Rear Main Seal Question

[drose5432]

I bought my 68 m715 to a mechanic after noticing an oil leak. I was told by two different guys that it was the rear main seal. I called Memphis and was told they only sell military parts and if my truck was a civilian model, they don't carry parts.

2 questions;

1) My truck was owned by a FD, so I am assuming it is civilian model, although I am not 100% sure. Any way to find out?

2) Since I ordered the seal from memphis, the mechanic said it was not the right size (making me believe it was in fact a civilian model). Anyone know where I can get a rear main seal for a civilian model?

Thanks

[Beltfed Only]

Do you have any pix of your truck to help with identification?

[drose5432]

I am trying to figure out how to post a pic. Can I add it as an attachment if I have a picture saved?

Thanks

[Kaiserjeeps]

They are stubborn. I replaced mine twice and it still weeps a bit. If your mechanic replaces it and it seals, you have a good mechanic. Most seals of that vintage seem to leak some. Good luck and welcome.

[brute4c]

If the motor is a 230:

Military motors have the motor mounts bolted to the side of the block several inches behind the timing cover, very easy to check on the passengers side.

Civilian motors have the motor mounts at the very front on the lower outer edges of a steel shim plate that is sandwiched between the timing cover and the front of the block...they are not bolted to the block itself.

If it is an M715, it IS a military truck...though someone could have change the motor out...unlikely as the mount are so different but I know of at least 1 truck that the owner did the swap with.

All M715's came factory with the military motor.

[syzygy]

The fact that it was owned by an FD is very common -- after their military service many were given to local FDs as a "permanent loan". Many were titled to the FD with a chattel lien stating the vehicle was owned by the US Gov't, but when the FD's were done with them, they gov't obviously didn't want them back so they end up with people like us who appreciate them

[rboltz]

Since I ordered the seal from memphis, the mechanic said it was not the right size (making me believe it was in fact a civilian model). Anyone know where I can get a rear main seal for a civilian model?

Thanks

The seals are the same. I did this research some time ago. There is a thread called "Tornado block info" that has the info

Tornado block info

[cherylsm515]

most common problem of seal leaks is engine blow by. do a compression check and if cylinder are down or low replacing a seal wont do a thing. JMO

[amphi]

most common problem of seal leaks is engine blow by.

In conjunction with a bad or stuck PCV valve.