Seal replacement

[ezcurra]

Hello,

I just replaced the front and rear main seals on my 4BT. I lubed the seals before installation and I've just been told that they are supposed to be dry. Will this film of oil cause the seals to fail?

Thanks,

Mikel

 

[JFaughn]

In over 25 yrs of repair , I've have been putting seals in with lube , any trans shop that does not want comebacks buys a tube of lube just for that reason .
You may not want to go back to that place again .

 

[rbattelle]

Amen to what John said. I've been taught (by education and by experience) that you never install a seal without lubricating it.

Ryan

 

[ezcurra]

I've been told it's the Cummins manual that says they have to be dry. Apparently the seals have some sort of teflon coating that needs to bond with the crank seal surface.

Thanks.

 

[CumminsPower98]

This is correct. The Cummins front and rear mains go in DRY so that the Teflon heats up and transfers some to the metal surfaces creating a good seal. These are not a standard rubber seal, which must be lubed.



I have no idea what will happen to yours as I have never lubed one. I have installed many of them dry as directed and they work very well.

I've been told it's the Cummins manual that says they have to be dry. Apparently the seals have some sort of teflon coating that needs to bond with the crank seal surface.

Thanks.

 

[ezcurra]

The engine is still off the truck and it wouldn't be overly laborious to remove the seals and dry everything with alcohol. Would this damage the teflon coating?

Thanks,

Mikel

 

[JFaughn]

Thats good to know .

 

[CumminsPower98]

I couldn't tell you, maybe someone would know. Soap and water might be better but might not clean them as well either so I don't know.

The engine is still off the truck and it wouldn't be overly laborious to remove the seals and dry everything with alcohol. Would this damage the teflon coating?

Thanks,

Mikel

 

[rbattelle]

Teflon is pretty resistant to all types of chemicals. I don't think alcohol would hurt it at all.

What I'll never understand is how we're expected to believe that Teflon, a self-lubricating substance to which almost nothing will stick, is going to stick to the metal surfaces! Not to mention the maximum operating temperature of Teflon is 500°F (it melts at 648°F).

So we're supposed to believe that your front and rear crankshaft ends are going to heat up to more than 648°F and a substance which won't stick to anything is going to stick to them?

Sounds pretty iffy to me. Unless maybe the Teflon is contained in a binder with a lower melting temperature and an adhesive quality? But then wouldn't the adhesiveness of the binder prevent any possibility of a seal?

[Cumminspower98, I'm not doubting you at all! I'm sure that's what Cummins says to do, I'm just questioning how realistic it is. Please don't think I'm saying you don't know what you're talking about - I believe your experience wholeheartedly. The only question is - if you lubed one, would it seal as well?]

Ryan

 

[hotram03]

I've installed several seals, all dry and wearing clean rubber gloves making sure as to no oil, and using the plastic install sleeve its a sinch. I would clean the crank with Acetone, its the only thing that doesn't leave an oil residue, lacquer thinner leaves an oil residue, extremely minimal, but still there.

 

[CumminsPower98]

I really don't know and am no expert. I'm just going by what I have read here and have never installed one with oil so no idea what would happen.

 

[RHARVEY]

I too see where Cummins manual says to put the seal in dry. . but my question how do you get it over the crank?

I followed the instructions and used the guide sleeve over the crank but it wont go. What is the trick or did Cummins send me the wrong seal? Is there a difference between a 12v and 24v crank seal?



Thanks

Rick