Stubborn rear main seal
 

Trying to replace my rear main seal, which was starting to leak, before reinstalling my transmission. Can't take off the retainer / end cover because I'm using the oil pan to support the engine while the transmission is off. Shouldn't be a problem, I thought, the Haynes manual says that it can be done without removing the retainer, just use a screwdriver to pry it out along the outside (and don't nick the crankshaft). I also read a few threads here and elsewhere that confirmed this has worked for others.

It's too tight, screwdriver didn't work. Tried something else I'd read about -- I slowly, carefully drilled a small hole through the metal ring in the seal (just a millimeter or two -- I'll check for shavings inside when I get the seal out), put in a wood screw. Screw holds solidly to the seal, but still I can't get the seal to budge. Tried pliers on the screws, bent the screw, seal didn't budge.

I'd appreciate any thoughts. I thought about heating the aluminum seal retainer a bit, but I don't want to damage the silicone seal between it and the block. Maybe the pressure of the engine on the oil pan is pressing on the retainer and holding the seal in? Or are they just really tight sometimes? Any suggestions would be welcome.

Thanks!

Re: Stubborn rear main seal
 

The seal is probably just really tight.
I drive a screwdriver in at the outer edge and pry to collapse the metal inside the edge of the seal. Once it starts collapsing it gets easier for the seal to break free of the casting. Don't damage the casting though.

Re: Stubborn rear main seal
 

Drive in a screwdriver, as in with a hammer? It doesn't gouge the aluminum?

Re: Stubborn rear main seal
 

Yes it can gouge the aluminum. It's easier to correct that area than it is to repair a gouge in the crankshaft surface though. The rubber coating on most seals will take care of a light scratch in the aluminum.

It's really hard to describe the technique I use in words.

My 'seal screwdriver' is sharpened on the tip, and semi-rounded on the tip.
I drive it in at an angle, then twist the handle to roll the outer edge under, and pry to force the entire seal outward.

You could try a paint can opener. Check this video (also note he shows a screwdriver and holds it about the same angle that I would drive it in, even with the parting line and 45* from the surface, if that makes any sense)

Re: Stubborn rear main seal
 

I used a paint can opener on my 6th gen after watching that video and the front crank seal removed smoothly within a minute without knicks. IIRC I used a pick to lightly dig in to gasket enough to lift it up and slid the paint can opener behind the seal.

Now, if I would have followed the FSM instead of contacting a Felpro tech and following his advice to not use Hondabond on the corners of the oil pan gasket the engine would almost be oil leak free. I'm pretty sure it has a rear main seal leak too. I used STP stop leak on it a couple years ago and that did slow it down to just a few drops overnight.

Re: Stubborn rear main seal
 

Thanks. I tried the paint can opener. Wasn't able to get it in on the outside because the crankshaft was in the way, but was able to carefully get it in the crankshaft side. It's round on the back so I figured I could do it safely without knicking the crankshaft.

Pulling straight out had no effect, engine's shifting all over the place, the seal won't budge. Skinned my knuckles pretty good though. Put heavy gloves on after the first attempt... I tried prying. Seal didn't budge, just bent the paint can opener.

I haven't yet been able to get a screwdriver in along the outside, even with a ball peen hammer, and I haven't been able to start collapsing the ring. I mean, I could get a heavier hammer and really wail on it I guess... At this point I'm not sure what else to do...

I tried another couple of screws in the hole that I drilled, put a wood block against the engine and pried on the screw with my slotted trim panel tool. More skinned knuckles and one hell of a projectile when the screw finally popped itself loose.

I may try to rent an engine crane of some kind so I can take the jack off the oil pan, remove the pan and seal retainer, and do it that way. It'll add expense and probably a day to the job but I'm not getting anywhere - it's like the seal is fused to the block. If I do go the route of removing the seal retainer, can I use the same Hondabond HT between it and the block that I used for the transmission case? The part no. in the FSM is different...

The only other thing I can think of is to drill holes all around the seal and hope that that weakens it enough to collapse and come out. Or more aggressive hammering. Possibly explosives.

Re: Stubborn rear main seal
 

Use the same stuff. Their 4 varieties are all fairly interchangeable now.

Re: Stubborn rear main seal
 

Got it! (Very exciting for me). What worked in the end was a modified form of your technique, ezone.

I figured out how I'd replace the seal retainer as a backup plan, and once I had that I felt much freer to risk a bit of damage to the aluminum.

Nevertheless, I could NOT get a screwdriver between the casting and the seal, even with my smallest and sharpest screwdriver and my biggest hammer.

So I punched a couple of holes in the steel ring, enlarged them so I could get some big screwdrivers in from the outer edge toward the inner, and pried and pried and pried. That was enough to move the outer edge of the seal by about a millimetre, though only in the area right around the holes. It was enough though that I COULD now drive a small screwdriver in between the seal and the aluminum and eventually pry out the seal. Took about two hours once I started down this road.

So the plan now is to install the new seal (I didn't knick the crankshaft as far as I can see and there seem to be only minor scratches in the aluminum), fill it with oil and wait a few hours before installing the flywheel in case there's a leak. Anything else I should do or watch out for?

Thanks all! I'm really grateful for the advice!

Re: Stubborn rear main seal
 

Make sure new seal is driven in far enough and evenly.

Not sure why you want to wait. Slam it all back together and get it over with.

It cannot leak with the engine off.
If it's gonna leak it won't leak until the engine is running.