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Rear axle pinion seal?

76k5blazerr

76k5blazerr

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So I refilled my gear oil in the rear axle yesterday, then noticed that now it's leaking pretty bad while driving. Fluid is coming out of where the driveshaft bolts to the diff. That would be the pinion seal that is bad right? Is it hard to replace and is it something you can get at orielys or something? Can you go in and just replace that seal or do you have to do other parts as well?
 
What rear axle do you have?

I would honestly want to put the rear on jackstands, remove the driveshaft, and see if there is play in the pinion. If there is play, that needs to be fixed first... that could be bad pinion bearings, or somehow the crush sleeve got crushed some more.

With the seal being behind the yoke, you'll need to set the pinion pre-load properly after seal replacement, if that's the way you go. When setting up my 12-bolt, we set the pinion preload with the carrier removed, using an inch-pound torque wrench.

Clay
 
I've got a 12 bolt as well. I know there is a little play in it but that's not really as much of a problem as the leak is it? I mean I figured a little play was normal on an almost 40 year old truck. But anyway if I were to go ahead and replace the bearing and crush sleeve as well as the seal would that be a real hard job? And can I get by with just replacing the seal to just stop the leak?
 
I think others have gotten away with just replacing the seal. When re-installing the yoke, you will be able to take the play out, but without removing the diff you won't get an accurate reading on the preload of the bearings.

If you replace the bearings, you'll need to pull the diff anyway. I got a bearing kit from Jeg's which was something like $60 or $80, which was actually an install kit, with new shims, crush sleeve, marking compound etc. Do you have a press?

Clay
 
Ok, Well since it won't be but half a year till I rebuild the axle anyway when I restore this truck I think I'm just going to go for replacing the seal and maybe taking the play out. What were you saying about getting the play out? I geuss my question is how should I go about replacing the seal and taking the play out without F ing anything up.
 
Alright, you'll probably be fine if you are re-building the axle in a year.

To replace the seal, you'll need to remove the yoke, and there is a splash guard of sorts behind it, before you get to the seal. The pinion shouldn't move too much, so you'll need to somehow pry that seal out of there; that will be the difficult part, without buggering up the seal surface on the pinion. Install the new seal, and install that splash guard or whatever it is. We used silicone to hold it in place, otherwise it spins & jingles. Then... install the yoke, and probably just torque that nut until the play is gone. There is a very minor amount of preload on the pinion bearings; if there is play in it now, your preload is gone. I forget the number... we used new bearings during my gear swap, and it was like 20 inch-pounds of twisting force. Not on the nut, but how much force it took to turn the pinion by itself.

(Now that I think about it, you may want to just take some time, pull the diff out keeping the bearings & shims in their proper location, and beat the pinion out to replace that seal. That would make the job a lot easier. Also, having someone to help with this part is key!)

Clay
 
I watched the video... OK so it's early for me after a long week of starting at 5:00am everyday :) The seal surface is on the yoke, so it is pretty easy to do without pulling the pinion out. But, taking the play out of the pinion bearings without going too tight will be the hard part. Make sure it spins somewhat freely, without play, after that nut is tight. Also, stake it in place once it's good, so it won't back off.

Clay
 
Truck 12 bolts have failure prone pinion bearings, if there's any play there they are bad and that's the cause of your leak. Changing the seal won't fix the leak.
 
Mark the nut to the pinion flange before taking it apart.

Replace the seal.

If the nut is still good you can reuse it, (locking feature)



Reinstall and tighten the nut to the mark you made earlier and tighten further 1/16-1/8 of a nut flat. ( just a bit)

Then if you have any play tighten another 1/16-1/8 at a time till play is gone.

As long as the bearings are not shot you'll be good till rebuild or longer.
 
38377k5 said:
Truck 12 bolts have failure prone pinion bearings, if there's any play there they are bad and that's the cause of your leak. Changing the seal won't fix the leak.
Click to expand...

this. Your leak will reappear in a day or two if not on the first drive. Any play in 12 bolt pinion bearings and it's replacement time
 
Who knows what size the pinion nut is? What size socket will I need for it? Need to make sure I have a big enough one before I do it.
 
So today when I tried to replace the pinion seal I took the bolt off but couldn't get the yoke off, it didn't want to pull off. Is this a common issue? How do I go about getting it off?
 
Yoke puller is what I use but before then a brass hammer. I have resorted to normal Hammers on occasion but you gotta be careful a normal hammer can ruin a yoke fast
 
Alright I'll look into a yoke puller, so basically once the nut is off there's nothing else holding it on and it just has to be carefully manhandled off of there?
 
Yes,just a tight splined fit--you might be able to use a steering wheel puller to pull it off by attaching it to two of the u-joint cap bolt holes in the yoke...

They usually aren't that difficult to get off..
I've done a few using a piece of a 2x4 and a hammer..
 
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