89 Chev 4 x 4 Rear Axle Seals

Oriley · 03-09-2009, 10:07 AM

Bought this truck 11-07 with 123,000 miles.....great shape except both rear axle seals were leaking. Brought it in for new shoes and seals.

Last September I drove about 250 miles, rest of the time it sits in the garage.

Drove it out of the garage a couple months ago to warm it up, everything fine.

Drove it out today and there is oil on the inside of the rear drivers tire (just one spot) and a small puddle on the floor.

How in the heck can a seal, with less than 300 miles on it, just decide to start leaking after 15 months? I don't get it. And why would both seals be bad when I bought it? Something else has to be going on here.

The only thing I can think of is pressure building up??? Is there some sort of breather/vent on the rear end that might be plugged? I haven't a clue right now, very odd to me.

Any suggestions for what I can look for?

The truck is very tight and runs great except for this problem.

Thanks

redneck 0991 · 03-09-2009, 11:01 AM

there is a breather tube on the rear diff. it is on top of the diff and it runs up and connects 2 the frame. it allows the pressure in the diff 2 equalize and prevents pressure build up. i dont think that it would cause ur seals 2 leak but it's worth a shot checking it.

stumpuller454 · 03-09-2009, 11:06 AM

Quote:

Originally Posted by redneck 0991

there is a breather tube on the rear diff. it is on top of the diff and it runs up and connects 2 the frame. it allows the pressure in the diff 2 equalize and prevents pressure build up. i dont think that it would cause ur seals 2 leak but it's worth a shot checking it.

yeah check the hose AND the fitting in the diff, sometimes the hose is okay but there is **** built up on the fitting, use a small pick to poke throuugh it to check. If you have it apart you may want to check the surface of the axle were the seal rides, it could be grooved or damadged. Might want to use a micrometer to see if its within spec.

bradrhale · 03-09-2009, 11:38 AM

if the truck has sat up for an extended period of time, seals can dry up and become brittle causing premature failure.
are you sure that this is a wheel seal and not a brake cylinder leak?? these are prone to leak as well.

Oriley · 03-09-2009, 11:39 AM

A hose/fitting on top of the pumpkin.....I'll check that out.

I don't have it apart yet, we have a couple days of below zero coming so I'll wait a bit.

Just heard from my nephew that IF the axle is bad I can put a 'speedy sleeve' on it, whatever that is. Hard to believe the axle would be worn with only 123,000 miles on it. Who knows?

Thanks guys!

Edit: the brakes seemed fine when I drove it out but I'll go check the fluid.

Oriley

bradrhale · 03-09-2009, 11:47 AM

checking the fluid is not going to be enough to tell you if that is indeed the problem. take the wheel off and visually inspect as to where the fluid is coming from. small seeps are a pain to track down. go ahead and get that axle idea out of your head for now. the only way you are going to have a problem where you need a sleeve installed is if the bearing is completely toast and is allowing the axle to flop around in the tube. those sleeves are not anything that you are going to want to mess with anyways. i have taken many of them off the older stemco seals and went to the NSK (think thats what they are).
like mentioned above, check the breather. if it is open, take the wheel off and do a visual inspection.

leolkfrm · 03-09-2009, 12:28 PM

^^ As brad says change the type of seal, see if you can find one that rides in a little different position on the axle, are you overfilling the axle??

75K30 · 03-09-2009, 01:24 PM

If the seals are leaking after the truck has been parked and the axle is not hot, you can probably rule out the vent problem. This is a great place to start looking but might not be the problem.
Since the vehicles weight is directly on the axle shaft and the bearing, it is entirely possible that the shaft itself is worn out where it ride on the bearing, or the old seals have worn a groove on the sealing surface so even a brand seal will allow the oil to pass.
You could have some slop in the bearings that permit the axle to move up slightly, creating a less than desireable tolerance at the bottom of the seal.
Worn bearings can be a problem with leaks too.
Unfortunately this condition is difficult to verify because the weight of the vehicle is not on the axle during the inspection.
Look for any slop in the axle to bearing interface. Is that the correct discription??? lol.
Check to see if there is any play in the shafts. = or >100K miles might support this thoery.

Oriley · 03-09-2009, 04:22 PM

I pulled the drum off, sorry for the poor pictures.

Vent: the upper end has some sort of plastic thingie, moves freely. I couldn't get the hose off the pumpkin. I doubt the temperature going up to 40 would hardly cause pressure.

Only thing I could see was a small amount of oil on the bottom of the seal, that must be it. Brake fluid level is full.

Axle Seal: All it says on the invoice from the garage is "oil seal....4762N....$11.53 each.

I've ordered a Haynes manual but I have one more question:

To change the seal, do I have to remove the brake shoes? If I just have to drain the pumpkin, remove a bolt or clip then then yank it out I think I could manage that. I hate these golden years, this would probably be easy 30 years ago.

Thanks guys, again.

Oriley

75K30 · 03-09-2009, 04:52 PM

You do not have to remove the brakes from the backing plates. You will have to remove the diff cover to access the cross pin retaining bolt. Then you will remove the cross pin and push the axles in to get access to the "C" clips on the end of the axle itself. Once the clips are removed the axles will slide right out.
No problems there. You can inspect the bearings and the sealing surface of the shaft itself.
As I mentioned earlier, the bearings can have some slop, and the surface where the bearing rides can also be grooved. If this is the case, the seal may not actually seal when the weight of the vehicle is applied.
Speedy sleeves,a nd repair bearings are an option, but replacement axles are not expensinve.
Guess you can make that call when you get it apart.
Much luck.........

03-09-2009, 10:07 AM	#1
Oriley Full Member Join Date: Mar 2009 Location: Northern Minnesota Posts: 25	89 Chev 4 x 4 Rear Axle Seals Bought this truck 11-07 with 123,000 miles.....great shape except both rear axle seals were leaking. Brought it in for new shoes and seals. Last September I drove about 250 miles, rest of the time it sits in the garage. Drove it out of the garage a couple months ago to warm it up, everything fine. Drove it out today and there is oil on the inside of the rear drivers tire (just one spot) and a small puddle on the floor. How in the heck can a seal, with less than 300 miles on it, just decide to start leaking after 15 months? I don't get it. And why would both seals be bad when I bought it? Something else has to be going on here. The only thing I can think of is pressure building up??? Is there some sort of breather/vent on the rear end that might be plugged? I haven't a clue right now, very odd to me. Any suggestions for what I can look for? The truck is very tight and runs great except for this problem. Thanks

03-09-2009, 12:28 PM	#7
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	^^ As brad says change the type of seal, see if you can find one that rides in a little different position on the axle, are you overfilling the axle?? __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I Last edited by leolkfrm; 03-09-2009 at 03:51 PM.

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03-09-2009, 11:01 AM	#2
redneck 0991 Full Member Join Date: Oct 2008 Location: siloam springs, ar Posts: 34	there is a breather tube on the rear diff. it is on top of the diff and it runs up and connects 2 the frame. it allows the pressure in the diff 2 equalize and prevents pressure build up. i dont think that it would cause ur seals 2 leak but it's worth a shot checking it.

03-09-2009, 11:38 AM	#4
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,021	if the truck has sat up for an extended period of time, seals can dry up and become brittle causing premature failure. are you sure that this is a wheel seal and not a brake cylinder leak?? these are prone to leak as well.

03-09-2009, 11:39 AM	#5
Oriley Full Member Join Date: Mar 2009 Location: Northern Minnesota Posts: 25	A hose/fitting on top of the pumpkin.....I'll check that out. I don't have it apart yet, we have a couple days of below zero coming so I'll wait a bit. Just heard from my nephew that IF the axle is bad I can put a 'speedy sleeve' on it, whatever that is. Hard to believe the axle would be worn with only 123,000 miles on it. Who knows? Thanks guys! Edit: the brakes seemed fine when I drove it out but I'll go check the fluid. Oriley

03-09-2009, 11:47 AM	#6
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,021	checking the fluid is not going to be enough to tell you if that is indeed the problem. take the wheel off and visually inspect as to where the fluid is coming from. small seeps are a pain to track down. go ahead and get that axle idea out of your head for now. the only way you are going to have a problem where you need a sleeve installed is if the bearing is completely toast and is allowing the axle to flop around in the tube. those sleeves are not anything that you are going to want to mess with anyways. i have taken many of them off the older stemco seals and went to the NSK (think thats what they are). like mentioned above, check the breather. if it is open, take the wheel off and do a visual inspection.

03-09-2009, 01:24 PM	#8
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	If the seals are leaking after the truck has been parked and the axle is not hot, you can probably rule out the vent problem. This is a great place to start looking but might not be the problem. Since the vehicles weight is directly on the axle shaft and the bearing, it is entirely possible that the shaft itself is worn out where it ride on the bearing, or the old seals have worn a groove on the sealing surface so even a brand seal will allow the oil to pass. You could have some slop in the bearings that permit the axle to move up slightly, creating a less than desireable tolerance at the bottom of the seal. Worn bearings can be a problem with leaks too. Unfortunately this condition is difficult to verify because the weight of the vehicle is not on the axle during the inspection. Look for any slop in the axle to bearing interface. Is that the correct discription??? lol. Check to see if there is any play in the shafts. = or >100K miles might support this thoery.

03-09-2009, 04:22 PM	#9
Oriley Full Member Join Date: Mar 2009 Location: Northern Minnesota Posts: 25	I pulled the drum off, sorry for the poor pictures. Vent: the upper end has some sort of plastic thingie, moves freely. I couldn't get the hose off the pumpkin. I doubt the temperature going up to 40 would hardly cause pressure. Only thing I could see was a small amount of oil on the bottom of the seal, that must be it. Brake fluid level is full. Axle Seal: All it says on the invoice from the garage is "oil seal....4762N....$11.53 each. I've ordered a Haynes manual but I have one more question: To change the seal, do I have to remove the brake shoes? If I just have to drain the pumpkin, remove a bolt or clip then then yank it out I think I could manage that. I hate these golden years, this would probably be easy 30 years ago. Thanks guys, again. Oriley

03-09-2009, 04:52 PM	#10
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	You do not have to remove the brakes from the backing plates. You will have to remove the diff cover to access the cross pin retaining bolt. Then you will remove the cross pin and push the axles in to get access to the "C" clips on the end of the axle itself. Once the clips are removed the axles will slide right out. No problems there. You can inspect the bearings and the sealing surface of the shaft itself. As I mentioned earlier, the bearings can have some slop, and the surface where the bearing rides can also be grooved. If this is the case, the seal may not actually seal when the weight of the vehicle is applied. Speedy sleeves,a nd repair bearings are an option, but replacement axles are not expensinve. Guess you can make that call when you get it apart. Much luck.........