be the cause?

 

[Sarmajor]

The seal should be seated evenly and below the surface of the recess that it seats into. There should be a lip inside the housing to stop you seating it to deep.
What condition was the pinion flange surface where the seal runs? If it is damaged then it will just tear up the new seal.
Did you lube the new seal when you assembled it?

Not sure what could have caused a snapping sound during assembly. Seeing as you did not replace the crush tube it should have been a simple tighten to the same position as original and a bit of a nip up to ensure it was man tight before restaking the locking portion of the nut.

 

[sswong98]

Hello Sarmajor,
Thanks for your reply. I followed the diy from this post, and did grease the seal before installing the flange. I think the leak is due the seal not seated properly. I noticed leakage occurs while my L/C is parked. I only drove about 5-6 miles to for a test drive, so I am thinking I should be able to disassemble and re-seat the seal. The flange looks fine. Based on other posts, I lightly sanded the flange surface. I only have 170K miles on my L/C.

As I am thinking about the snap. I wonder if it is the torque wrench itself. When I heard the snap, I also felt a click.

Thanks for your help. I will disassemble this coming weekend and keep you all posted.

 

[Sarmajor]

I don't understand the sanding of the flange. Not sure why or where you would sand the flange. The surface the seal runs on is machined and polished.

 

[maxamillion2345]

Emory cloth around the pinion shaft sealing surface, totally normal and recommended.

 

[maxamillion2345]

I'd pull the seal back out but you may not be able to get it out without damaging it.

Either way. I'd check again to be sure that pinion sealing surface looks good. Then check to be sure you don't pinch the lip of the seal. Then be sure you get it seated squarely. You can probably seat the seal in a slightly different spot if the pinion is worn where the seal lip has be riding, aka grooved. Lube the seal up with oil as well.

As far as the snap, I'd expect it was your torque wrench. Crush sleeves are actually pretty hard to crush when you're intentionally trying, so you can pretty well expect it wasn't that.

 

[Cruiserdrew]

Many times when the seal leaks, it's because the bearing that supports the pinion is worn out. So replacing the seal doesn't do much. It may just be time to have your differential rebuilt with new bearings.

You always lube the seal with grease or gear oil prior to re-assembly.

The crush sleeve is an issue which is why the manual recommends not tightening to achieve the same preload on the bearing as before you took it apart. I am worried you may have crushed the crush sleeve even more and could potentially change the preload on the bearings substantially. The bearing then will lead a short and unhappy life.

 

[maxamillion2345]

I'd be really surprised if he heard a snap while crushing a crush sleeve that's pretty hard to crush intentionally. I wailed on a crush sleeve with my 2135 ti max for a long time to get it to crush at all, a lot of times it takes a big breaker bar and a lot of torque, well beyond 150 ft lbs.

That's just my experience though. If the OP is concerned he can roll that pinion with an inch pounds torque wrench and will want to see around 10-20 inch pounds of rolling resistance with the wheels and tires off.

 

[Cruiserdrew]

I sort of agree. The crush sleeve is hard to crush, although once it gets started, it is much easier.

The noise heard sounds like a torque wrench talking but hard to know.

But absolutely, with just a seal replacement, you tighten down to achieve proper rolling preload NOT the 145 foot pounds of a new set up.

 

[Pin_Head]

As noted above the bearing may be bad. Did you check the outer bearing. If there is significant sideways play it won't seal. The other possibility is that you F'ed up the new seal installing it. It happens.

 

[maxamillion2345]

I sort of agree. The crush sleeve is hard to crush, although once it gets started, it is much easier.

The noise heard sounds like a torque wrench talking but hard to know.

But absolutely, with just a seal replacement, you tighten down to achieve proper rolling preload NOT the 145 foot pounds of a new set up.

You're definitely right on all that.

 

[sswong98]

Hello All,
Thanks for all the information from everyone and PM messages. This is why I love this forum. I agree the snapping sound was probably my cheap torque wrench as I am thinking about what occurred. I am hoping the leak is due to the seal not seating properly and not the bearing. My rig only has 170,000 miles and no serious off-roading. I will take everything apart this weekend to re-seat the seal and properly tighten the pinion nut. I will keep you all posted.

 

[landtoy80]

When I rebuilt my front diff at 220,000 (it didn't need it but did it as I had it apart and had a kit) and the pinion seal leaked. Pun in another new seal and it leaked. Replaced the flange and it has been leak free for 215,000 mi. After removing the pinion nut a couple times after rebuilding I think I messed up the preload or something as there was a little more free play than after rebuilding it and it makes a little noise when you turn the pinion back and forth. I guess it didn't cause mechanical damage as its still fine after 215,000 mi.

Now that the seal is starting to leak again, should or can I just replace the crush sleeve or do I have to pull the diff and check gear lash?
I might just pull the diff as the diff gasket is seeping.

 

[maxamillion2345]

If you remove the pinion you'll need to set up the diff again.

Dude no offense but I'd have someone else do it.

 

[landtoy80]

I would do it again if I had the tools. Friend, when I lived in another state, had the dial indicators and I did most all the work while he guided me through it. Was not that hard to replace the bearings in the diff. Had I had a new flange, it would of been better. It was about 12 years ago when I did it. Was not sure if I could just replace the crush sleeve without resetting up the gear lash. I have a new rear flange with the rear diff rebuild kit, if I ever need to rebuild it.

 

[sswong98]

Hi All,

Here is an update... I tore everything apart. After a close examination, the new pinion seal was way off center. I thought only one section was off, but it turns about about half of the seal was off center. I used a brass punch and 2.5" pvc coupler to center the seal. I also tighten the 30 mm nut per some of your instructions. Tighten until I hit a wall, go little past the strike point. I took a 3 mile test drive and not leaks

Thanks for all the guidance. I really appreciate the help