Rear Main Seal

[Ken C]

I'm about to put in my new clutch setup (finally), thought while it was right there, that I should put in a new seal. Looks straight forward enough, but the manual talks about slide hammers to remove the old, and a special seal installing tool. Can't you just pry/scrape out the old one and tap in a new one with a heavy plate to apply uniform pressure? Am I way off? I just don't want this to be one of those looks too easy and becomes a nightmare kinda' deals

Thanks

[jhorton]

You have the right idea. I used a small screwdriver to pierce the old seal and pry it out. My new one came with an installation tool. Put some thread sealer on the flywheel bolts, or you will have an oil leak and call your rig ugly names.

[Baradium]

it's much easier to fix leaks when you have all that stuff off... don't forget to buy a new oil pan gasket too!

[Dennis Bernth]

No special tools needed. You need to have a way to pop it out, as jhorton says, then as long as you tap it in evenly all the way around and make sure it is seated to a uniform depth you will be fine. The Fel-Pro comes with a thin plastic ring that serves as a protector and guide to install the lip over the crank; however, the seal itself is a Teflon type that is supposed to be installed dry, vs. normal seals being installed oiled. I've used the Felpro a couple times and it works well. There are also two rubber 'rods' that are part of the seal kit; they install from the bottom of the rear main. You about have to drop the rear main cap to remove the old ones though, which means if you want to install those (a good idea unless you know they have been replaced in the last twenty years or so) you will need the pan gasket Ryan talked about. It's not a bad idea to drop the pan anyhow and do a cleaning and inspection. Good time to do the two rear core plugs that are behind the bellhousing and prevent any future surprises from them also.....

[Baradium]

what's the function of those "rods" are they plugs?

Ryan,

They are a type of oil seal. In fact they are called side seals (in the book "Rear Main Bearing Cap Side Oil Seals"). They keep oil from seeping out at the bottom of the bearing cap. My 78-80 engine section, CGES-160, page 49 shows a pic of one being installed. The manual says to use a locally made tool out of welding rod to install them but I just took an old small Phillips screwdriver (because it has a round shaft) and ground the tip to a rounded shape with no sharp point. I coated them with engine oil and they right went in.

If they have never been replaced they are probably brittle and difficult to get out, as Dennis mentioned. They can break off inside their hole. I loosened the bearing cap bolts and spyayed some WD-40 in where I could.

As far as installing the rear main seal, I used a roll of duct tape as an installation tool, the idea courtesy of my son Darren. It went right in. It's been in about nine years.

[Ken C]

Thanks, sounds like what I was thinkin'.....taking off the pan will give me a chance to knock out the dent I put in jacking up the motor when removing the tranny&case ....about sealing the flywheel bolts, are we talking red Loctite or more like a liquid/tape teflon type seal?

Thanks again

[Dennis Bernth]

I think that's somewhat open to your personal preference. I wouldn't do the teflon tape, if any of it comes loose it could jam up an oil passage. For the same reason, I wouldn't use RTV. Some guys have used Loctite, I have used Permatex #2 and Permatex Aviation Form-a-Gasket, both worked fine with no leaks, and you can pull it back apart if need be. I don't think it's all that critical, it isn't in a 'pressure' situation, but that area is exposed to oil and will leak if it isn't sealed somehow. As for the side seals, they are as Doug described; they are what seals up the 'parting line' where the upper and lower rear main mate that would be prone to leak to the rear of the engine. I 'made' the tool described in the service manual, took about two minutes and an old welding rod. FWIW, some guys cut off the 'flange' at the tops of the side seals after they are installed; I haven't, in three different engines, and never had a problem doing it that way. My thoughts were the pan gasket would absorb the small height difference, and leaving the flange on would keep the seals from 'shrinking' deeper into the rear main as they age, and maybe leaking. Don't know if my reasoning is valid, but my engines haven't leaked yet.....

I'm with Dennis on not cutting off the side seal "flanges". Mine haven't leaked either.

[Hooper]

Originally posted by Ken C
Thanks, sounds like what I was thinkin'.....taking off the pan will give me a chance to knock out the dent I put in jacking up the motor when removing the tranny&case ....about sealing the flywheel bolts, are we talking red Loctite or more like a liquid/tape teflon type seal?

Thanks again

I used some RS on those threads.