Leaking rear main seal

[jack in san diego]

Help: I rebuilt my 59-A engine, put it all together,installed it in my '40 pickup, it runs really nice and smooth, lots of power etc. Now I have been driving it to check out all the bugs, etc. I drove it about 15 miles, and noticed the clutch was slipping. It is all new, clutch plate, pressure plate, etc. Well, I pulled the engine out and inside the transmission housing it is all really oily. The clutch plate is soaked with oil, and the flywheel area is all oiled upo. Obviously it is leaking oil out the rear really bad. I used the Felpro rear main gasket set when I put it all together. I am going to take the pan off now and see what is wrong? Is there a special after market seal that is made for these motors? I know a lot of people are going back to the flatheads. Any suggestions for me? Thanks in advance.

[Ken/Alabama]

It may not be the rear rope seal, it might be the cork strip that fits in the groove on the outside of the rear main cap . I always put a bead of RTV in the groove and before I put the pan on I put a fat bead of RTV on the cork where the pan mates to it and a bead in the corners .

[Karl Wolf]

There is a 1/4" pipe plug, goes under the top of the oil pump drive gear cover... My best guess is that it's missing... Second best guess: leak under the rear main cap, at the sides where the pan gasket meets it...
Karl

[jack in san diego]

Karl Wolf: Can you explain again just where this plug is located. Is it on the oil pump itself? Or is it somewhere in the engine? I think you may have solved my mystery if I can find where to look. Jack

[Jack E/NJ]

What's the oil pressure while driving?

Jack E/NJ

[jack in san diego]

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Karl Wolf: Thanks for the tip, but just where is this plug located? Is it on the oil pump itself? Or is it in the engine? If I can find it, I think you may have solved my problem. Jack

[jack in san diego]

Oil pressure drops down while driving, but is plenty on start up, like 50# as I rev up.

[Jack E/NJ]

Sounds like the plug's in there. Plug is between the flywheel and block under a coverplate near the top of the bellhousing. It also houses the gears connecting the pump to the camshaft.

Jack E/NJ

[Randy]

You sure it's not the front transmission seal?

[Jack E/NJ]

So Karl's 2nd best guess sounds like a good guess to me.

Jack E/NJ

[Walt Dupont--Me.]

Jack, when you remove the pan, carefully check that cork gasket on the outside of the rear main cap. I think that rear main line pipe plug is in or you wouldn't have 50# pressure BUT, it's posable the gasket behind that rear plate that covers those rear gears is not on right. The best rear main seals are made by the (BEST) brand gasket co. In fact there complete gasket set is the best out there. It's hard to replace the rear seal with the crank in but it can be done. Walt

[Karl Wolf]

To find the plug I spoke of, remove the flywheel... Toward the top, behind (forward) where the flywheel is, there is an irregular shaped plate held by 7 bolts... If you remove that, at the top of the place the plate covers is the rear end of the oil gallery tube... THIS should have a 1/4" pipe plug in it... The original has a flat-blade screw driver slot in it... You could put any 1/4" pipe plug in there, as long as long as the plug does not stick out above the surface...

This plug HAS to be there, the cover will go over it, but won't handle the oil pressure in the oil gallery...

Karl

[jack in san diego]

Thanks everybody. I do know that the cover behind the flywheel is there, but not sure if there is a gasket also, will check it when I pull it apart. Also, if the cork gasket is oiut or crimped or?, will find that when I pull the pan. I will post what I find when I pull the pan. Thanks again all! Jack

[Russ/40]

When you pull the pan, there should be a crease right in the middle of the cork seal running its full length. Who put the motor together?