M38Cdn Refurbishment

[rob love]

There were warnings about military vs civilian rear main seals, but as I recall the civilian ones were too tight. So tight in fact, they were causing rear bearing problems and leakage because of the amount of heat. Since then, some dealers have had proper rear main seals made up.
That warning aside, I have had it where the rear main seals take a little bit of time to set in. And they can be replaced while on the vehicle. I used to do them in about an hour, although it almost takes me that long to get onto the floor and back up again these days.

[Peter Phillips]

That's good to know, Rob...I'm really hoping this thing just needs to "run in" to seal up. You cracked me up about taking an hour to get down and up again, lol.

Got the carb kit from Brian today so that's on the list to do soonest.

[super dave]

I have rebuilt 3 jeep engines recently and I will only use the BEST made rear main seals as I have not had a single leak from any of them. The one engine I had to replace a rear seal as it was burnt up and took out the rear main bearing from being too tight of fit on the crank.

[Peter Phillips]

Originally Posted by super dave

I have rebuilt 3 jeep engines recently and I will only use the BEST made rear main seals as I have not had a single leak from any of them. The one engine I had to replace a rear seal as it was burnt up and took out the rear main bearing from being too tight of fit on the crank.

Hi Dave, can you elaborate on where you sourced your seals in the past? I went with neoprene vs rope which If I remember correctly I got from Brian.

[rob love]

The last engine I did was about 5 years back. The lack of availability of the rear main seal swayed me to putting in the rope seal. It leaked for a very short time, then sealed up.

John Bizal sells what is reputed to be the Best brand rear seal. The old part number for the military is reported as National 5585, but no longer made. The civilian seals that were a problem are reported as part number 800093.

[chris vickery]

Just have an engine back from rebuild. My engine builder threw away the rear main as supplied with the kit (from a MV parts dealer) because it was way too tight.
He opted for the old school rope seal for my build.

[Peter Phillips]

Originally Posted by rob love

The last engine I did was about 5 years back. The lack of availability of the rear main seal swayed me to putting in the rope seal. It leaked for a very short time, then sealed up.

John Bizal sells what is reputed to be the Best brand rear seal. The old part number for the military is reported as National 5585, but no longer made. The civilian seals that were a problem are reported as part number 800093.

OK sounds good, I guess time will tell what happens with this one. I'll definitely refrain from putting the tub on until I see what happens in case I need to pluck the motor out again.

[super dave]

As rob says Midwest Military usually carries them but are out at the moment but you can purchase them on ebay part number 3B71