Rear Main Oil Leak Help!

R

RyanB

Member
Hello,

I had a bad rear main oil leak and I pintpointed it to a problem around the rear main bearing cap or return tube. This is a fresh rebuild of the engine so I was disappointed to see a steady stream of oil coming from the flywheel hole. I removed the pan and rear main bearing cap to clean and reinstall everything.

The question is that my return oil tube has a ball in the end that looks like it will restrict the oil return. It is an original tube I believe but I noticed the replacements don't have the ball. Should I remove the ball

I really don't want to do this all over again so any suggestions would be really appreciated.

Thanks!
 
AA's did have a check ball tube so when they went to unload grain and backed down the steep incline oil wouldnt run out all over the place with the engine off.

Not sure how to tell you to proceed haha.
 
That makes sense. It just seems like this might be my problem because it looks like it will not let much oil past it.
 
Please ignore my previous post. I intended to say , definitely remove the ball and assure that the tube is open and not restricted in any way.
 
Yea standard A's didnt have them so I would remove the ball and try that as well. The AA one i removed from mine looked like the standard tube with a short 1.5 extension braized to the outside with something like a 3/8" ball bearing inside with a cotter pin holding the ball from falling out in the oil pan. Looked very similar to a propane torch head haha.

Search the forums for pictures of oil grooves in the babbit - IF im remembering correctly they should not go all the way to the rear end of the engine or you will get excessive oil leakage...
 
Great advice. I will remove the ball and reinstall. I am sure that was my issue all along. A lot of work just to remove a little check ball.

Really appreciate the fact that I have a lifeline. For a newbie this can get frustrating quick.

Thanks!
 
While you are in the neighborhood, check the end play of the crank, and the clearance of the bearing, this has a lot to do with leaking rear mains.
 
RyanB said:
Hello,

I had a bad rear main oil leak and I pintpointed it to a problem around the rear main bearing cap or return tube. This is a fresh rebuild of the engine so I was disappointed to see a steady stream of oil coming from the flywheel hole. I removed the pan and rear main bearing cap to clean and reinstall everything.

The question is that my return oil tube has a ball in the end that looks like it will restrict the oil return. It is an original tube I believe but I noticed the replacements don't have the ball. Should I remove the ball

I really don't want to do this all over again so any suggestions would be really appreciated.

Thanks!
Click to expand...

Hey Ryan,
You do not state whether you are dealing with a truck engine(AA), with an A engine or a B engine ? Makes a difference for proper application, eh !

If not AA, there should NOT be any ball in drain tube.

If an A OR B engine the tube will be one of two sizes used by ford. Now make sure that you use the correct size drain tube for you application. Good luck :)
 
hardtimes said:
Hey Ryan,
You do not state whether you are dealing with a truck engine(AA), with an A engine or a B engine ? Makes a difference for proper application, eh !

If not AA, there should NOT be any ball in drain tube.

If an A OR B engine the tube will be one of two sizes used by ford. Now make sure that you use the correct size drain tube for you application. Good luck :)
Click to expand...

Yea the size thing is something to be aware of as well.

It was common practice in later years (40-50-60's etc) to swap out your car engine for an AA engine - identical except that check ball BUT aa's especially grain trucks like nowadays only get used a handful of times a year so they were low mile engines. Very common to put in a car that has a worn out engine so thats probably how you ended up with it. Does your engine serial # start with AA?
 
The engine is an A. We had a few engines that we were robbing parts from when we rebuilt this one so we might have grabbed the drain tube from the AA engine we have. Someone robbed parts from this engine 30 or 40 years ago. Really interesting to know. That is really why I love working on these cars, you learn something every time.

I got everything buttoned back up and took her for a drive and no leak so that must have been the issue.

Thanks for the help!
 
awesome good to hear, some people overfill the pan too, as long as the oil level is between F and L your good.
 
Also, excessive blow-by can pressurize the crankcase and push oil out the rear seal. It also comes out the breather and distributor hole, too!
 
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