Fixing the rear main seal on FE
 

Can you replace the rear main seal without taking the engine out? I was hoping that the leak was just coming from the oil pan but not my luck. Put the car up on a lift and it is pretty obvious the oil was leaking from around the crank. Your suggestions on what to do would be appreciated.

Thanks
Ed

Ed,
I find that if you just drain the oil, it won't leak.
Steve

Ha! Ha! Ha! Real funny. I was actually thinking of adding synthetic oil & then draining it & not use any oil. The commercial had the car running for awhile. Maybe I should try that.**) I have also heard that FE's like to sweat but this is more like the pilot in that movie "Airplane" in how much he was sweating.

You CAN replace the rear main seal with the motor in the car...not terribly easy, but not terribly hard...it can be done.

This procedure explains how to do it. This procedure will work on all FE series Ford big block engines however, you may or may not have to raise the motor to remove the oil pan. Depends on application.

Hope this helps…….

http://www.squarebirds.org/rear_main_seal.htm

Wow! Thanks Timmy. That is exactly what I was looking for. It looks like a fun project!:JEKYLHYDE

Thanks
Ed

You're a glutten for punishment. I have done it on a small block and it does take some time. A bit messy too!

Good luck.

Clois

Glad I could help.

Mine is leaking too. I was using that procedure and got as far as dropping the oil pan. To my horror I found two chunks of a piston skit in the bottom of the pan. Seems the # 3 piston didn’t like having a skirt on it. I decided not go any further at that point. Put the pan back on and started putting together what I wanted to do for a rebuild.

I’m scheduled to do the rebuild starting the middle of December. Christmas should be fun.

Let us know how it turns out......

Tim

Fel Pro makes a seal kit that is two peices (no rope)that could work for you. It comes as a seperate kit. The rear main cap is sealed with two strips that you expand inplace by driving a nail like rod in to each strip.But then again you have to get the pan off to get the mains loose.Sometimes short cuts aren't that short.Any other tasks that you may want to do when it's apart?Now would be the time.

Well I finished the replacement last night and it actually wasn't that bad of a job. It took about 2 hours to get the car up on jack stands and everything taken apart. Another 3 to put it all back together. There was plenty of room under the Kirkham to drop the oil pan. I had to turn over the engine to get the crank throws up out of the way. The old seal was the same kind as the new so I didn't need the "Sneaky Pete" tool. I just used a small punch to get it out some and then used pliers to get it out the rest of the way.

After looking at the old seal I could tell why it was leaking but I didn't know how. The back side of the seal that sits in the main was worn down and I didn't know how it got worn down until I put the new one in. You have to be very careful when putting the seal that goes above the crank. When you start to put it in it gets very tight and the edge or I should say the outside will rub against the corner of the hole taking the edge off as you put it in. The edge started to come off & I let up a little & moved it around until it was easy to go back in. Also make sure the seal is sticking out 3/8" out on one side so it's not flat with the main. That will prevent another leak. That also could have been where mine was leaking as well.

The hardest part was to put the main back in. It was a very tight fit and the side strips did not want to go up with the main. What I figured out was to get the main just started and then push the strips up so 3/4 of each on was sticking out the top. They went in easier then.

All is put back together but it was too late to test it out. That will be tonight. Keep your fingers crossed.

Thanks for all of your help!

Ed

...you know I'm geting ready to re-assemble my block. I think I will pay real close attention to the rear main seal. :D

Ed...how big was the leak?

Well it is still leaking:CRY: I brought it up to operating temps and just a few drops but I noticed that after I shut it down it really started to leak. Enough oil to make a 4" spot on the floor! Before it seemed that it was leaking while the engine was running and much more. It lost about a quart of oil in 400 miles.

Any ideas?

My rear seal has never leaked and I noticed when I pulled everything apart last week that my builder had used clear silicone in the sides of the rear main. I actually had to use a razor blade to cut the silicone away from the sides of the main bearing cap. Did you at least use small dabs of silicone on the gasket where the top gasket meets the bottom gasket?

Clois

Not too much on the sides because I couldn't get the main in very easily. I did put some on the inside of the block to seal up the crack between the block & Main. Also put a dab on the top of the main.

Thanks
Ed

Ed, FWIW, I was SURE I had a rear main leak on my FE, but the primary source turned out to be something else. Over time, I found leaks coming from (in no particular order) the front plug (on side oilers), the rear intake-to-block seal (particularly at the outside corners where the head, block and intake all come together), and valve covers. Would it be worth wiping the motor down real good with brake cleaner and putting in some flourescent tracer dye in the oil? That was helpful for me on a particularly pesky leak...obviously not necessary if you're positive it is the rear main. I hate to say it, but it could be that the repair was faulty...it has happened to me on FE rear mains, they're not the easiest seal to fix.

Ed,
It's not fun but you should consider the rear oil galley pipe plugs [on each side of the cam plug] or possibly the pop - in cam plug. These have been known to sweat over time.
Unfortunately, trans, bellhousing and rear block plate have to go to check this.
Good luck,

Well this really sucks!! Tonight I replaced the seal again and I learned from the first time that I should not have used RTV between the main & the block at all but it still leaked! WTF? WTF? What else can I check? It seemed that when I put the seal in that goes above the crank, it was pretty easy to go in. Could the crank be worn down enough that the seal is too big? It almost seems impossible that the leak could be coming from the pan either.

Any suggestions?

Thanks
Ed

Ed,


Give George Anderson at Gessford a call, he might help you. I have a small leak as well, but it appears to be coming from valley on the back side of the block where the intake monts to the block. I'm using a dye to to confirm the origin.

Chris

A few questions about the crank that's in there. Your running a 410 so i'm guessing a 390 block with 3.98 428 crank? Double the oil hatch marks on the rear of the crank. These are the //////// marks on the rear of the crank and keep the oil from running outside the seal and south from there. Not sure if your engine was running fine before and just started to leak or a rebuild. If it's a rebuild check the crank as they might have been machined or smoothed. Also check for anything that could catch and tear the seal. Either one of these would help oil out of the block as well. I also second the plugs by the rear cam plug. Some early blocks used the press in plugs as well and should be replaced by threaded. Also good teflon sealer on the threads. This will simulate a rear main leak and is something to think about. The bad part being the engine needs to be raised at least if not taken out of the car to replace them. Are you using the rope or neoprene lip seal? G.