Question: 81 Rear Main Seal Repair

[tgg901]

My 81 needs a new rear main seal and the garage where I have most of my mechanical work done says that to replace the rear main seal and valve cover gaskets would take approx. 8 hours because of removing trans, disconnecting motor mounts and raising engine to remove the oil pan. I also talked to a person in Atlanta where I buy my parts and he said that you don't need to disconnect the motor mounts and raise the engine or mess with the transmission that the oil pan comes right out and was only a couple hours of work. Can anyone please give me some advice on this matter. 8 hours of labor will come close to $1000 which I think is more than twice what it should cost.

 

[6880 Mike]

Get a second and, possibly, a third estimate.

 

[minifridge1138]

You do not have to remove the engine to change the rear seal.

You do have to remove the oil pan. In order to do that, you may need to disconnect parts of the steering linkage.

I wouldn't go to a garage that wants to pull the motor. They obviously like to over-charge.

Good luck!

 

[wishuwerehere82]

Go someplace else that works on vettes.
The steering relay rod will need to be dropped from the pitman arm on the steering box and the idler arm, to drop the relay rod, so they can get to the pan.
The oil seal is in two pieces, one of which is in the block and can be removed with a special tool.

 

[JohnZ]

2-3 hour job at most, and you don't have to do anything except lower the steering linkage to get the pan off. Also helps to turn the engine so the timing index line on the balancer is at 5 o'clock (as viewed from the front) - that gets the front counterweight on the crank up out of the way and gives you more clearance to get the pan off.

 

[Vette79]

2-3 hour job at most, and you don't have to do anything except lower the steering linkage to get the pan off. Also helps to turn the engine so the timing index line on the balancer is at 5 o'clock (as viewed from the front) - that gets the front counterweight on the crank up out of the way and gives you more clearance to get the pan off.

Exactly, just did this this past year. The only other thing to add would be to let you know that the torque converter cover needs to be removed as well which is fairly easy if you have stock exhaust. If you are replacing the rear main seal it definitely would be a great time to replace the oil pump and pickup if needed.

 

[TimAT]

As others have said here, drop the steering linkage to get the pan down and go for it. Here's a sort of a guide as to how to change the seal.


Once you have the pan down, remove the oil pump and pickup. Remove the rear main cap. The lower half of the seal is right there. Don't scratch the bearing. Take a small screwdriver and pop the lower half out of the cap, then use the screwdriver, (I have one that I did a little bit of grinding on so it's got a better flat end) and push on the exposed end of the upper half of the seal. You may hve to tap it a little bit to break the upper seal loose. Drive it out until you can get a good grip on it and then just walk it on out. Now the old seal is out, clean the block and the seal groove with something like brake cleaner, just hose it out really well.

The trick part is next. GM and the aftermarket have 3 different widths of rear seals. The difference in them is from the dust lip on the back to the wiper lip on the forward side of the seal. The best (and widest one) is the one you need to find. The biggest distance between the two lips. You may have to hunt for it. GM had them all under the same part number, but there are different ones.


Take the rear main cap to your bench grinder and use the wire wheel on the mating surfaces adjacent to the seal. Don't get so far forward to catch the bearing. Buff the cap, get it really clean. Then hose it down with the brake cleaner too. Let it dry while you install the upper half of the seal.

In the package there is a little plastic "spoon". Use it to install BOTH the upper and lower halves. Put a little bit of grease on the lips of the upper seal. If you don't, the rib on the inside of the seal gets sliced off and will seep underneath the seal.

Once you have the lower seal in place, wipe a little bit of grease on the lips of that seal too. Apply a very thin coat of form-a-gasket or an anerobic sealer or something like that on the cap next to the seal. Just above the pan gasket groove. Install the cap, torque to specs and install the oil pump, and pan.

I've done literally hundreds of rear main seals over 15+ years of working for Chevy dealers and NEVER had to do the same one twice.

I hope this helps and I also hope I didn't confuse the issue for you. If you have any questions, just drop me a note..