Engine Questions...Preference of rear main crank seal/sleeve kit and clutch?

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New Member
Dec 15, 2021
I just purchased a 1 piece rear main seal today as I have had a leak with lower pan and rear main since i purchased the cxar 4 years ago, just havent had time to fix until now . Anyhow with the instruction ( Fel Pro BS 40644 ) With the plastic sleave and in the instructions a little piece of paper states that Ford Possibly drilled to far when manufacturing and Possible oil leaks may occur , anyhow I see a few have mentioned this however just thought Id post a pic and see if anyone else ha noticed the leaks from the bolts themselves and or not the old seal itself ?? Anyhow Paper States exactly Flywheel Bolts Reinstall Flywheel To crankshaft Note: On Some engines that use a 1 piece rear main bearing Seal a condition may exist where the bolt holes in Crank shaft rear flange have been drilled to deep by the manufacturer. This can result in seepage which may be misdiagnosed as coming from oil pan or rear main seal. To prevent seepage, Coat bolt threads with thread locking sealer, Torque securely to oem specifications. Anyhow Im about to give it a shot myself, Thanks for Letting me join Stangnet by the way !


Put lubricant all over the balls
Mod Dude
Feb 18, 2001
Some cranks have the bolt holes drilled all the way through. Some don’t.

If you buy new Ford bolts, they come with sealant on the threads. Most folks reuse flywheel bolts so new sealant needs to be applied or your sometimes end up with leaks from the threads.

Some folks loctite the threads, some use sealant. I can’t recall what I used.


10 Year Member
Nov 12, 2003
Santa Rosa, CA.
I just did this last week although my motor is out of the car. I installed the Fel-Pro crank sleeve.....
Fel-Pro 16250 crankshaft repair sleeve

RMS repair sleeve2.JPG

Then I used Ford Racing's one piece rear main seal.........
Ford Racing rear main seal

As far as the flywheel bolts, I used a bit of this............
Permatex thread sealant

Hopefully, I won't have any RMS leakage problems. Time will tell!