# 1991 Caprice 5.0l Pinion Seal



## WyrTwister (Jul 22, 2013)

Need to replace the leaky pinion seal .

Advice ?

Anyone know the torque spec on the pinion nut ?

Hope my electric impact wrench has enough power to remove the nut . I am thinking the nut will be metric ?

Wondering how difficult it will be to remove the yoke ? I have a pulley puller & P B Blaster . Do not know if the " legs " of the puller will grip the yoke ?

God bless
Wyr


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## Windows on Wash (Aug 30, 2011)

Have a couple of pieces of wood down there as well. 

You don't want to put too much forward pressure on that pinion and torque the ring gear and shims at all. 

Most times the yolks will come off without too much trouble. Soak it pretty well and then have your seal puller ready.


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## WyrTwister (Jul 22, 2013)

I appreciate your advice , but most went right over my head ?

What are the pieces of wood for ?

I plan to jack the car up from the frame , on the passenger side , ahead of the axle / wheel . Bricks for chocks front & back of the other 3 wheels / tires . Jack stand supplementing the jack .

So I am puzzled concerning pressure on the ring gear & pinion ?

I have a pulley puller , but no seal puller . Figured I would remove the seal with an awl & screwdriver ?

Can you attach a photo of a seal puller ?

Thinking of using a mallet & large socket to drive the seal back into place , into the differential . Or , maybe a pipe coupling .

Thanks , 
Wyr
God bless


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## Windows on Wash (Aug 30, 2011)

Jack the car up on the frame, support it, let the suspension drooped down to give you better access to the differential, disconnect the driveshaft from the rear, pull the driveshaft to the side but don't pull it out of the transmission otherwise you'll lose a bunch of fluid there.

Soak the bolt and pinion with PB blaster. Put your electric impact on it and you may need to use a screwdriver to keep the pinion from turning.

The wood blocking was to hold the pinion steady and break the nut loose. 

Good vid. Bunch of commonalities. 

https://m.youtube.com/watch?v=f-H0KQG5uOI

Don't mind the language...he's Canadian. 😜


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## WyrTwister (Jul 22, 2013)

That is pretty much what I had planed , as far as jacking up & supporting the car .

If I need to hold the yoke , I can use a big pair of Channel Locks , if I can find them .

Will look at the video & maybe I can figure out the blocks of wood .

Just had a thought . If I let the car / tire down , gently , on a block of wood , I think that would also help hold the yoke and the whole axle assembly still , while removing the nut ?

God bless
Wyr


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## nap (Dec 4, 2007)

The impact should take off the pinion nut without a problem. Yokes aren't usually that difficult to remove. You've had suggestions for that so I won't bother.

As is explained in this link;

http://www.chevytalk.org/fusionbb/showtopic.php?tid/276281/

You do not torque the nut when replacing it if you aren't replacing the crush sleeve. 

A seal remover is a tool with a little hook on the end and a place to tap the tool pulling the seal out. Unless you think you might use it more I would just use your method.


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## WyrTwister (Jul 22, 2013)

No , I do not intend to replace the crush sleeve . All I am trying to do is replace the leaky seal .

But I got a couple of ideas , reading the above thread .

Thinking about taking a small center punch and making witness marks on the yoke , pinion nut & end of the pinion ( far enough inward on the " face " of the pinion so that threads are not damaged . ) 

And maybe using low strength LockTite on the pinion nut .

Another you tube video 

https://www.youtube.com/watch?v=15zHpz6Zx8c&app=desktop

and

https://www.youtube.com/watch?v=HNkGdByzyjI

God bless
Wyr


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## raylo32 (Nov 25, 2006)

I did one of these recently on my 1994 Camaro. The yoke came right off, no need for a puller. The idea is to use paint or punch to mark the yoke nut then count the turns. Reinstall to the same count. Other folks count the exposed threads and put it back the same way. No way to use a seal puller to remove the old. I did it the old fashioned way with hammer and screwdriver to deform then grab it with pliers.


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## WyrTwister (Jul 22, 2013)

Was there any need to polish the sealing surface on the yoke , to remove rust or pitting ? With , maybe , 1000 grit sand paper ?

Thanks ,
Wyr
God bless


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## raylo32 (Nov 25, 2006)

No. The seal has a metal surround that is a tight press fit into the diff housing. The actual seal is a rubber skirt that rides on the shaft. Can't see how that shaft could ever corrode enough to not seal.

Are you sure it's the pinion seal that is leaking? After removing the old seal and finding it intact I now believe that my pinion seal leak might just have been some grease that was flung from the u-joint over 113,000 miles.



WyrTwister said:


> Was there any need to polish the sealing surface on the yoke , to remove rust or pitting ? With , maybe , 1000 grit sand paper ?
> 
> Thanks ,
> Wyr
> God bless


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## WyrTwister (Jul 22, 2013)

No , it is dripping on the drive . :-(

I put some more gear lube in the diff , last weekend & it is continuing to leak .

This car set dor about 15 years & I figure the seal just dried out and got hard ?

God bless
Wyr


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## raylo32 (Nov 25, 2006)

Maybe. My old one was original since 1994 and it looked OK when I got it out. Car is driven infrequently for the last 10 or 12 years. Yours might be torn... One other possibility is the diff is overfilled. The seal won't work if the liquid level is against it. But I assume you have checked that.



WyrTwister said:


> No , it is dripping on the drive . :-(
> 
> I put some more gear lube in the diff , last weekend & it is continuing to leak .
> 
> ...


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## WyrTwister (Jul 22, 2013)

I am pretty sure the Diff had not been filled since it left the factory . Last oil change , I asked them to check the oil level , since I knew the pinion seal had been leaking .

They said the plug was rusted & they could not get it out . Last weekend I jacked it up , sprayed the plug with PB Blaster & let it set a little while . Then used a big 1/2" drive ratchet & extension + 1/2" x 3/8" reducer to remove the plug .

Squirted in a bunch of oil & stuck the plug back in . Could not tell how full I had gotten the diff , as I had the car jacked up from the passenger side & that tilted the diff , making the " hole " high .

I figured the bottom of the seal ran in oil ? If not , how does it receive oil ? Is it slung up there ?

Just got back from buying some break clean to wash down the outside of the diff . And some blue LockTite to put on the pinion nut & the bolts holding the U-Joint to the yoke .

Thanks ,
Wyr
God bless


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## nap (Dec 4, 2007)

You can use a seal puller if you use this type but as I said, unless you will use it more than this once, just use the screwdriver method:










I would gladly loan you mine if you were close. 

a seal, even when worn, does not necessarily look bad. Your thoughts that it may simply be hardened is a legitimate possibility.

when you have the yoke off, look at it. There is possibly corrosion near where the seal rides that may cause an issue with the new seal, especially if the seal does not drive in at least as far as the current seal. What I use to clean up the sealing surface of the yoke is a 1" by as long as I want strip (it comes in really long rolls) of (this is what it says on the strip backing) A/O RES CLOTH T2 J CLOSED

I believe it is 180 grit emery cloth but not certain., I lost the box long ago and now only have the remaining roll of sanding cloth. You do not want to remove any more material than necessary to clean the wear area. You are reducing the diameter so you do not want to make it too small so the seal cannot seal.


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## WyrTwister (Jul 22, 2013)

Thank you for the offer to loan the seal puller . 

But you appear to be over 1,000 miles away . :-(

I will probably use a screwdriver and pliers .

I am familiar with emery cloth , although about the only time I use it is when I am doing DIY plumbing . To polish copper pipe & fittings , before I solder .

I was wondering about sanding the surface the seal runs against , to remove corrosion , pitting or dirt . The car spent so many years sitting , rust / corrosion is a real possibility .

I bought 80W-90 gear oil . The guy at the parts store asked if I wanted synthetic . I told him conventional oil . Did not know if synthetic was comparable with conventional . And do not plan on draining out all the existing oil .

Thanks , 
Wyr
God bless


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## cjm94 (Sep 25, 2011)

The proper 'torque' is a rotating torque around 28 inch pounds on most cars. Most people who do it all the time go by feel. A paint mark on the nut and yoke and feel how the yoke turns by hand prior to loosening and you should be fine. Just don't over tighten we see many come back with bearing failure from the young guys starting out that overtighten them.


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## WyrTwister (Jul 22, 2013)

I plan to put witness marks on the pinion , pinion nut and yoke . And count exposed threads , above the pinion nut .

With the intent of putting it back the same as it was , before I removed the nut .

God bless
Wyr


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## Brainbucket (Mar 30, 2015)

15ft lbs turning torque, it takes 15ft lbs before it turns, rotates. If new bearings are installed 25ft lbs of turning torque. Can't measure that with a clicking torque wrench. Has to be the 'needle type'. Now that's with the carrier out. I just feel it before I remove it. Feel how much force I have to make before it turns. Is it moving up and down? (Bad bearings) Look how many theads are exposed after the end of the nut. How much 'play' does it have. Turning it untill it is making contack with the ring gear. Should be very little. Say .010" Just make it like it was before you took it part.:thumbsup:


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## Fix'n it (Mar 12, 2012)

Brainbucket said:


> 15ft lbs turning torque, it takes 15ft lbs before it turns, rotates. If new bearings are installed 25ft lbs of turning torque. Can't measure that with a clicking torque wrench. Has to be the 'needle type'. Now that's with the carrier out. I just feel it before I remove it. Feel how much force I have to make before it turns. Is it moving up and down? (Bad bearings) Look how many theads are exposed after the end of the nut. How much 'play' does it have. Turning it untill it is making contack with the ring gear. Should be very little. Say .010" Just make it like it was before you took it part.:thumbsup:


umm. thats INCH #'s. NOT foot #'s.


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## Fix'n it (Mar 12, 2012)

WyrTwister said:


> I plan to put witness marks on the pinion , pinion nut and yoke . And count exposed threads , above the pinion nut .
> 
> With the intent of putting it back the same as it was , before I removed the nut .
> 
> ...


this is the way to do it. but, you don't need to count threads. because, as you are tightening the nut,it will turn somewhat easily UNTIL it gets to about 1/4 turn from where it needs to be. 

and "staking" the nut is not a bad idea.


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## WyrTwister (Jul 22, 2013)

I plan on using low or medium strength LockTite on the oinion nut . Think blue is what I bought .

Have not made any progress on the Caprice . Intended to work on this , last weekend . However , ended up working on 2 lawn mowers and then mow the front & most of the back yard . :-(

Hopefully I will get back to the Caprice this coming week end .


God bless
Wyr


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## Brainbucket (Mar 30, 2015)

Fix'n it said:


> umm. thats INCH #'s. NOT foot #'s.


 That's what I meant. But somewhere between my brain and my fingers got jumbled up. Thanks for the correct #s.:laughing:


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## WyrTwister (Jul 22, 2013)

May end up having to crawl under the house and work on my cold water lines / plumbing , this weekend . :-(

I dislike that more than working on cars .

Would rather work on naps . 

Thanks all , 
Wyr
God bless


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## nap (Dec 4, 2007)

On my what?


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## WyrTwister (Jul 22, 2013)

Plumbing . Cold water lines / pipes .

God bless
Wyr


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## Fix'n it (Mar 12, 2012)

Brainbucket said:


> That's what I meant. But somewhere between my brain and my fingers got jumbled up. Thanks for the correct #s.:laughing:


yes, i know you know. but i corrected just in case you didn't come back.
and i also have the brain finger thing :laughing: :huh: 



nap said:


> On my what?


:laughing::laughing:


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## WyrTwister (Jul 22, 2013)

Follow up - Just finished with the pinion seal on the Caprice & got out of the shower . I was a dirty puppy .

I was running out of daylight . :-(

Put most of a " bottle " of 80w-90 oil in the diff , until it started running out of the fill hole . Replaced the plug and tightened it up .

Had my Wife drive the Caprice slowly around the block . While she was doing that , I spread cat litter on all the oil spots on the drive .

Will have to wait to see if it leaks or not .

The seal surface of the yoke has 2 " wear rings " . I used 500 grit sand paper on it , then switched to 1000 grit . I could still lightly see the 2 " wear rings " , but could not feel them when I drug my finger nail across them .

Lubed everything as I reassembled the parts in reverse order .

This last weekend was not good . Worked on plumbing / cold water lines under the house . 3 steps forward & 2 steps back . Ended up creating a leak , where it was not leaking . Praise the Lord ! . It was no longer leaking by the time I crawled out from under the house Sunday PM .

God bless
Wyr


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## Fix'n it (Mar 12, 2012)

the grooves are normal and yours sound inconsequential .

how did you tighten the nut ?


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## WyrTwister (Jul 22, 2013)

Counted threads , used witness marks . 

Tightened the nut with a 1/2" drive ratchet .

Blue LockTite on the pinion threads .

Question . There was a hard white substance on the pinion threads , pinion nut and splines of the yoke . I am guessing it was some kind of dried out white grease or some kind of " sealant " ?

I scraped it off the splines of the yoke . I left the pinion splines & threads alone . did not want flakes of that stuff getting inside the diff .

God bless
Wyr


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## WyrTwister (Jul 22, 2013)

I removed the old seal with a screwdriver & ball peen hammer . And a pair of dikes .

I used a large 3/4" drive socket & the ball peen hammer to drive the new seal into place . After I lubed the rubber surface and the outside metal perimeter of the seal ( to make it slide into the recess in the diff , more easily ) .

Lubed the surface of the yoke , that contacts the rubber of the seal .

God bless
Wyr


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## Fix'n it (Mar 12, 2012)

sealant. most don't have any. i put a little high temp silicone. 

should have put a lil silicone on the outside of the seal . but there already is some on the seal, so you are probably ok there to.


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