Uphill oil leak

Ford knew there was a problem with oil leaking out the rear main when going up hill. There was a modification done to AA trucks because they were the ones that were doing most of the uphill work and leaking. I believe it is in the service bulletins how to fix that.
 
John,

Thank you for the information. I have read that passage in the service bulletins and I believe there is something else causing this leak because the leak occurred even when the oil level in the pan was reduced to just above the LOW mark.

Bob
 
In the service bulletins (page 306) it says that the new rear main drain pipe with a check ball for trucks that are tipped at angles over 16 degrees (lifted by the ft end to dump the load)

My car had a repro dipstick, it had the marks over 1/4 " higher than the original, and the bend on the short tang was rounded preventing it from seating fully, this added another 1/4" to the oil level

The owners book says the level is full if it is up to the "F", I take this to mean that the level should be below the bottom of the F

My brothers driveway is about 10 degrees, my car leaves no drip on his driveway if the oil level is midway between the L &F either running, or shut off.
 
From my calculation at an angle of 16 degrees the oil level at the back of the engine will be around 1/2 inch below the bottom of the block. This would then allow the oil to pour downwards through the rear main bearing. So a check valve would make sense in that situation. But I am fairly sure my problem is not due to that situation.


Bob
 
Bob Johnson said:
From my calculation at an angle of 16 degrees the oil level at the back of the engine will be around 1/2 inch below the bottom of the block. This would then allow the oil to pour downwards through the rear main bearing. So a check valve would make sense in that situation. But I am fairly sure my problem is not due to that situation.


Bob
Click to expand...
Ever heard of siphoning?
 
Re: Video of leak

When you said you had an oil leak I didn't know you meant YOU HAVE AN OIL LEAK.
Does it happen to have an early valve cover on it that raises the oil level quite a bit
in the valve chamber?
Does the rear thrust surfaces meet together at the cap?
I have a oil leak I am getting ready to dive into also, its not anywhere as bad as yours.
I'm going to keep an eye on this site to see your progress.
Are you the Bob Johnson from Marin?

Dodge Riedy
 
Dodge,

Not an early valve cover, but I do not think that makes much difference in this case. I have tried the thrust surfaces square to each other which gives a 0.008" thrust. I have also tried offsetting the cap to decrease the thrust to 0.005". Both had the same result.

Yep Dodge that is me.

Bob
 
dip stick
 

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Bob Johnson,

The last time that I observed a rear main leak as profound as what you are showing in your video, was due to the rear main babbitt separating from the cap and was moving back and forth when the clutch was depressed.

There was a transverse crack at the rear portion and another at the front, the oil was travelling through the cracks, going between the babbit and the cap and exiting through the rear.

Darryl in Fairbanks
 
Darryl,

Thank you for the information. It got me thinking. When I looked at the rear main cap (removed from the block) I did notice that the babbitt job had issues. I could see some small voids between the babbitt and the cap along the top of the cap where the shims are. Maybe the oil is going down the void and exiting out the behind the thrust surface?

Bob
 
Marshall V. Daut said:
Keep the oil level halfway BETWEEN the "L" and "F" marks on the dipstick. The difference between that and at "F" is less than 1/2 quart, so you will not be starving the engine for oil. When the oil is at "F" on level ground, that's too high and when the car is parked on a steep incline with the nose of the car pointing uphill, the extra oil will be too much for the rear main "seal" (it's not a seal!) to hold back. So, the excess oil drips out. This is not a problem in Nebraska or Kansas, but it can play havoc in steep hills/mountain areas of our country. Try draining a little oil until you reach the halfway mark and then see if the leaking continues. There will still be residual oil back there from earlier steep incline parking, so don't expect the problem to go away immediately.
Marshall
Click to expand...

Interesting, as a newbie Model A owner of 5 months, I changed my oil and naturally filled the car up to the "F" level. I noticed about a week or so later a stream of oil coming out the back of the pan.... My Driveway is about 10°... (on it's own after I turned the car off a 2-3 hours later the oil was.... just about 1/2 between L and F and that's where I keep it.. So far not more oil leaks (BIG STREAMS )... and that was in April..
 
Just wondering, what type of oil filler cap is on the engine. Has someone stuffed something in the cap to slow the blow by? Are the baffles bent, causing pressure in the crankcase?
 
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