460 Rear Main Seal

I have an oil leak that appears to be from the rear main seal and/or the oil pan gasket.  Would I be foolish to try and fix it without a lift?

Do everything you can to make sure it isn't from somewhere else, like the oil pressure switch on the back of the block.  That's because getting the pan off is not going to be easy.

I've pulled the pan on a 351W on a lift and it was no fun.  In fact, I vowed I'd never do it again.  Instead, I'd pull the engine.  But a 460 has to be much worse as there's even less room.

So I'd say that if I were to do it even my lift wouldn't sway me to do it in the truck.  I'd pull the engine.

I don't know anyone who has been able to pull the oil pan from a 4x4 460 in the truck.
So you're looking at pulling the engine to get the crank loose and a new seal in.

There was a guy from Colorado, back on FTE, that tried after he had been warned by many.
He said he would set the truck on fire in his driveway before he ever thought of attempting it again.

I actually thought about quoting him, Jim.  IIRC he said something like "If I ever consider doing it again I'll just pour gasoline on it and set it on fire instead.".

Well, that settles that lol. Thanks guys. I've had a couple of actual mechanics look at it and both think the seal is leaking, but can't say for sure. One says I should reseal the whole engine, for $2,000-$3,000 of course.

I have pulled the oil pan on Darth a number of years ago. It is a royal PITA to do as the exhaust pipe has to be removed, anything on the engine top that may hit the firewall. Once everything is loose, I usually take the radiator loose so it will lift with the engine. Remove the mount nuts and jack the engine up as far as it will go without breaking anything.

When it is as high as it will go, place blocks between the exhaust manifolds and the frame. This is necessary due to the mounts actually hanging down and under the oil pan flange. Once the mounts are off and the oil drained, remove the dipstick and tube (early ones are held in by a 5/8" hex then they are pressed in with a O-ring).

At this point, the pan can be dropped by removing the bolts, it will not come completely off at this point. In order to get it completely off, the oil pump and pickup have to be removed and dropped into the pan allowing the pan to be slid forward over the cross member and removed from the front.

The rear seal is a rope seal on the early engines and a two piece rubber lip seal on later ones. In order to change either, the rear main cap has to be removed and number 2,3 and 4 need to be loosened enough to let the crank drop slightly. If you have the rope seal, there is a special puller that screws into the upper seal to coax it out (good luck with that!), the rubber lip style should be staggered slightly allowing it to be pulled out. If you are replacing a rope type seal with a rubber lip one, the retaining pin in the lower cap has to be removed. Old mechanic's trick on rope seals: Using a punch and hammer drive the old upper seal ends up into the block, tightening it, use pieces cut off the old bottom section to fill the resulting gaps. Install the new lower seal portion and using a good sized hammer head to work the new seal into the lower cap until it is close to flush and use a razor blade to trim the ends flush with the cap. Oil the new seal and temporarily install the rear cap and torque all the caps. Rotate the crank a few turns and while you do this, take a good look at the timing chain. Once you have done this, remove the rear cap, examine the rope seal and if everything looks good, take some sealer and put a thin layer on the back portion of the cap behind the slinger groove to prevent leaks.

To replace a rubber lip seal, the old upper needs to be removed and same for the lower. In reinstalling or replacing a rope one, the split in the seal needs to be staggered in relation to the cap to block face, it is called out in one of the TSBs regarding the 460 rear main seal as it is the last Ford engine built with a 2 piece seal.

But Bill, you don't have a 4x4 crossmember.
There is no raising the engine high enough with the TTB.  (The engine hits the firewall first)

I find a two piece seal challenge enough to get right even on a stand.
The thought of doing it upside down in cramped quarters, and fishing the oil pump and rear sump pickup out of the pan without dropping the pump drive is enough for me to regard pulling the engine as the easier option.

Jim, I thought about you when writing that, but not having a 4WD (and not wanting one) I didn't want to post anything 4WD specific and be wrong. I did the pan drop on Darth when the pump strainer clogged a number of years ago. The trick to the oil pump drive is some heavy grease to hold it in the distributor shaft while you get an oil pump bolt started. I usually took the pickup off the pump when reassembling things.

You guys have me thinking. I found a one piece oil pan gasket. (I think from info on this site)

Had a mechanic who used to be here in town replace the rear main and pan gasket.

I know he had the exhaust loose or removed. He did it without pulling the engine. I’m wondering if he dropped the front axle down.

He’s worked mostly Fords, particularly Ford diesels and 4WD a lot.

I'll read up on the oil pressure switch and how to rule that out.  Are there any other things I should rule out that would be easier to get to?  I just fixed one valve cover gasket leak and there's no evidence of any leak from the other one.  

If you've observed the oil pressure sender/switch at the back of the block there is little else.

There could be a leak from the rear of the intake manifold at the china wall seal, but you would have noted that while looking at the sender.

My truck has a weeping RMS too.
It's not something I'm going to address until I can figure out a time and place to pull the engine.
I'll replace the oil pump -and the pan gasket, obviously- when I have some way to do that.

Yes, where the rear of the intake manifold hits the wall at the back of the block.  I've had two engines where someone did a very poor job of installing the intake and there was a leak there.  It is right in front of the oil pressure switch, and if either of those are leaking the oil will run down and look like a rear main leak.

If I were you I'd pull the air cleaner to get access to the rear of the intake and the oil pressure switch.  Check to see if there is any oil puddled on top of the block right behind the manifold.  If so you have to figure out from whence it came, but it'll be either the switch or the intake/block interface.

And while I can tell you are thinking "Please, not the intake!", I'll assure you that R&R'ing the intake is far easier than the pan.

Got it. Is there documentation here that would help me with a visual of where that is?  As you must know by now, I know my way around a 460 as well as a politician does the truth, so any additional hand holding would be much appreciated.

Here's a shot of the oil pressure switch on the back of Big Blue's old engine.  You can see the brass tee that screws into the engine, the steel tee on top of it, and the oil pressure switch coming in from the driver's side.  But that isn't the standard setup as you'll probably just have the steel tee and a switch screwed into it.

And the intake manifold is literally an inch in front of the brass tee.  It is the light gray thing.  The block is dark blue.  And where they meet is where that engine was leaking.

So you want to check out that area very, very closely.  If you have a leak there then do a happy dance 'cause fixing that is far easier than fixing the rear main.

Perfect, thanks.  I'll try to check it out this evening, fingers crossed.

I didn't see any evidence of a leak near that area, or anywhere near the upper half of the back of the block.  The rear half of the oil pan gasket on both sides has fresh, wet oil. Is there any point in determining if it's just the pan gasket or the RMS, or would you just replace both since I'd have to yank the engine either way?

If you are pulling the pan I'd replace the rear main seal at the same time.  The seal's cost is minimal and the labor cost for just getting to it will be significant.

If you’re going to change the seal, consider checking the seal crush.  Nothing worse than rework!

460Ford.com Oil Leak at RMS