Rear main seal

[MikeKC130J]

Ok I have a freshly built 351W. 100 miles my rear main seal broke. How difficult is it to replace the 2 pc seal? Can I replace it while it's still in the bronco?

 

[Timmy390]

Never done it but yes, a 2 pc seal can be replaced without pulling the engine.

You need to drain the oil, drop the pan, take the crank bearing cap off on the rear (maybe looses all of them), drive or pull out the upper and lower seal, then reinstall the upper and lower parts of the seal. Torque everything back down and refill with oil.

I'm sure there are a few steps of things I left out but that's it in a nutshell.

Sure it's a rear main? I pulled my engine to replace the 1 pc rear main only to find it was the oil pan gasket. leaking. Could be the rear of the intake too or even the gallery plugs in the back of he block.

Did you put some lube on the seal when you installed it? On my 1 pc seal, I use some grease on the lip on install. Seems to work. Installing dry can cause a quick failure.

Tim

 

[DJs74]

And, when you install the new 2 piece seal, make sure the joint between the inner and outer are offset some from the main cap to block joint. you need approx. 1/8" to 1/4" of the seal protruding on one side which will put the other end recessed. The goal is to not line up all the joint lines between the seal and the block/cap. Use a dab of RTV at the two end joints of the main seal... not gobs, just enough so they adhere to each other producing a 360° seal.

One last thing, make sure you install the lip of the seal in the correct direction - toward the front / toward the inside of the engine - not toward the transmission

DJs74

 

[hucklburry rev2]

i'm about to replace one, but the engine is out. For the 2 piece I decided on a Fel Pro 2901, its made of some magical compound that makes it cost more, I got mine off amazon, it had some good reviews from some forums so I went with that, as spending more on it made me feel like I was buying a premium seal so I might not have to do it again once the engine is in the Bronco. You can get neoprene 1 pc also I think, and I haven't installed it or run it yet.

 

[blubuckaroo]

Ok I have a freshly built 351W. 100 miles my rear main seal broke. How difficult is it to replace the 2 pc seal? Can I replace it while it's still in the bronco?

Have you got this book?
If you own one of these old Fords, you need one.
It covers the process completely.
https://www.amazon.com/How-Rebuild-...6&sr=8-1&keywords=rebuilding+small+block+ford

If you follow the threads here, there are a lot of failed attempts to replace that seal.
I've never had one of my replacements fail.
Get the book!

 

[69Gumbi]

There is a pretty good thread titled. 2nd try rear main seal. It was a big help when I did mine I also added my detailed procedure I used. It certainly can be done in car it is not a lot of fun good luck.

 

[Juiceman]

Someone in one of the threads gave me some good advice to check to see if it leaking when driving or while parked. I thought my rear main seal was leaking as well. Ended up replacing the oil pan gasket and problem solved.