98regency

Hey everyone

I have the problem, that my engine is leaking. I think it's the oil pan and the upper main bearing seal. My question is, how to change the oil seal. Do I have to change the whole seal or can I repair it? Has anybody ever made this?

On the picture you can see which seal I mean.



-98regency-

don71

That rear main seal is not easy. Most of us will tell you to pull the engine, though it can be done in the car carefully. The reason is, the oil pan needs to come off. You can kill both of these leaks at the same time.

You can remove one of the engine mount bolts and lift it a little to get the pan off. Remember the crank shaft throws need to be in the right position to get the pan off.

This might also mean you need to remove the distributor as well to gain that extra inch. Or maybe not. Just keep in mind you might have to remove/or loosen some other things.

Like I said its not easy for some.

pogo69

I agree...this is a real pain to do and the chance of a re leak after you install it (if you are using a rope repair seal) can occur. if you have the slightest idea other seals need replacing or anything internal like a timing chain you might as well pull the engine. like what was already said you need to lower the pan so you have to lift the engine up anyway

98regency

Yes, I'm aware of the oil pan removing. Below you can see the repair description of the service manual. As I understand it is the only way to fix the leaking with engine on car. The only thing I don't understand is marked red. Add 1/16". What does this mean? And it's not sure to fix the leaking with this repair. Perhaps the seal could be damaged. Don't know.

98regency

I have to change the oil pan seal anyway. It leaks too much.
The problem is I don't have the right tool to pull the engine up. I have to improvise something.

m371961

Before I would do it I would clean everything then tighten the pan bolts. I also would put up with the leak of a main seal unless it was so bad the oil was leaking severely as I drove it down the road. Nasty and hard job with engine in car.
Also research replacing with a lip seal instead of packing.
Old cars don't leak oil, they ooze character.

pogo69

if you want to use a rope as opposed to a neoprene Ford seal then your adding a 1/16 to an 1/8 longer on the rope to install it then trim flush , add a sealant (aviation sealant/rtv)

MDchanic

The additional 1/16" on each half of the rope seal is to ensure that the seal crushes properly, but, as has been said, you're much better off with a neoprene seal than a rope seal (which is 19th century technology).

Remember that to replace the seal, you have to drop the crankshaft down slightly to take pressure off of the upper half of the seal, which means separating the engine and transmission, disconnecting the crank from the torque converter, and loosening all of the main bearing caps.
By the time you have done all of this, you might as well have just removed the engine and spared yourself the oil in your eyes.

- Eric

Sugar Bear

Have used this method several times MANY years ago and it worked well then; but, would not recommend it now for two reasons. First, there are now neoprene seals available and second the old upper seal that is being "packed" has seen too many years of service.

This method left the old upper seal in place and it was packed tighter by driving the tip of the tool into the groove in the block on both sides. If the old upper seal was compacted 1/4" you would cut a piece 1/16" longer or 5/16" from the old seal in the main cap and pack it into the upper groove. The lower seal was then replaced with a new rope seal. At the end of the day there was a new seal in the bottom half and three pieces of an old one in the upper; but it worked!

olds 307 and 403

Tough to get the old one out but might be worth it. I changed mine with crank in place but the motor out. I used the AMC 6 cylinder rubber rear main but the Ford 292 rubber seal also fits.

rustyroger

If you don't have access to an engine hoist, and the oil leak isn't ugly or illegal, wait until you can get use of one.
It's a messy job if you leave the engine in place, to do the job properly you will have to lift the crankshaft out of the upper main bearings. You might as well fit a neoprene seal, and with the engine out of the car changing the oil pan gasket will be much easier too.

There is always the danger that you will decide to replace the timing chain and sprockets, bearings, oil pump, before you know it you have a block and crankshaft in the machine shop and a complete rebuild on your hands.

Roger.

98regency

Thanks for the answers!

I have to change the seals with or without the engine out.
Here in my country we have a very strict "vehicle inspection office". Every two years our cars have to go to this inspection and if they see just one drop of oil on the pan or engine --> failed and I have four weeks to fix it^^

Which neoprene seal fits with my engine? Or which one is the best?^^

pogo69

what engine do you have....the ford 460 seal works on the olds 455

98regency

I have the 307 VIN Y engine

olds 307 and 403

The 292 Ford Y block V8 and AMC 258 straight 6 neoprene rubber seals fit. You need to trim a couple of side pieces on the AMC seal, very easy. I have installed the AMC seal in a 350 and 403. You still may have slight seepage even after changing the seal. You need to lube the seal to install them, tight fit. The groove goes to the inside and put RTV where the two seals join. Even if there is seepage bring brake clean and spray down just before you go in the inspection station.

MDchanic

Here is more information.

- Eric