PTFE rear main seal installed NOT dry

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Originally Posted By: NoNameJoe

If you did the inner sealing lip, sorry hate to break it to you but it's likely to fail. PTFE seals are special because the sealing lip has PTFE that sort of melts or transfers a little PTFE on to what it's sealing against. This makes the sealing surfaces slide on each other smoothly.

Greasing the sealing lip prevents this from happening. There are peculiarities with PTFE seals vs other materials like neoprene or nitrile. For example PTFE seals usually come stretched with a ring you are only supposed to remove when installing (some of them say to use the ring to guide the seal into position). Then you're supposed to wait a few hours for the inner sealing lip to shrink a little. Then you start the engine and it transfers the PTFE over.


This is the correct answer. PTFE is a self lubrication seal which means some of the material transfers over to fill the voids from normal use. It's the same concept as the modern sealed ball joint/tie rod. If you get oil or grease on the shaft, the material transfer can never really occur effectively so now you'll have a leaky seal. As to how much oil you're going to be leaking, who knows. You are also supposed to use the included plastic guide when installing the seal and manually turn over the shaft a few times before operating normally.
 
I still use butter to cook eggs in PTFE coated frying pans, and my pans have never leaked. Basic logic says that I should have used butter on my rear main seal.

I can't believe that I overlooked that, especially since I used bread to drive out the pilot bearing. Bread and butter, duh!
 
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Originally Posted By: eyeofthetiger
I actually have not started the engine, yet. What if I stick a really long straw on a can of brake cleaner and poke it up there behind the flywheel?


That will not help, honestly either go in now and fix it or run it and hope for the best, if it leaks you have to go in anyway so run it and see. If it leaks look at it as a lesson learned and you will never make that mistake again.
 
Originally Posted By: Trav
Originally Posted By: eyeofthetiger
I actually have not started the engine, yet. What if I stick a really long straw on a can of brake cleaner and poke it up there behind the flywheel?


That will not help, honestly either go in now and fix it or run it and hope for the best, if it leaks you have to go in anyway so run it and see. If its leaks look at it as a lesson learned and you will never make that mistake again.


Yeah, I'm running it as is. I have to find out what happens.
 
Mystic Ducked sees two possible outcomes:-

(a) You run it and it leaks. The rest is silence.
(b) You run it and it doesn't leak, and you come back on here with "See? Told you so" and we say "Proves nothing, you just got lucky"

There. Saved us all some posting.
 
I'll bet this is a common occurrence. I'd just run it and see. Until the grease runs out, the PTFE won't rub to transfer. As the grease dissipates, the PTFE could then begin to transfer.

-m
 
Update: no leaks after over 3000 miles. Sold the truck a couple of months ago to a happy kid who was learning to drive stick. Will probably burn up the clutch, anyway.
grin.gif
 
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