Changing main seals while engine still in blazer - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Eyegore · 08-20-2012, 03:20 PM

Help my sons 78 k5 appears to need the main seals replaced, has anyone done it while it was still in the truck? Its a k5 with a 8" lift 400 cid engine.

manimal · 08-21-2012, 09:05 AM

Since it has a lift the it shouldt be too hard. Drop pan,unbolt rear main cap. With an awl or small flat screwdriver,push the old main seal out,being careful not to touch the crank. Then push the new one in place(block side) and replace the main cap side. The re-install main cap(use some assembly lube on bearing) and torque to spec. Get a Felpro 1pc oil pan gasket,will make life WAY EASIER!
ALSO put a light coat of oil on the seal lip so it doesnt run dry.

gchemist · 08-21-2012, 09:15 AM

Follow these instructions: http://www.73-87.com/7387garage/drivetrain/rearseal.htm

DetroitIron · 08-21-2012, 08:22 PM

Quote:

Originally Posted by manimal

Since it has a lift the it shouldt be too hard. Drop pan,unbolt rear main cap. With an awl or small flat screwdriver,push the old main seal out,being careful not to touch the crank. Then push the new one in place(block side) and replace the main cap side. The re-install main cap(use some assembly lube on bearing) and torque to spec. Get a Felpro 1pc oil pan gasket,will make life WAY EASIER!
ALSO put a light coat of oil on the seal lip so it doesnt run dry.

With the transmission removed or can this be done without removing trans?

mud.man.rj · 08-21-2012, 08:26 PM

Just pull the inspection plate from trans then do as stated earilier, no big deal, don't do it hot let the oil drip down into the pan for awhile not right after running it that way it isn't drip drip dripping off the crank on your face. Just did one and a HV oil pump too.

Eyegore · 08-25-2012, 12:59 AM

Thanks everyone, he is ging to try it next week. Thanks again!!

08-20-2012, 03:20 PM	#1
Eyegore What Hump? Join Date: Apr 2003 Location: New River AZ Posts: 2,009	Changing main seals while engine still in blazer Help my sons 78 k5 appears to need the main seals replaced, has anyone done it while it was still in the truck? Its a k5 with a 8" lift 400 cid engine. __________________ Lil red 86 c-10 99 Sub 78 Camper Special w/ 454

08-21-2012, 09:05 AM	#2
manimal Registered User Join Date: Oct 2006 Location: Southern Kalifornia Posts: 3,066	Re: Changing main seals while engine still in blazer Since it has a lift the it shouldt be too hard. Drop pan,unbolt rear main cap. With an awl or small flat screwdriver,push the old main seal out,being careful not to touch the crank. Then push the new one in place(block side) and replace the main cap side. The re-install main cap(use some assembly lube on bearing) and torque to spec. Get a Felpro 1pc oil pan gasket,will make life WAY EASIER! ALSO put a light coat of oil on the seal lip so it doesnt run dry. __________________ ------------------------------------------------------ -Lance 2000 Chevy C2500, 5.7, 4L80e 1999 Suburban K2500, 7.4, 4L80e 1980 Camaro..son's car...PROJECT

08-21-2012, 09:15 AM	#3
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: Changing main seals while engine still in blazer Follow these instructions: http://www.73-87.com/7387garage/drivetrain/rearseal.htm __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

08-21-2012, 08:26 PM	#5
mud.man.rj Registered User Join Date: Dec 2011 Location: Creighton Sask. Canada Posts: 4,121	Re: Changing main seals while engine still in blazer Just pull the inspection plate from trans then do as stated earilier, no big deal, don't do it hot let the oil drip down into the pan for awhile not right after running it that way it isn't drip drip dripping off the crank on your face. Just did one and a HV oil pump too.

08-25-2012, 12:59 AM	#6
Eyegore What Hump? Join Date: Apr 2003 Location: New River AZ Posts: 2,009	Re: Changing main seals while engine still in blazer Thanks everyone, he is ging to try it next week. Thanks again!! __________________ Lil red 86 c-10 99 Sub 78 Camper Special w/ 454



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