rear main seal leak?

[Thumper]

This is in a '72 CJ5 AMC 258 i6 / 4.2l /3spd, it's dripping from the area between the tranny and block, there's the plate, dust shield for the clutch maybe. I'm sure it's a rear main seal, or if lucky a pan gasket. Its a steady drip when idling, and it's enough that I'd rather fix it, it drips in my garage and anywhere I stop, drip drip drip. What's the easiest way to go about this? Can I just pull the pan and the rear main and swap in a few hours? I'm hoping the crank isn't worn. All I know is that I traded for it a couple years ago, the vin shows it's all stock, miles shows 65,000 so it may be 165,000 or 265,000. It could be stock and never rebiult, but it doesn't smoke a bit that I can see and besides it being cold natured it seems good, makes a slight tick.

 

[BusaDave9]

Remove the oil pan. Remove the rear main bearing. You have a 2 piece seal. The piece in the main bearing you removed is easy to replace. The top half is tight on top of the crank shaft. To make it easier to remove loosen up the other bearing caps. No need to completely remove the caps. Then you can press one side of the seal out. Once you have enough out that you can grab it with a pair of pliers you should be able to pull it out. Then push the new seal back in by putting it under the crankshaft and pushing it in.

 

[Rollbar]

Also remove coil wire and have someone rotate the crank and it comes out easier.

Get some 3M Super 300 (I used black) and use it to go back w/on the seal, but I used RTV on the chamfer edges. Also get a one piece gasket.

 

[Thumper]

Can the rear seal and pan gasket be had at a local parts store?

 

[BusaDave9]

Can the rear seal and pan gasket be had at a local parts store?

Yes

 

[Tommy]

Before replacing the rear main seal, you might want to check and see if the oil is coming from the valve cover gasket first. It would leak down the rear of the engine and come out in the same place. I replaced my rear main seal only to find that it wasn't the problem. If there is no oil running down the rear of engine then the above posts reflect the way I replaced my seal.

Tommy

 

[One1TonCJ7]

Remove the oil pan. Remove the rear main bearing. You have a 2 piece seal. The piece in the main bearing you removed is easy to replace. The top half is tight on top of the crank shaft. To make it easier to remove loosen up the other bearing caps. No need to completely remove the caps. Then you can press one side of the seal out. Once you have enough out that you can grab it with a pair of pliers you should be able to pull it out. Then push the new seal back in by putting it under the crankshaft and pushing it in.

The 2-piece seal. is it the same in an 80 CJ7 ? w/ AMC 304 / 3spd.

 

[BusaDave9]

No the rear main seal in a AMC 258 i6 / 4.2l is not interchangeable with a AMC 304 .

 

[Thumper]

Well, it's the rear main seal. I have to get a cherry picker tomorrow because there's two oil pan bolts behind the passenger motor mount and I have to pull the mount to get to them. After that I'll pull the pan to get to the main.

 

[seldomseencj7]

this is my first jeep that ive owned. Is the rear main seal a common problem?

 

[Tommy]

Please take the time to look and see if oil is leaking from the rear of the valve cover down through the bellhousing. This leak will look exactly like the one you described. The rear main seal is not a common problem that I know of. I had to loosen both motor mounts to get to the bolts you mentioned and to also slide the pan back past the oil pump. I didn't have to pull the motor but I jacked it up a few inches. Take your time, new seals are easy to ruin.

Tommy

 

[Casuall454]

As to removing the bolts on passenger side.... Can you get a floor jack with a block of wood between it and the harmonic balancer....lift enough to get pressure off the 3 motor mount bolts..... remove them.
Then lower the block about 3/4 inch so the oil pan bolts clear the motor mounts?

Just a thought?

 

[Rollbar]

NO! 9x out of 10 you will have to turn the crank to get the old seal/new seal in plus you might have to loosen some crank bolts to do this.

There is a spot w/a hole on the block on the passenger side, that's where I supported mine but I had a lift/tranny jack.