Rear Main Seal
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Rear Main Seal
1992, 150, 351 155,000. I had the rear main seal changed in Jan 05,first one leaked within two weeks,mechanic put in another one along with some kind of sleeve. Didn't notice anything until a couple of months ago that it looks like it is starting to leak again.I have only put 3,000 miles on the truck since it was changed.The Mechanic told me because of the high miles and there being to much play in the bearings that that is what is wearing out the seal. What do you guys think?
Posting Guru
Joined: Sep 2005
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From: Kiefer, Northeastern Okla
Excessive crankshaft end-play, a sign of a worn thrust bearing, can indeed cause wear of the seal. Also, improper installation of the last seal can too. Did he check crank end-play? If not, and your oil pressure is fine, how does he know your bearings are worn? I'm curious about the "sleeve". Was it supposed to be a cure for worn rear main bearings?
Posting Guru
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From: Kiefer, Northeastern Okla
Sorry, I still don't get it. The seal goes IN a groove. Now, he may be talking about something else entirely, but I've personally never had to have a sleeve installed there. Now, he must have checked the endplay or he's got really sharp eyes because it's generally in the .004 to .008 in. zone. That's thousandths of an inch. A bad number would be anything over .012 in. If he can "wiggle" it around without measuring, you've definitely got bearing problems. How's your oil pressure? -Pete P.S. Hate to ask, but do you trust your mechanic?
Cargo Master
Joined: Dec 2003
Posts: 2,182
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From: Saint Augustine, FL
The sleeve is a repair item that is commonly used to fix a rear crank seal that has worn a groove in the surface of the crankshaft where the lip of the seal rides. Just changing the seal doesn't work because the new seal leaks where the grove is. The sleeve is just a thin steel band that slides over the end of the crankshaft so the seal has a new surface to ride on.
A more knowledgeable mechanic would have not driven the new seal in so deep so that it road a little further out on the crank so it would miss the grove and have a nice smooth surface to seal against.
Regardless, if the thrust bearing is worn and the crankshaft is moving fore/aft then nothing will fix the rear seal leak. You do need to have the crank's thrust movement checked carefully with a dial indicator. If its out of spec you may be able to just change the main bearings and solve the problem. Replace the oil pump while you are in there.
Steve
'95 Clubwagon XLT
A more knowledgeable mechanic would have not driven the new seal in so deep so that it road a little further out on the crank so it would miss the grove and have a nice smooth surface to seal against.
Regardless, if the thrust bearing is worn and the crankshaft is moving fore/aft then nothing will fix the rear seal leak. You do need to have the crank's thrust movement checked carefully with a dial indicator. If its out of spec you may be able to just change the main bearings and solve the problem. Replace the oil pump while you are in there.
Steve
'95 Clubwagon XLT
Mountain Pass
Joined: Dec 2005
Posts: 133
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From: Mackinaw City, MI
If the mechanic didn't put some kind of sealer on the flywheel/flexplate bolts before he put them back in, you will have a leak in that same area, but might not be the seal itself. Oil will travel through the threads of the bolts and leak in the bellhousing area.
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Cargo Master
Joined: Dec 2003
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From: Saint Augustine, FL
Originally Posted by Tech-man
If the mechanic didn't put some kind of sealer on the flywheel/flexplate bolts before he put them back in, you will have a leak in that same area, but might not be the seal itself. Oil will travel through the threads of the bolts and leak in the bellhousing area.
Steve
'95 Clubwagon XLT
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Elder User
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From: Troy,NY
Originally Posted by Clubwagon
I am pretty sure those are blind holes and do not go through to the oil passages inside the crankshaft. We changed hundreds, if not thousands of flywheels at my shop and I don't ever remember putting sealer on flywheel bolts and we had no trouble with leaks.
Steve
'95 Clubwagon XLT
Steve
'95 Clubwagon XLT
Mountain Pass
Joined: Dec 2005
Posts: 133
Likes: 1
From: Mackinaw City, MI
Whoops, my mistake....O.E. 5.0 cranks have the holes drilled all the way through the rear flange, 5.8's do not. Thread locker acts as a sealant just the same. Teflon, rtv silicone work also to stop the oil from getting through.
