rear main seal install

[logic23]

OK my question goes out to all of you who build EJ engines quite a bit. When you install the rear main seal how deep do you drive it?

I have seen them in a lot of different places, mostly fush with the bevel. Thanks

[subaru360]

It should be flush.

[logic23]

if you tap it in farther will it leak? seems weird that the recess is so big

[Fairtax4me]

It shouldn't unless the crankshaft is damaged, or has a varnish buildup that gets loosened up and damages the seal. Technically it is better off in a different position than the original seal. Any seal will almost always leave a groove where it has been riding against the shaft it is sealing. By placing the new seal in a slightly different location you essentially move to an untouched surface of the shaft and should get a better seal for a longer period of time. But most of the time the original location will suffice.

[GeneralDisorder]

It should be flush - there are often drain holes behind the seals that you don't want to block by fully seating the seal against them.

 

If the shaft has a groove in the seal lip location then it should be rectified with a speedi-sleeve, etc prior to installation of the seal.

 

GD

[99ImprezaOSport]

Technically it is better off in a different position than the original seal.

 

I have agree with a slight offset. I taped mine in about 1/32" to 1/16" from flush. I replaced my rear main at 180K and another 30k I was able to get a good look at it when I replaced the tranny. It was dry as a bone in that bell housing.

 

Don't forget to change out the baffle to the aluminum version while you are in there...

 

Some images:

 

Regular size picture of rear main seal and baffle LINK

 

Same image Extra Large LINK

[Ionlyhave3suubs]

I can see this thread is a few months old but I am hoping to get a reply from this post. My current project is a 97 Outback 2.5 dohc I have had since 98. 230K miles, finally have to replace the ORIGINAL head gaskets. After getting the engine out I discovered the cheap plastic plate was leaking AND the rear main seal was leaking also. Well I removed the old main seal and drove in a new one. There was a groove in the crankshaft, so I elected to drive it slightly deeper. Unfortunately it was slightly un-even looking and I tried to even it up as I drove it in, it kept getting deeper, but I was not satisfied with how even it looked until it was all the way in. It is at an even depth all the way around now, but I am concerned it may be in too deep and may leak now. It looks like there is enough room to install another seal in there. Do I need to pull this seal back out and try again? I don't want to get the engine in to find out I drove it in too far and have a leak. If anyone has any experience with driving the seal in that far successfully without leak, please let me know. I know I'll have to ruin that new seal to pull it.

[Crazyeights]

I think I would pull it out and do it again. Like GD said you don't want to block any drain holes that may exist. A new seal is only another $20.00 and you be kicking yourself if you have to pull it all back out again.

[Ionlyhave3suubs]

One other question on this, When you install this seal, do you use any sealant on the outer surface of the seal where it mates to the bore? I know to lube the inside.

[Fairtax4me]

Don't know that I would be worried so much about it leaking, as I would about it rubbing or blocking something. If it's in there really deep it's probably going to be a pain to get the thing back out. Be careful and don't scratch the crank.

 

On most seals I usually use a small smear of sealer on the outside, but these moulded silicone types will seal themselves. Just use some oil or grease to lubricate the outer edge to help it slide in. And always lubricate the inner part that rides against the crank with fresh motor oil.

Edited November 26, 2010 by Fairtax4me

[idosubaru]

no sealant. i'm sure you can get away with it, but they aren't designed with sealant in mind.

 

i'd remove the old one, that seems odd to leave it there. it might be blocking holes, you could check if it is or not and then decide....but then the outer most seal probably won't see much oil or typical supply so it could dry out, or not perform as designed over a long period of time? doubt it, but i would think it wise to get the old one out as it serves no purpose at all if you properly install another seal which is the only way i'd be dropping an engine in there anyway.

[Allenharveydale]

I can see this thread is a few months old but I am hoping to get a reply from this post. My current project is a 97 Outback 2.5 dohc I have had since 98. 230K miles, finally have to replace the ORIGINAL head gaskets. After getting the engine out I discovered the cheap plastic plate was leaking AND the rear main seal was leaking also. Well I removed the old main seal and drove in a new one. There was a groove in the crankshaft, so I elected to drive it slightly deeper. Unfortunately it was slightly un-even looking and I tried to even it up as I drove it in, it kept getting deeper, but I was not satisfied with how even it looked until it was all the way in. It is at an even depth all the way around now, but I am concerned it may be in too deep and may leak now. It looks like there is enough room to install another seal in there. Do I need to pull this seal back out and try again? I don't want to get the engine in to find out I drove it in too far and have a leak. If anyone has any experience with driving the seal in that far successfully without leak, please let me know. I know I'll have to ruin that new seal to pull it.

 

Put it out flush! I've had that motor of mine out Three times to figure out what the real problem was! The first time I started it it leaked, so I thought maybe I had cracked that cheesy little black plastic cover. I took it out and replaced the plastic with an aluminum cover and it still leaked! The third time I had it out I finally figured out it wasn't the cover but the depth at which I installed the main. I know your frustration, seems like it should be set back in to the stop> I won't have to do that again,I hope. gave the chance to hone my installation/removal skills though!

[Allenharveydale]

Out flush-It took me three tries to figure this out or it GUARANTEED to leak!

[1-3-2-4]

I don't see the big deal over this seal is about.. just find a pipe or whatever the same size as the seal and tap it in

[GeneralDisorder]

I don't see the big deal over this seal is about.. just find a pipe or whatever the same size as the seal and tap it in

 

The problem is the depth that it is driven in to.

 

If you drive it too far you partially block the oil drain-back hole. This causes oil to pool at the seal and causes a leak in short order.

 

It is also a large diameter seal - if it is not carefully driven to an even depth all the way around the seal runs on an oval-shaped shaft (cross-section of round shaft taken from a non-perpendicular angle) - this causes uneven lip pressure and damages them pretty quickly.

 

Correct sized driver is a 3" ABS pipe coupler. I use a "drain clean out" and install a threaded cap in the end.

 

GD

[Gloyale]

 

Correct sized driver is a 3" ABS pipe coupler. I use a "drain clean out" and install a threaded cap in the end.

 

GD

 

Bingo.

 

I actually use an 3" "end cap" piece as my installer. Perfect size, and it has a nice big flat spot in the middle to whack with the rubber mallet.

[davebugs]

I use the 3" coupler. Often with a piece of 2x4 over it to help the pressure be even when hitting with the hammer.

[1-3-2-4]

Bingo.

 

I actually use an 3" "end cap" piece as my installer. Perfect size, and it has a nice big flat spot in the middle to whack with the rubber mallet.

 

Thats the same way I would of done it also.. When I did the front crank shaft seal I used the largest axle nut I could find and drove it in just like the FSM said.. 3 years later no leaks.

[davebugs]

Thats the same way I would of done it also.. When I did the front crank shaft seal I used the largest axle nut I could find and drove it in just like the FSM said.. 3 years later no leaks.

 

 

 

There is another size PVC coupler that will do bothe the crank and cam seals. I always put the same smooth side towards the seal. Because the other end gets beat up some from hitting it. Then again my current coupling has probably installed over 100 Subaru seals.

[Ionlyhave3suubs]

Ok, I got the seal back out and re-installed another new one flush. Thanks for all of the responses. In case anyone is wondering how to remove a seal buried that deep, I used the drill and sheet metal screw technique. Drill 4 holes in the metal part of the seal evenly spaced around the perimeter. Run a sheet metal screw through a fender washer then screw it into the hole you drilled in the seal. Use a extra washer as a spacer on the flange side so the screw is straighter and slowly and evenly tighten all four screws, a little at a time. Works great as a seal puller. You can use more than 4 screws for this, the more the merrier, but I wouldn't do it with less. Some of your screws may pull out, that's ok, just drill a new hole 1/4" over from the one that pulled out and put the screw in and tighten as already mentioned. Be careful not to mar the crankshaft or the seal mounting surfaces. This process took about 15 min. If I was doing it over, I would have started with 6 screws instead of 4. I only had 4 matching size screws available at the time so that's what I used (I'm 20 min away from the nearest hardware store).

 

Front seal and cam seal driver, 32 mm socket- same one used on axle nut!

[Fairtax4me]

Now cross your fingers and wish upon a shooting star that it does't leak!

 

JK glad to hear you got it out and replaced.

Drilling holes in the seal? Braver than I.

[Ionlyhave3suubs]

I read the drill and screw technique before, thought I would try it. As deep as it was, not sure how else I could get it out with out boogering the block, crank or both without cracking the engine in half. I'm thinking when the engine finally goes, I'll either buy a wreck and pull the motor and part the rest out or I'd really like to try to tackle a JDM twin turbo swap. The wiring scares me though.

[1-3-2-4]

The problem is the depth that it is driven in to.

 

If you drive it too far you partially block the oil drain-back hole. This causes oil to pool at the seal and causes a leak in short order.

 

It is also a large diameter seal - if it is not carefully driven to an even depth all the way around the seal runs on an oval-shaped shaft (cross-section of round shaft taken from a non-perpendicular angle) - this causes uneven lip pressure and damages them pretty quickly.

 

Correct sized driver is a 3" ABS pipe coupler. I use a "drain clean out" and install a threaded cap in the end.

 

GD

 

Doing this this time around last time I used a pretty thin plastic cup with the same diameter but it must of not been seated all the way oil loss was substantial also with smoke coming from the hood.

[ivans imports]

flush is good i glue them in with ultra grey and stake them in nothing worse than blown out rear main must use the brown seal from subaru

[1-3-2-4]

I guess you are talking to me? my first one was from Fel-pro and the 2nd one I have is from Subaru.. they look the same as expected but the price was the same after shipping so I just picked it up at the dealer.