Rear main seal

[Mark Pietz]

I know this has been beat to death, but now it's my horse. Was ordering parts from Rock Auto today, and got the Felpro rear main (teflon) w/side seals. Price was good. What is the best way to install one of these? Many years ago I tried and failed and gave up, but now I'm committed to making it work.

????

[Brian Huver]

Mark,
I just replaced the rear main seal on my 73 Wagon Master. It has a 345 with a TF 727 tranny. What kind of vehicle are planning on doing this to? The reason I ask is because I was able to leave my engine in the truck because I have a dog house over the tranny that I could take off.
I bought a Felpro seal as well, and I heard they are not the best, but I did not have any leaks at all. I had to throw my seal in the freezer for a few hours, and then I tapped it in with a dead blow hammer and a 4" sch40 adapter from Home Depot. It fit perfect around the seal. The hard part is keeping the inside sleeve from coming out when you are tapping it in. I also replaced the two elongated seals that came with the rear main as well.
I have a blog on what I did if you want to take a look at it, it is on my homepage here.

Good luck,

Brian

[Doc Stewart]

I just installed a Felpro RMS that I had for several years [misplaced it]. It came with a plastic sleeve that allows the seal to slide over the crank - then you pull out the sleeve.

Tap the seal in with a plastic pipe joint from the hardware store or a large socket from your 3/4 drive set or your axle nut set or just use a plastic or copper punch and tap evenly all around until it sets in evenly - harder than it sounds.

Make such a sleeve from a 'Big Gulp' cup or the like. No need to lube it.

CHECK FIRST: if your crank has a groove in it where the old seal has ridden. If so, make a spacer out of a carb-to air filter gasket. It won't be the right diameter so cut little bits out of it until it fits in there. It doesn't seal anything so the cut doesn't matter. Install this spacer first. This will hold the new seal out just enough to ride on fresh metal.

The FelPro Teflon seal is to be installed on a dry surface whereas other types should have a smear of oil or grease or assembly lube on the crank surface.

I have heard others diss the FelPro RMS but I have had no trouble with them. I suspect they were installed on a grooved crank and therefore leaked.

[Mark Pietz]

Doc,
Thanks for the info. No, the crank has been polished so that surface is now good, which should make for better results. I'll look at what comes in the box to see exactly what you mean in installing this.

Gettin' closer to gettin' my engine together.

[Thomas]

Originally Posted by Doc Stewart

CHECK FIRST: if your crank has a groove in it where the old seal has ridden. If so, make a spacer out of a carb-to air filter gasket. It won't be the right diameter so cut little bits out of it until it fits in there. It doesn't seal anything so the cut doesn't matter. Install this spacer first. This will hold the new seal out just enough to ride on fresh metal.

---I install a ready repair sleeve on all our cranks, worn or not, simply because it's easier to replace a sleeve than a crank. This is the first time I heard you mention this trick Doc & I thank you for the tip you gave here. Nice one for sure and while I doubt we'll lose the manufacturing of the rear crankshaft seal or repair sleeve (used in Honda's & transport trucks as well), it is certainly something one can do in a pinch. Thanks again.

---I also replace the Side Plugs as well. Those AFAIC would be discontinued long before the rear crankshaft seal, so I'd rather not be caught with them being 40+ years old.

---Don't forget to clean & coat the flywheel bolts with a thread sealer. Not a thread locker, just a sealer, to prevent the crankcase oil from leaking past the threads. The crankshaft flange's bolt holes are a through-type & need to be sealed. If not sealed, they will leak. I use Indian Head (AKA Old no.9) from Permatex on those.

[Mark Pietz]

The reason I bought the Felpro was because of the side seals. I haven't see the side seals in a National or Victor kit (that was my real preference). I'm sure they're out there, but Rockauto didn't list it. I toyed with the idea of using a National and squirting RTV into those holes with the block inverted, then....naaah, just get the kit and see how it works out. Already know about Permatex on the threads of the flywheel bolts.

[Doc Stewart]

The trick for installing those side seals is to take piece of 3/32 brazing or welding rod and heat the end to form a little ball [so as not to push through the seal] then push the side seals home.

[jauringer]

Originally Posted by Doc Stewart

CHECK FIRST: if your crank has a groove in it where the old seal has ridden. If so, make a spacer out of a carb-to air filter gasket. It won't be the right diameter so cut little bits out of it until it fits in there. It doesn't seal anything so the cut doesn't matter. Install this spacer first. This will hold the new seal out just enough to ride on fresh metal.

Interestingly enough, when I purchased a Corteco RMS set from Rock Auto, it came with a .070 spacer in it to push the seal out on fresh metal.

And too, when Doc says "no need to lube it" that means don't lube it. The Felpro seal has to go on dry.

[jeff campbell]

that seal/spacer comes in the felpro engine kit also.take a welding rod an knock off the flux coating.,also works good for installing the side rubber seals.jeff.