Rear main seal replacement
Thread Starter
Pro
Joined: Jun 2011
Posts: 588
Likes: 41
From: Ohio
Rear main seal replacement
Does anyone have an idea on how much a good shop would charge to replace the 2 piece rear main seal on my 350 78 SA? I know I could do it but just don't want to deal with the mess plus it would get done much faster.
thanks, Lonzoo
thanks, Lonzoo
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
All due respect, but. Please don't think I am busting your chops.
Just put a piece of cardboard on the garage floor under it. Change it monthly. A bit of leakage past the rear seal is very common on our old smallblocks. That's why Chevrolet changed the seal design.
Just put a piece of cardboard on the garage floor under it. Change it monthly. A bit of leakage past the rear seal is very common on our old smallblocks. That's why Chevrolet changed the seal design.
Drifting
Joined: Jun 2010
Posts: 1,781
Likes: 15
From: Oxford Ohio
Doing it yourself, will or could give you an idea of the condition of your bottom end. When ever I do that job, I always photo the bearings to show the customer. If you're considering an oil pump upgrade or change, this would be the time to do it.
Could be a good time to replace the front seal too. They are, most likely the same age. Big pain in the rump to fix the rear and a short time later the front springs a slow leak. While you're under there and fixing things get everything done you can.
Could be a good time to replace the front seal too. They are, most likely the same age. Big pain in the rump to fix the rear and a short time later the front springs a slow leak. While you're under there and fixing things get everything done you can.
Instructor
Joined: Jul 2012
Posts: 156
Likes: 0
You should try it yourself. I was told 600.00 to do the job here. (In Ga).
I looked up the part and it was only 30.99 (Rear Seal) Auto Zone Part # 2947 Brown seal. (There are other parts you will need as well but you will still save money by doing it yourself).
I figured if I could change this myself I would save a lot. So I did and It works great. I did it with out a lift on my back in the garage with ramps. Had a great time listening to some country music smelling oil and turning wrenches.
Try it yourself. I think that's why it's called The American Muscle. If you decide to do it yourself. Look through the forum for advice.(There are alot of guys and gals on here that will help you through it! There are pics and very good suggestions on how to change it fast and accurately. You are at the right Forum! Good Luck!
I looked up the part and it was only 30.99 (Rear Seal) Auto Zone Part # 2947 Brown seal. (There are other parts you will need as well but you will still save money by doing it yourself).
I figured if I could change this myself I would save a lot. So I did and It works great. I did it with out a lift on my back in the garage with ramps. Had a great time listening to some country music smelling oil and turning wrenches.
Try it yourself. I think that's why it's called The American Muscle. If you decide to do it yourself. Look through the forum for advice.(There are alot of guys and gals on here that will help you through it! There are pics and very good suggestions on how to change it fast and accurately. You are at the right Forum! Good Luck!
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
For years I had a leaking rear main seal. Had a rubber mat under the car that always had oil on it. Car would smell of the oil after daily use. Then I decided to put Blue Devil Rear Main Sealer in the car and have not had a drop of oil since - over a year now. Its worth $15 to try.
Last edited by Wrecked82; Feb 19, 2013 at 03:10 PM.
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Thread Starter
Pro
Joined: Jun 2011
Posts: 588
Likes: 41
From: Ohio
thanks for all the responses. I won't pay $600 for the job to be done but I may consider $400 if they would do the front also. At this point I will give the BlueDevil sealer a shot. Will let you know how the stop leak works.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
To be fair to those who have given you estimates, that front exhaust Y-pipe will have to come down. You are looking at the exhaust studs coming off and replaced, the Y-pipe and the extension as well. All that before you get to the oil pan. So don't pre-judge the costs as being high. Been there, done it.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
Doing it yourself, will or could give you an idea of the condition of your bottom end. When ever I do that job, I always photo the bearings to show the customer. If you're considering an oil pump upgrade or change, this would be the time to do it.
Could be a good time to replace the front seal too. They are, most likely the same age. Big pain in the rump to fix the rear and a short time later the front springs a slow leak. While you're under there and fixing things get everything done you can.
Could be a good time to replace the front seal too. They are, most likely the same age. Big pain in the rump to fix the rear and a short time later the front springs a slow leak. While you're under there and fixing things get everything done you can.
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
For years I had a leaking rear main seal. Had a rubber mat under the car that always had oil on it. Car would smell of the oil after daily use. Then I decided to put Blue Devil Rear Main Sealer in the car and have not had a drop of oil since - over a year now. Its worth $15 to try.
Pro
Joined: Nov 2009
Posts: 667
Likes: 7
From: Milpitas Calyfornua
For years I had a leaking rear main seal. Had a rubber mat under the car that always had oil on it. Car would smell of the oil after daily use. Then I decided to put Blue Devil Rear Main Sealer in the car and have not had a drop of oil since - over a year now. Its worth $15 to try.
Burning Brakes
Joined: Apr 2007
Posts: 1,186
Likes: 41
From: Pinecrest FL
2015 C3 of the Year Finalist
For the past 2 years, I thought I had a leaky rear main in my 69. Had to change out the cardboard box on the garage floor every 3-4 months.
I looked into getting the rear main done a few months ago because I knew I had to do a PV at the kissimmee regional and the leak would be a failure that I couldnt fix.
A few days before I was going to do the rear main, I cleaned off the drivers side rear of the block so the casting numbers would be clearly visible. Within 2-3 days of driving the rear of the block was covered in oil again.
What I thought was a leaky rear main seal was actually a small leak at the head gasket. I smeared some RTV around the area and it took care of the problem. I guess I will eventually have to do the head gasket(s), but problem solved for now.
Gary
I looked into getting the rear main done a few months ago because I knew I had to do a PV at the kissimmee regional and the leak would be a failure that I couldnt fix.
A few days before I was going to do the rear main, I cleaned off the drivers side rear of the block so the casting numbers would be clearly visible. Within 2-3 days of driving the rear of the block was covered in oil again.
What I thought was a leaky rear main seal was actually a small leak at the head gasket. I smeared some RTV around the area and it took care of the problem. I guess I will eventually have to do the head gasket(s), but problem solved for now.
Gary