QuestionQUESTION: I have a 1989 Ford 250 that has a major leak at the rear engine seal. When replacing the seal, I would also like to replace the main bearings to assure that seal doesn't get beat out again. What is involved in replacing the main bearings? Is it possible to replace the mains without pulling the engine?
ANSWER: Hello
Which engine do you have?
The 300, 302 have 1 peice seals which are replaceble with transmission pulled back. The 460 requires oil pan removale.
If it is a 460, then i would remove just the end cap and inspect the bearing, if it is worn to the copper layer and no deep gouges, then replace the seal only.
Bearings will not cause oil leaks until they get very bad, then you would hear them.
Inspect the area on the crank which the seal contacts, if the wear is deep enough to catch your fingernail on, then a speedy sleeve is recommended.
other areas that can attribute to rear seal leak are: lack of regular maintenace, plugged PCV system and heat.
With everytyhing good, you should get another 20 years out of the new seal.\
To replace the bearings, you would need to remove the water pump and timing cover and timing chain to be able to drop the crank enough.
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QUESTION: I apologize for not stating the engine. I don't know that it will be different, but the engine is a 351 Cleveland. Which procedure works for that engine?
I have always understood that worn main bearings caused the rear seal to go bad. The truck does however carry good oil pressure even at idle. It has 140,000 miles on it.
AnswerHi again.
Your engine should be a 5.8L 351 W (windsor) as they stopped making the Cleavland and Michigan 351's in the late 70's
Either way, it is a 2 piece seal and requires oil pan and transmission removal (about5-6 hours shop time), After you remove the rear main bearing cap you need to be very careful not to scratch the exposed surface of the crankshaft.
Using a small pin punch should allow yo to break the upper seal half free and rotate it out.
