Engine rear main seal quesion

RCFlyguy · Post by **RCFlyguy** » Mon Jun 25, 2012 11:04 pm

When I assembled my engine earlier today, I put in a new rear main seal. It is a repro seal that came in the major engine overhaul seal/gasket kit that Pete Debela sells. I put the seal halves in and trimmed them to fit as per the manual. However, when I install the bearing cap and torque the main bolts, I get a bind. I know for a fact it isn't the main bearings because I tried it without the seal and it was smooth and free. With the seal in and torqued, it takes quite a bit of force to turn the crank over (I have to put a socket wrench on the pulley nut on the crank to do so). I've never done a major overhaul before and found this a bit odd. Is this common when installing a new seal? Will it wear in quickly/safely? I am concerned the starter will not have enough juice to turn it over as it is.

artificer · Post by **artificer** » Tue Jun 26, 2012 9:08 am

Known problem area. Don't ruin your good work.
Neoprene or rope seal?
Neither should be that tight....
Searching might help here & elsewhere.
Post pics of the seal you used, might help us help you.

Post by **wesk** » Tue Jun 26, 2012 10:44 am

The rope seal gets trimmed and the garlock type do not. Turning resistance should increase when before and after seal installation comparison's are made. There is not a published turning resistance torque number to rely on. If you are using a socket and 1/2" drive ratchet and using only your fore arm strength to turn it you will be ok. If you are putting your shoulder in it then there is an issue. Did you prelube the bearings and the seal?

RCFlyguy · Post by **RCFlyguy** » Tue Jun 26, 2012 12:58 pm

The seal was a molded rubber type. It had a metal insert molded in for stiffness. It looks exactly like the old one that I took out. The bearings were pre-lubed with engine assembly grease and the seal was pre-lubed with STP+oil. I'll go put a torque wrench on it later today and turn it just to get an approximate value (pistons are in now).

jam51m38cdn · Post by **jam51m38cdn** » Tue Jun 26, 2012 4:01 pm

There is a known problem with the rubber seal in the MD-Juan kit`s that are out there, no one will tell you about, that I experienced last year. Just like you, I had the same problem. You need to get a new victor rear main seal as the one`s in the kit were made out of spec. Replace the 2 part rubber seal and you`ll be good to go, and can then turn the crank by hand. Jim

artificer · Post by **artificer** » Tue Jun 26, 2012 4:46 pm

The steel backed neoprene seals are not meant to be trimmed....they are meant to form a perfect circle [just like an engine bearing] when in place & the cap is torqued down. Trim them & they will not be a perfect circle but egg shaped & will leak.

The bad seals included those marked victor were/are not limited to any particular brand kits & were/are in any number from various sources.

Your reseller should be consulted as there would not be one of them who is unaware of the issue/s.

Post by **wesk** » Wed Jun 27, 2012 8:43 am

RC,

There are two separate issues with the molded garlock type seals.

1-Many 1990 vintage production seals were dimensionally incorrect and overheated.

2-There were early and late crank seal surface dimensions. The molded Garlock type seals will not seal well on the early crankshafts.

Also many crank rebuilders fail to polish the seal journal of the crank when polishing the three main journals.

Review my photo album under "Rear Seals"
http://www.willysmjeeps.com/v2/modules. ... _album.php

RCFlyguy · Post by **RCFlyguy** » Thu Jun 28, 2012 10:35 am

Thanks for all the help on clearing up this situation. The seal I have looks like the molded seal in your album Wes. I guess I will start searching for a different replacement seal, preferably the rope seal. Thanks again.

Post by **wesk** » Thu Jun 28, 2012 5:35 pm

If you have an early crank and it's seal surface dimensions are not correct for the garlock type formed seal you have no choice except to use the rope seal.

Don't think that just because you have a F-134 in an M38A1 that you couldn't possibly have an early crank. The F134 was introduced in 1950 in the Jeepster so it is not uncommon for an M38A1 to have an F134 with an early rope seal crank.