Not a lot of fun, but doable.
rear main seal replacement
Thread Starter
Racer
Joined: May 2009
Posts: 316
Likes: 1
rear main seal replacement
My 68 327 has started leaking oil. I have checked valve cover areas etc. but it seems to be coming from between the bell housing and engine block. It may be my rear main seal. Anyone replace one of these themselves on an early C3 like mine? DIY or take it to the shop?
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
Melting Slicks
Joined: Jul 2006
Posts: 2,291
Likes: 492
From: Salmon Arm, BC
I just did this on mine last month, and on a friends corvette last year.
It's easy to do with the engine still in the car.
Here's the coles notes version....
-Drop the steering gear, pull the starter, pull the pan, pull the oil pump, pull the rear main cap....change seal and reassemble.
Don't buy a cheap seal, get the good one from Fel-pro 2912
One day job with a hoist, probably 2 days laying on your back....
It's easy to do with the engine still in the car.
Here's the coles notes version....
-Drop the steering gear, pull the starter, pull the pan, pull the oil pump, pull the rear main cap....change seal and reassemble.
Don't buy a cheap seal, get the good one from Fel-pro 2912
One day job with a hoist, probably 2 days laying on your back....
Race Director
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
A good 20 years ago my 66 with a
327 i dropped in started really leaking bad rear main seal,
I ran it up on ramps, recall having to disconnect steering rod, drop the pan and that related fun, and changing the seal was fast and easy, and i didnt line up where the seal meets top and bottom with main cap to give extra protection, i pushed one end if the seal around more, staggered the breaks,
It worked great did it alone in a long day, but that car was stick with no power stuff and if to do it again, yep, would pull the engine, it wasnt fun in my back,
327 i dropped in started really leaking bad rear main seal,
I ran it up on ramps, recall having to disconnect steering rod, drop the pan and that related fun, and changing the seal was fast and easy, and i didnt line up where the seal meets top and bottom with main cap to give extra protection, i pushed one end if the seal around more, staggered the breaks,
It worked great did it alone in a long day, but that car was stick with no power stuff and if to do it again, yep, would pull the engine, it wasnt fun in my back,
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Purchase a Viton rear seal...comes in two halves. READ INSTRUCTIONS CAREFULLY AND FOLLOW THEM. Offset each half-seal about 1/8" from the engine splitline so that the splits between the seal halves don't line up with the engine block splitline.
This is NOT a difficult job. Use care when inserting the upper seal half so that the sealing lip is not damaged (instructions will explain).
Did mine about 10 years ago...nary a drop since.
This is NOT a difficult job. Use care when inserting the upper seal half so that the sealing lip is not damaged (instructions will explain).
Did mine about 10 years ago...nary a drop since.
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Thread Starter
Racer
Joined: May 2009
Posts: 316
Likes: 1
Thanks for the info. Is there a tool to press the top seal out and put the new one in? It looks like it can be a bit tricky to remove?
Purchase a Viton rear seal...comes in two halves. READ INSTRUCTIONS CAREFULLY AND FOLLOW THEM. Offset each half-seal about 1/8" from the engine splitline so that the splits between the seal halves don't line up with the engine block splitline.
This is NOT a difficult job. Use care when inserting the upper seal half so that the sealing lip is not damaged (instructions will explain).
Did mine about 10 years ago...nary a drop since.
This is NOT a difficult job. Use care when inserting the upper seal half so that the sealing lip is not damaged (instructions will explain).
Did mine about 10 years ago...nary a drop since.
Melting Slicks
Joined: Jul 2006
Posts: 2,291
Likes: 492
From: Salmon Arm, BC
I used a bit of brakeclean to clean any oil residue and then lubed the new seal around the edge that contacts the crankshaft and then install. Yes using the litle tool that is supplied with the seal is essential to the job going smoothly, use it like a shoehorn.
This is one of the better seal out there to use, think its worth the extra money.
I https://www.summitracing.com/int/par...make/chevrolet
Last edited by OMF; Apr 9, 2017 at 11:50 PM.
Thread Starter
Racer
Joined: May 2009
Posts: 316
Likes: 1
Thanks for the info, Cant imagine why you'd have to pull a motor just to replace these seals! Sounds crazy.
Its not tricky to remove at all, I just used a large diameter punch that was close to the same size of the seal end and tapped the seal to get it started. It just spins out around its own groove, and once started its easy to grab with some plyersand pull it out.
I used a bit of brakeclean to clean any oil residue nad then lubed the new seal around the edge that contacts the crankshaft and then install. Yes using the litle tool that is supplied with the seal is essential to the job going smoothly, use it like a shoehorn.
This is one of the better seal out there to use, think its worth the extra money.
I https://www.summitracing.com/int/par...make/chevrolet
I used a bit of brakeclean to clean any oil residue nad then lubed the new seal around the edge that contacts the crankshaft and then install. Yes using the litle tool that is supplied with the seal is essential to the job going smoothly, use it like a shoehorn.
This is one of the better seal out there to use, think its worth the extra money.
I https://www.summitracing.com/int/par...make/chevrolet
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
Yes, no reason to remove the engine. Not my favorite job, but far less work than removing the engine. Do your homework and get the best seal you can. There are several different seals available and they are not created equal. I don't recall the details, but I have used the good ones and the cheap ones, and the good ones are definitely worth the money.
Pro
Joined: Sep 2016
Posts: 720
Likes: 205
From: Michigan
There are several versions out there - Fel-Pro seems to be the most recommended. But they offer a single lip, dual lip, and an offset lip version (supposedly to slightly shift the seal surface on the crank, if there has been a groove worn in by the old seal).
How to know which one to choose??
(mine is a '69 350, not the '68 327 of the O.P.)
How to know which one to choose??
(mine is a '69 350, not the '68 327 of the O.P.)
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
There are several versions out there - Fel-Pro seems to be the most recommended. But they offer a single lip, dual lip, and an offset lip version (supposedly to slightly shift the seal surface on the crank, if there has been a groove worn in by the old seal).
How to know which one to choose??
(mine is a '69 350, not the '68 327 of the O.P.)
How to know which one to choose??
(mine is a '69 350, not the '68 327 of the O.P.)
Advanced
Joined: Oct 2011
Posts: 66
Likes: 11
From: Stowe Vermont
I'd take off the dust cover on the bell housing to be sure there is oil in the bell housing first. The rear of the passenger side valve cover can leak oil down that way. You may just need to tighten the valve cover bolts. Speaking from experince...
1st Gear
Joined: Mar 2019
Posts: 1
Likes: 0
Rear main replacement
I did mine today. It took about 3 hours. It's a straight forward job. I used the one piece oil pan gasket and the felpro offset seal. I had no issues at all. You just need hand tools and a torque wrench.
Last edited by Sbrown6422; Mar 30, 2019 at 05:15 PM.
Le Mans Master
Joined: Oct 2010
Posts: 6,937
Likes: 848
From: melbourne florida
2023 C3 of the Year Finalist - Modified
Takes about an hour and a half with these new electric tools. I put a deep milodon pan and melling select pump on at the same time. The felpro offset seal is a great idea. Put assembly lube on your rear main bearing .pulling the engine is nuts it's very straight forward..