Rear Main Seal: Pre-Lubricate or install dry?

Messages
55
Location
ON
Thread starter
Finally got a new rear main seal for my Celica, since I originally was shipped the wrong part and had to replace. Ended up getting a Fel-Pro seal. Just wondering, since I can't seem to find it anywhere in the service manual, should the rear main seal be pre-lubricated before installing?
 
Messages
718
Location
New York
Read the manual that comes with the part. The service manual cannot give you guidance on this. There are some rear main seals that are not meant to be lubricated (the PTFE ones for example), lubricating those will result in early failure, you do not want to repeat this job. https://webcache.googleusercontent.com/search?q=cache:Cka0FzgFOTEJ:https://www.fmmotorparts.com/garage-gurus/tech-tips/ptfe-rear-main-seal-installation-tip.html+&cd=17&hl=en&ct=clnk&gl=us Also here's a PDF from VR that has a bunch of steps for their PTFE seals (that are usually the same steps for all PTFE). Note that you don't lubricate and you remove them from their tube/holder only before installation. https://www.victorreinz.com/functio...ebe7443f55a7e3a00e1002a4a10797e0cc4d0099
Quote
Damaged PTFE Sealing Lip The most frequent cause for failure is damage to the PTFE sealing lip during assembly. If the seal is installed without the help of a sleeve or special tool, and is shifted or even turned inside out, reliable sealing will hardly be possible. Similarly, the use of oil or grease - as with classical oil sealing rings - will result in total failure of the PTFE oil seal immediately after installation.
 
Messages
55
Location
ON
Thread starter
So I installed it with some motor oil to help it slip in, seemed okay. Fel-Pro didn't provide any instructions at all. What I can say is it definitely looks like Viton or similar, not PTFE
 
Messages
11,638
Location
North Carolina
I always lube them. My assembly lube for rings, cylinder walls and seals like this is a mix of motor oil sometimes hedo and 50% sheaffers #132.
 
Messages
1,130
Location
California
I never install dry seals. They always get grease, oil, silicone (for o-rings), or some other kind of lubricant.
 
Messages
452
Location
Canada
Old school rubber looking (Viton/EPDM) seals are designed to lose a very small amount of oil over time. It definitely helps to add some lube to these when installing. PTFE seals should only be installed dry. When in operation, these seals self lubricate and wear themselves in to accommodate the minor imperfections of the associated sealing surface.
 
Messages
6,667
Location
California
Read the service manual and any literature that comes with the part. I never installed a rear main, but Toyota does say use multi-purpose grease on the lip of the seal before installing. Some of the Fel-Pro ones are to be installed dry and not to be removed from the packaging sleeve which doubles as the sleeve to install the seal. You remove it once the seal is on the crankshaft.
 
Last edited:
Top