Rear Main Seal Stop Leak

[PaulProe]

I ran this issue by a senior FelPro engineer at a PRI show a couple years ago. He was familiar with the FE oil seal, having worked on it early in his carrier.

He blamed the issue on a number of things:

• On the original models, it was an issue of machining and assembly tolerances. The big three were not know for high quality in the 60's
• Crankshafts: The original crankshaft has a spiral knurl in the general area of the rope seal. Its purpose was to channel any oil back to the pan. Some replica crankshafts had not included it in their design or had mis-manufactured it.
• Most importantly: The original seal was designed around the use of compressed asbestos to withstand the heat and forces of the seal. When asbestos was outlawed, the alternative materials do not perform to the level of the asbestos and do not properly meet the specs of the original design. The best you can hope for is one that only leaks 'a little bit'

His solution: Use the highest quality seal you can buy (guess which brand he felt that was ) and make sure the installation procedure was 'perfect' or the leak is guaranteed. If you've ever studied the process, you can't just slap it together and hope it will work. It takes a certain amount of experience and skill.

I run a Wagner PCV on my FE and found once it is set properly and my crankcase pressure is controlled, my leaks become tolerable.

Can they ever be stopped? I was informed by a fellow owner; "I was a salesman for Ford vehicles back in the day. Not saying FE's leaked, but we used to put a drip pan under the literature rack in the showroom" Remember, we're playing with 60's technology, expecting 2020 results.

Paul