Anyone use stop leak for pinion seal ?

David Neibert

SCCoA Admin
Found a small leak on my differential pinion and don't really have time to change seal before Power Tour. Options are do nothing and hope it holds up for about 1300 miles, or drain some of the gear lube and add some stop leak. Just wondering if anyone here has ever tried stop leak in the diff and if it worked.

David
 
Good afternoon


I don't know if this will help but a search of JEEP, Land Rover and or Bob is the Oil Guy forums will have additive results for pinion seal stop leak. It appears from my brief search it depends on the size of the leak.


Good Luck.
 
AT 205 works miracles for seals. I've used it in crankcase, floor jack, clutch cylinders, and on wiper blades. If the seal isn't shredded, it will work. Summit racing is cheapest
 
I'd be sure it wasn't overfilled...especially if the 3rd member/pinion angle is tilted away from normal.
 
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I'd be sure it wasn't overfilled...especially if the 3rd member/pinion angle is tilted away from normal.

Don't think it's overfilled or has an odd pinion angle. New cover and diff mount was installed several years ago and I haven't noticed any signs of leaks until recently. Changed driveshaft last year and it was fine.

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Denny's driveshaft and diff.jpg

David
 
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How old is the diff seal? If you replaced it, it should be reliable, I'd think, as long as the flange wasn't scored.

I'd remove the fill plug and leave it out for a while, just to be sure the level was correct - I don't think it takes much over to make the seal weep, but if it's been fine for that long, that's a long shot I guess. Adding some stop leak will let you re-adjust the level in any case, so...

Is it spotting the ground? Any chance the exhaust is helping the case and fluid to over expand and make it weep? Is the vent clear?

Keep a spare seal w/you during the tour, watch for spotting when parked and good luck.

Ken
 
How old is the diff seal? If you replaced it, it should be reliable, I'd think, as long as the flange wasn't scored.

I'd remove the fill plug and leave it out for a while, just to be sure the level was correct - I don't think it takes much over to make the seal weep, but if it's been fine for that long, that's a long shot I guess. Adding some stop leak will let you re-adjust the level in any case, so...

Is it spotting the ground? Any chance the exhaust is helping the case and fluid to over expand and make it weep? Is the vent clear?

Keep a spare seal w/you during the tour, watch for spotting when parked and good luck.

Ken

Diff seals and bearings were all replaced when 3.73 gears were installed back around 2000. Fluid has been changed a couple times since then and it's currently got Royal Purple 75-90 full syn that was installed with new LPW diff cover a couple years ago. I looked under the car this morning and there is one small spot on the garage floor about the size of a quarter, but I think that spot was from drips after returning from a dyno tuning session at SCU. Car has been driven a couple times since then and I doubt it was parked in the identical spot all three times, so leak may not be happening except when going very high speeds.

Planning to jack it up this weekend and pull the fill plug and check the fluid level and see if it looks like oil came from breather. After seeing how little has leaked on the floor, I'm feeling a lot better about driving it on Power Tour. I'll post my findings later.

Thanks, David
 
Got under my 91 SC this morning to see if I could determine where the rear end was leaking and how low the fluid was. Looks like it was leaking from the pinion seal but isn't now. The oil spot in front of the flashlight was the only oil spot on the garage floor, and it didn't look fresh. When I went to remove the fill plug (1/4"Allen), I found that it was over tightened and stripped out. I think the kid at Valvoline oil change place turned it the wrong direction. Because he couldn't get it out last week when I was getting the oil changed.

After trying several things to remove plug and failing, I tried removing the bearing pre-load stud on one side, to check fluid from there but they can't be removed from the outside. Looks like I'm going to have to remove the rear cover to get the plug out. Before doing that I'll just pull the entire pumpkin and rebuild it. Not really wanting to do that until winter, so crossing my fingers that it has stopped leaking.
I cleaned everything off and took it for drive and will check it tomorrow for any signs of leaks.




leak 0.jpg

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leak 4.jpg

leak 5.jpg


David
 
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Drove the car a couple more times and even got it up to about 90 mph and then parked it in the garage all day with clean cardboard underneath. No runs, no leaks or drips. So I guess it will be okay for Power Tour.

Oh yeah, car drives so much smoother at high speeds. Not sure if it's the new driveshaft, the new shocks or something else, but it feels great now.

David
 
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