Rear Main Seal

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wv model AA
Posts: 69
Joined: April 16th, 2013, 9:24 am
Body Type: Dump truck
Model Year: 1931
Location: Shepherdstown, WV

Rear Main Seal

Post by wv model AA » June 28th, 2017, 5:38 am

I have a friend who working on a Model A Car before getting ready to sell it.

He noticed when the car is running, its loosing oil. What are the reasons why the rear main seal leaks bad when running? Drips a little bit when the engine is turned off.

Suggestions?

Thanks for listening.
West Virginia Model AA

"Hold My Beer and Watch This..."

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1crosscut
Posts: 692
Joined: December 25th, 2010, 7:22 pm
Body Type: 82-A
Model Year: 1929
Location: Lincoln, NE

Re: Rear Main Seal

Post by 1crosscut » June 28th, 2017, 6:07 am

Several things could be contributing to it.

Oil level too high. Put it halfway between full and low on the dip stick.
Too much clearance in the rear main bearing or bearings shot.
Drain tube on rear main plugged or missing.
Oil filler cap plugged or pushed down too far creating back pressure inside the engine.
Worn rings and the blow by pushing oil out.
Gasket between flywheel housing and block missing or gone bad.

Others will probably chime in with other ideas.

Is this something that has just started or has it been going on for a while.
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Dave

Stakebed
Posts: 1035
Joined: June 14th, 2007, 7:29 pm
Body Type: Grainbox
Model Year: 1929
Location: Illinois

Re: Rear Main Seal

Post by Stakebed » June 28th, 2017, 6:36 am

isnt there also a slinger ring? or is that only on the front....

if its all of a sudden the return tube has a possibility to fall off - most people make a quick tack weld to hold it in place.

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wv model AA
Posts: 69
Joined: April 16th, 2013, 9:24 am
Body Type: Dump truck
Model Year: 1931
Location: Shepherdstown, WV

Re: Rear Main Seal

Post by wv model AA » June 28th, 2017, 6:43 am

Basically, my friend is trying to help an elder to sell an Model A and they discovered it has been leaking oil.

It appears likely with the severity, I recommended of pulling the oil pan off and starting investigating from there before deciding of pulling the engine out.
West Virginia Model AA

"Hold My Beer and Watch This..."

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1crosscut
Posts: 692
Joined: December 25th, 2010, 7:22 pm
Body Type: 82-A
Model Year: 1929
Location: Lincoln, NE

Re: Rear Main Seal

Post by 1crosscut » June 28th, 2017, 9:37 am

Good plan. That way the seller and the buyer can make an informed decision.
------------
Dave

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