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Discussion Starter · #1 ·
Just replaced the pinion seal on my impala and did a diff fluid change and the seal is still leaking. I've been reading on ther forums that if you overfill the diff fluid will leak out of the pinion seal. Is this true or should I redo the seal?
 

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The seal installation can be picky, in theory if you overfill it could leak out, but really it shouldn't and I doubt that you overfilled it, when I install a seal I always pack the groov of the rubber portion of the seal with red and tacky grease, never had a leak with the ones that I installed.
 

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Discussion Starter · #3 ·
So should I drive it for awhile to c if it stops or redo the seal? And what's the fluid capacity I just filled to the fill hole
 

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That is all that I ever go by for the fluid capacity is to the bottom of the fill hole. You can try it and see what happens, is it possible you got sold the wrong seal? I was thinking that Autozone or where ever was selling the wrong diameter seals as they listed for our cars, I could be wrong though, also where is it leaking from, the outer portion of the seal of where the inner rubber is? if it is the outer portion you could have a score in the seal bore of the housing causing a leak, if you replace you could also put a very thin bead of Ultra Copper silicon on it and try that.
 

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Discussion Starter · #5 ·
Ok I'll have to check it out. The parts store had two seals so I bought both and only one fit around the yoke the other was too small so I took it back.
 

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So should I drive it for awhile to c if it stops or redo the seal? And what's the fluid capacity I just filled to the fill hole
Doubtful that it will fix itself, so plan for a re-do. You SHOULD use a new crush sleeve and lock nut, and make sure the pre-load is correct on the pinion bearings. You should have measured the torque required to turn the pinion (ie. drag) before disassembly so you could put it back to the exact same value at re-assembly.

The axle housing capacity is about 70 ounces - 3 bottles of GM gear lube (23 oz each) plus additive/friction modifier puts you right there.

A couple of threads/posts that you may find useful:

http://www.impalassforum.com/vBulletin/showthread.php?t=242102

http://www.impalassforum.com/vBulletin/showpost.php?p=2334567&postcount=8
 

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I hate #[email protected])ing pinion seals

Just replaced the pinion seal on my impala and did a diff fluid change and the seal is still leaking. I've been reading on ther forums that if you overfill the diff fluid will leak out of the pinion seal. Is this true or should I redo the seal?
I did one better, just finished changing mine and went from a small cosmetic leak to leaking like a stuck hog. I've completely redone my suspension, water pump, opti, timing cover seals, etc and this has been the first real gotcha for me. Here is where I stand... I didnt measure the torque prior to removing the bolt (I don't have an inch-lb. torque wrench and could not find one local or for less than a hundred online), but I did mark it and count the threads (4 like everyone else I've read) and replaced it exactly to the original mark. I ways also sketchy about the RTV sealant I didn't "pack" it, I think I just put a small thin layer, Haynes confused the hell out of me when it came to this for some reason, I put the RTV on the splines on the shaft in the center of the seal, correct? Should I glob it on there so that it completely seals the area between the rubber of the seal and the shaft itself? What about the crush sleave and locking nut? I've heard this may need to be swapped out if the locking nut is over tightened, or not having that original torque measurement? Don't know where I went wrong and really don't know where to go from here, any advice would be appreciated. Started off a small leak but I drove it a few miles and now it's slinging grease. Damn near ready to pay someone to fix this but I'd probably spend more effort trying to find a good mechanic (the guy I used retired about a year ago) than redoing it all again.
 

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You probably got the torque close with the method that you used, but the optimum method is what Bill posted above. I am not sure that I understand why the manual that you have stated to pack it with RTV. When I did mine it was leaking even after a good mechnic put a new seal in, I removed that one and noticed there was slight scoring on the inside of the rearend where the outer edge of the seal sits. So I put a layer of RTV around the outside edge of the seal before I put it in. And I always put red and tacky grease in the v groove part of the seal to keep it from getting destroyed until gear lube can get up there to lubricate it after the change, plus it provides a layer of protection in there. I learned this from my dad, who was a mechanic for 35 years. It always worked for him and I never had a leak from seals that I have replaced using this method.

Where is it leaking from? I never put RTV on the splines either. And from what your post says you put RTV in the v groove portion of the seal? That could of destroyed the sealing nature of the seal, as it will harden up a bit and distort it.

It is possible that the crush seal got screwed up, even though you marked it, when retightening it down, causing the pinion to move in and out making it leak.

Not taking anything away from your abilities but you may want to take it somewhere and have them change it, if it leaks again then you have a warranty with the procedure done and just take it back :) Sorry probably not much of a help.
 

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Discussion Starter · #10 ·
I got a major problem. Did the reseal with rtv and grease no leaks BUT..... when I was removing the old seal ( instead of buying a seal puller which I did after) I tried to use a pair of long nosed needle nose needless to say I broke the tip of the needle nose pliers off in the seal and I thought it came out but when I put everything back together the car had a nasty vibration and my buddy thought the driveshaft was bent. But the pinion yoke was cocked a little making the angle out of wack. When I took it apart again I pulled out the pinon yoke and there was the end of my needle nose stuck on the back of the pinion yoke. I didn't see a y scoring of any kind and I only drove it about 20 miles or so .I got everything back together again and still have a slight vibration not nearly as bad but noticable ( to me at least). So did I ruin a u joint? Pinion bearing? Rear end? WTF is up any ideas?
 

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You probably got the torque close with the method that you used, but the optimum method is what Bill posted above. I am not sure that I understand why the manual that you have stated to pack it with RTV. When I did mine it was leaking even after a good mechnic put a new seal in, I removed that one and noticed there was slight scoring on the inside of the rearend where the outer edge of the seal sits. So I put a layer of RTV around the outside edge of the seal before I put it in. And I always put red and tacky grease in the v groove part of the seal to keep it from getting destroyed until gear lube can get up there to lubricate it after the change, plus it provides a layer of protection in there. I learned this from my dad, who was a mechanic for 35 years. It always worked for him and I never had a leak from seals that I have replaced using this method.

Where is it leaking from? I never put RTV on the splines either. And from what your post says you put RTV in the v groove portion of the seal? That could of destroyed the sealing nature of the seal, as it will harden up a bit and distort it.

It is possible that the crush seal got screwed up, even though you marked it, when retightening it down, causing the pinion to move in and out making it leak.

Not taking anything away from your abilities but you may want to take it somewhere and have them change it, if it leaks again then you have a warranty with the procedure done and just take it back :) Sorry probably not much of a help.
It's leaking from the flange lip that cuffs around the housing.
How much would I be looking for something like this? I don't understand the crush sleeve/preload thing and really dont have any idea how to check it. If the crush sleeve is screwed up am I looking at pulling everything apart, gears, posi, etc? If I had it all apart I'm sure it would all make sense and as much time as I've spent dicking with this thing I think I could have pulled it all apart and put it back together by now. I keep reading everyone mention grooved this or that caused from wear, I didn't see any grooves or scoring on anything. Plus I just saw another thread about different seals, the seal I originally bought was wrong, took it back and matched a seal with the original one that came out, fit like every other seal I've ever replaced, but could it still be wrong? The seal I bought was for listed for a 96 Caprice with G80 rear-end.

Right now though with my understanding of the crush sleeve I could go in and they could tell me it's screwed up and the entire rear end needs to be rebuilt that'll be $2000. I mean I have no idea what something like this would cost and there isn't a mechanic I really trust anymore. I'm so frustrated with this I want to go rip one apart so I will understand it.

If I do pay someone to do this hopefully I can find a shop that doesnt mind me standing there and having them explain this **** while they do it.
 

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Well if it is leaking from the lip then that would tell me there was a score or something in the housing, I ALWAYS RTV the outerlip, to counter act anything like this. As far as crush sleeve you are probably close, the correct way to measure rotating torque before and after is with the axles out but you can do it with the axles in it would just be a higher number. You probably got it right as it isn't blowing fluid out of the seal portion. Also note when putting in the seal I have found that it has to be perfectly parallel with the bore in the housing or it can oblong the seal itself going in and it can cause a leak without a score in the housing.

Also if the crush sleeve was really screwed up you would know, the rearend would whine or start to after a bit as the pinion bearing start to fail, you should be fine though. The crush sleeve provides a preload on the pinion bearing so they don't "free" float in there races, causing heat and taking out the bearing. The seal that you got is probably right, take it out and try again is all I can offer :)
 

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I just went with a new pinion flange that had the tripple lip seal on it, (GM OEM part), and never had to worry about leaks :)
 

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I got a major problem. Did the reseal with rtv and grease no leaks BUT..... when I was removing the old seal ( instead of buying a seal puller which I did after) I tried to use a pair of long nosed needle nose needless to say I broke the tip of the needle nose pliers off in the seal and I thought it came out but when I put everything back together the car had a nasty vibration and my buddy thought the driveshaft was bent. But the pinion yoke was cocked a little making the angle out of wack. When I took it apart again I pulled out the pinon yoke and there was the end of my needle nose stuck on the back of the pinion yoke. I didn't see a y scoring of any kind and I only drove it about 20 miles or so .I got everything back together again and still have a slight vibration not nearly as bad but noticable ( to me at least). So did I ruin a u joint? Pinion bearing? Rear end? WTF is up any ideas?
Well any number of things could of happened, doubt you took out a u joint for 20 miles of use, you could of bent the pinion itself whenyou torqued everything back down, taken out one of the pinion bearings etc. you can take the driveshaft back off, rotate the pinion and see if it wobbles.
 

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Buffman & 94MI9C1, thanks for your input, I really value your opinions and experience.

The car is smooth as silk, no scrapping or whining noises (Other than whats coming from the driver seat ;) ).

Thinking of making another go at this. So sum this up real quick, RTV on the outer lip of the seal where it means the housing to seal any scoring, I had put it on the splines of the flange because the Haynes manual had said something to that affect I think (I was having a hard time understanding the Haynes book but my understanding is so that it would not leak from splines and that the new Yoke kit addresses this). Red and tacky grease on the V-groove (the portion of rubber that meets the shaft?), I have always done this on all seals I've replaced. Should I purchase the inch-pound torque wrench now or just stay with my current method now that the original measurement is lost? What about my fluid? Is it possible to salvage all the new fluid I put in there?

Buffman, if I went with the new yoke what does that do to the preload? I mean could I just take off the current yoke and replace it with the new one, counting the threads, making and tightening to the mark again? Now that I've lost the original preload measurement it doesnt seem viable.
 

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The new pinion seals from GM have a hard rubber like bead around the outer metal of the seal which makes them a little harder to pound in, but they don't leak. The seals from Autozone don't have this rubber bead.
 

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The new pinion seals from GM have a hard rubber like bead around the outer metal of the seal which makes them a little harder to pound in, but they don't leak. The seals from Autozone don't have this rubber bead.
Using the same part #? Is RMS Auto carrying the new style?
 

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yes I do believe they have it. Buffman can comment on the part number as I am not sure on that one
Bill H should have the #, I don't think I do anymore. I originally sourced mine from SDPC for like $80.00
 

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For all the answers.... search term "pinion seal"

To clarify, if it's not getting through:

The pre-load, if properly set, results from the crush of the sleeve during initial installation. This is meant to keep a specific range of tension on the pinion bearings--ie. to control the "float" of the pinion shaft so that the gear mesh is maintained in an acceptable manner.

BEFORE the pinion flange nut is touched, the force required to turn the pinion (specific procedure is in the FSM) should be measured with an pound-inch torque wrench (not a clicker, but a dial or pointer style).

When the seal is serviced, and while the flange is removed, a new crush sleeve can be installed (you can try with the existing sleeve in place--just realize it could fail to make pre-load properly) with the objective that once everything has been re-assembled, you want to re-tighten the flange nut to the point that you're able to repeat the turning force (torque) that was measured before disassembly.

Counting the turns of the nut is simply going to put you "in the ball park"--what you don't want to do is over-tighten the nut. And, by the way, be sure you DO use a new locking nut each time you pull the flange. The service kit includes a new lock nut, but I do not recall whether it includes a new crush sleeve.
 
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