Rear Main Seal Replacement
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5th Wheeling
Joined: Dec 2025
Posts: 27
Likes: 7
Rear Main Seal Replacement
So, while needing to replace the water pump on my 1987 F-250 with the 460 engine. I think it is a good idea to also reseal the timing chain cover as well. But while already that deep in, I would like to finally fix the rear main seal leak it's had for years, since you already have the oil pan open on the front. might as well drop the whole pan, right? The thing is, all modern BMWs I have worked with have a one-piece seal, and you don't have to remove the rear main either. So I am trying to find others who have the knowledge about this kind of job. It seems people replace a bearing while doing so. Also, there seems to be a crush depth with the seals themselves, as well as an offset alignment. Any information about this procedure would be helpful. I know I would need to check the clearance of the new bearing as well. Also, I did post this in the brick nose section, but just realized there is a big block section as well.
Hotshot
Joined: Jul 2020
Posts: 10,410
Likes: 2,611
From: Near Salt Lake City
Watch a few videos
The engine goes up and the pan comes off
Lift engine with harmonic damper until the truck frame starts to lift and block the engine there with blocks or sockets
Bitchy job, pays about 8 hours at a dealer for the tech
I've done it several times as a motor man at the dealer
Almost everybody gets thrown to the wolves as a motor man at some point at the dealer
"Come bad or stay home" was the motto
You do the same
Glue the pan gasket to the block when you go back together
Have the front cover on there so you can properly squish the front pan end seal when you bolt the pan up
There are a few more tricks concerning the gasket, so you don't have to do it twice
Best of luck
The engine goes up and the pan comes off
Lift engine with harmonic damper until the truck frame starts to lift and block the engine there with blocks or sockets
Bitchy job, pays about 8 hours at a dealer for the tech
I've done it several times as a motor man at the dealer
Almost everybody gets thrown to the wolves as a motor man at some point at the dealer
"Come bad or stay home" was the motto
You do the same
Glue the pan gasket to the block when you go back together
Have the front cover on there so you can properly squish the front pan end seal when you bolt the pan up
There are a few more tricks concerning the gasket, so you don't have to do it twice
Best of luck
Thread Starter
|
5th Wheeling
Joined: Dec 2025
Posts: 27
Likes: 7
Watch a few videos
The engine goes up and the pan comes off
Lift engine with harmonic damper until the truck frame starts to lift and block the engine there with blocks or sockets
Bitchy job, pays about 8 hours at a dealer for the tech
I've done it several times as a motor man at the dealer
Almost everybody gets thrown to the wolves as a motor man at some point at the dealer
"Come bad or stay home" was the motto
You do the same
Glue the pan gasket to the block when you go back together
Have the front cover on there so you can properly squish the front pan end seal when you bolt the pan up
There are a few more tricks concerning the gasket, so you don't have to do it twice
Best of luck
The engine goes up and the pan comes off
Lift engine with harmonic damper until the truck frame starts to lift and block the engine there with blocks or sockets
Bitchy job, pays about 8 hours at a dealer for the tech
I've done it several times as a motor man at the dealer
Almost everybody gets thrown to the wolves as a motor man at some point at the dealer
"Come bad or stay home" was the motto
You do the same
Glue the pan gasket to the block when you go back together
Have the front cover on there so you can properly squish the front pan end seal when you bolt the pan up
There are a few more tricks concerning the gasket, so you don't have to do it twice
Best of luck
The thing I am wondering about is the rear bearing on the rear main cap. Some people think that you should replace the bearing while the cap is off. Also, it's not like you can just buy the one rear main cap bearing usually. But that seems odd to me, I would feel more like that would be something for when you do all the bearing with an engine-out job. Also, I have seen people get the pan clearance by lifting the transmission. But lifting by the front damper is what you used to see more working on these, it seems. I would be doing the water pump and timing chain cover at the same time. As for the gasket, on BMWs I usually just zip tie 2 corners of the gasket through 2 of the bolt holes on the pan, then cut them off once I have all the other pan bolts in but not snugged down. But would you recommend then a bead of RTV for these instead?
Hotshot
Joined: Jul 2020
Posts: 10,410
Likes: 2,611
From: Near Salt Lake City
You will be inspecting the lower half of the rear main bearing once you get the rear maincap off
Right, we used to replace the bearings if down to the babbit (brass)
A rear main bearing with excessive clearance can ruin your new rear main seal
Your gasket will need to be glued to the block, not the oil pan, it will leak if you do it the other way around, and the gasket will not make the trip
This pan gasket setup has the end seals that go "over the gasket tabs"
Wait until you see how hard it is to get the pan out, and how the gasket will not make it back in there in one piece
I do flat pan gaskets like you mention
Ford FE motors for instance, you can do it like that, because the pan gasket surface is flat and so is the gasket
Right, we used to replace the bearings if down to the babbit (brass)
A rear main bearing with excessive clearance can ruin your new rear main seal
Your gasket will need to be glued to the block, not the oil pan, it will leak if you do it the other way around, and the gasket will not make the trip
This pan gasket setup has the end seals that go "over the gasket tabs"
Wait until you see how hard it is to get the pan out, and how the gasket will not make it back in there in one piece
I do flat pan gaskets like you mention
Ford FE motors for instance, you can do it like that, because the pan gasket surface is flat and so is the gasket
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