69 Hurst

Looking for a little help guys. I have the engine out of the car to perform some detailing and chassis work. I want to change the rear main seal as I believe it is leaking. I've read different write-ups, some say you have to pull the crank, others say you do not. I trust this community more then a write up I find online so I'm looking for some expertise from any CO members that have done this, either with or without crank removal.

Thanks in advance
Dino

joe_padavano

I recently did this on a 350. I used a neoprene seal and I had to loosen all the main bearing caps and lift the crank enough to get the new upper half into place. It still wasn't pretty. Remove the crank and you MIGHTASWELL put in bearings.

69 Hurst

Exactly what I was thinking Joe! And a new timing chain.... The circle just gets bigger and bigger! Thanks for the reply.

69 Hurst

Has anyone used a rubber seal vs. the rope, and if so did it work out?

Thanks

joe_padavano

https://classicoldsmobile.com/forums...9-455-a-58494/
https://classicoldsmobile.com/forums...ptions-126413/
https://classicoldsmobile.com/forums...n-seal-125467/
https://classicoldsmobile.com/forums...n-seal-109484/
https://classicoldsmobile.com/forums...-350-a-106820/
https://classicoldsmobile.com/forums...n-seal-103047/

83hurstguy

I've done it in the car on both an Olds 307 and a Chevy 350. I had access to a lift both times. I couldn't imagine doing it without it. Trying to use a rope seal was a debacle, the neoprene seal was easier. These days, I just pull the engine...

69 Hurst

Thanks Joe,
This was extremely helpful. I'm off to pick up one of the 460 seals.

matt69olds

I have replaced the seal while the engine was in the car. If there are any other repair or maintenance work to be done to the engine I would definitely pull the engine. I did mine on the garage floor, it wasn’t that bad. I was also 25 years younger.


Remove the fan, distributor cap, motor mounts, and anything else that may cause clearance issues. Once the oil pan and oil pump is removed, remove the rear cap, loosen all the others to allow the crank to drop a little. You can remove the old seal and roll the new one in pretty easily. Install the new seal, re-torque the main caps. Make sure you offset the seal ends.