Crank Main Seal Replacement

[FL911SC]

Greetings All,
I am looking for a post and/or some helpful tips on replacing the rear main seal on the engine at the fly wheel.
Wayne's 101 Project book says to remove it with two screw drivers, then tap the new one in with a "dull hammer". The Bentley's manual calls for a special tool, which I don't have.
As simple as this task may be, I am scared to death of it. A few years back I had the seal professionally replaced when a new clutch was being put in, it has leaked ever since. I liked the shop, but if they can get it wrong, then I can most certainly get it wrong.

If there is post that answers these question, please point me to it.
Here are my questions:
1) I have read people having trouble getting the old seal out using 2 screw drivers as outlined in Wayne's book. Is there a better way which reduces the chance of damaging the seat?
2) Lubricating the seal, what is the correct approach? Wayne's book makes no mention of lubricating the seal. I have also read: it depends on the type of seal; or Only the inner part and not the outer; or both inner and outer. What is correct?
3) Are there any tips for putting in the new seal? Is it really just as simple as going around it with light hammer taps?
4) At what point is the seal fully installed? I think "Flush with the outer ring" is correct, but what to be sure.

Thank you for helping a novice. I have witnessed the mess a leaking seal makes and what to get this right so I don't have to do it again... at least for a while.

Thanks!! Keith P.

[proporsche]

1st get yourself the right seal which is this one Elring ..no others.....

next is there is a slot of flat head screwdriver on the case where you put it and pry it out removing it.
Yes there is a special tool for the installation but no need to have it.I use (for over 38years) two hammers one smaller to guide it in and the larger i use on the smaller one.But 1st you slide it on the crankshaft gently no lubrication needed by twisting it let`s say clockwise just a little turn .
next i use rubber hammer and finish it with flat side of the smaller hammer.
start with the red on left with copper end and rubber hand then i use the red handed on right..............and yes flush is correct...

Ivan

[FL911SC]

Ivan,
Thank you very much for the information. It is very helpful!
To clarify on the seal, is this the same seal offered here on Pelican? HERE

I had been warned about buying the right/wrong one and had been told, by someone who had previously worked at a shop, that they had never had a problem with the Porsche branded seal. They are expensive, but figured it was worth it to get it right.
However, if you swear by this one after 38 years, I will take your advice.
If the Elring one is the one on Pelican, then that makes it simple. If it is not the same, then were would I source it from? For what it's worth the one on Pelican does have good reviews.

Lastly, I don't have the same hammers you do, but I think I have the idea. First, I should NOT use a block of wood to help tap it in. Soft even taps with a rubber mallet or flat face hammer should do it. Once I get close, I may turn the hammer on its side, then tap with a different hammer, to make sure the seal is flush and not more. Does that seem right?

Thank you again!
~Keith

[yelcab1]

I just did both seals front and rear on a 964. The only tools ever needed were a hammer (any will do) and a piece of wood 1x4 by 10 inches long. Get the seals started with your hand, tap in place until flush with the case.

[proporsche]

Originally Posted by FL911SC

Ivan,
Thank you very much for the information. It is very helpful!
To clarify on the seal, is this the same seal offered here on Pelican? HERE

I had been warned about buying the right/wrong one and had been told, by someone who had previously worked at a shop, that they had never had a problem with the Porsche branded seal. They are expensive, but figured it was worth it to get it right.
However, if you swear by this one after 38 years, I will take your advice.
If the Elring one is the one on Pelican, then that makes it simple. If it is not the same, then were would I source it from? For what it's worth the one on Pelican does have good reviews.

Lastly, I don't have the same hammers you do, but I think I have the idea. First, I should NOT use a block of wood to help tap it in. Soft even taps with a rubber mallet or flat face hammer should do it. Once I get close, I may turn the hammer on its side, then tap with a different hammer, to make sure the seal is flush and not more. Does that seem right?

Thank you again!
~Keith

yes that is the one ,also get one the same brand for the front pulley while you are at this ...also Elring...and yes on the procedure with hammers ,has to be flat towards the seal ..

[88911coupe]

I seem to recall when I rebuilt the engine in my '88 that there can be a a worn area on the crank sealing surface and it's best to not let the new seal ride exactly on that "ring". Not sure if that is a correct recollection or not.

[FL911SC]

Thanks to each of you. I can't tell you how much the answers and feedback help.
Just ordered the Elring seal. And $1400 worth of "while you're in there" stuff.

Regards,
Keith P.

[Long Nose]

I just did it since I had the motor out of the car. It was not as hard or scary as I thought. You don't have to set endplay or fiddle around with shims like you do on a VW rear main seal. Here are my thoughts / tips:

1. To remove the RMS, you also have to remove the flywheel. Since these have so much torque, was worried about stripping a nut, etc. But, as long as you have the flywheel removal tool and a large socket and breaker bar, the bolts came out easily and were not seized up and I didn't strip them.
2. I had to take the engine off the stand, because my engine yolk didn't have the clearance I needed in order to fit the flywheel removal tool and the 1/2 driver with breaker bar etc. So, I needed an engine hoist to lift the motor off the engine stand, I built a frame out of some 4x4 posts on a H/D moving dolly, and sat the engine on the exhaust headers, and the engine was safely supported but I could also move it around a bit.
3. In the past I have used a self tapping screw to screw into the RMS and extract them, but that was on a VW Type 4 motor and that RMS is installed while the case is split, and they are really hard to remove. I didn't need to do any of that, using a screw driver the seal came out NP without damaging the case, easy peasy...
4. Putting the new seal in was a bit more challenging, just to get it in straight. I used a little bit of crank case sealer around the outside edge of the seal, and lubed the inside. The challenge was to seat it square to the case without pushing one side in too far, because its not a very deep seal. So, mine ended up about 2mm past the case, so not flush with the case. I figured this would be OK and better than risk damaging the seal by removing it and try and reinstall it twice. I also figured that being set slightly past the case but square was better than being flush with the case on one side and 2mm inset on the other side, and being crooked in the bore. So, I just made the seal square in the bore but slightly inset from the outside of the case. I am sure someone here will tell me if I am completely wrong and compromised my seal.
5. My torque wrench only goes up to 85Ib/ft, and the spec for the flywheel bolts is 100 Ib/Ft, so I had to do some extra math to apply 100 Ib/ft by getting 50 Ibs on the breaker bar 3 feet away. However, I would suggest borrowing a torque wrench to get the correct torque. Also, there is nothing in Waynes book about the sequence, it just says put the flywheel on and torque it down. However, torqued the flywheel on in increments, starting at 25 Ib/ft all the way around, then 50 Ib/ft, then 75 ib/ft and then finally 100 Ib/ft. I also went "lugnut" style, so torqued the bolt across the center of the bolt that was just torqued instead of a radial pattern. Not sure if that makes much difference but I didn't want to warp my flywheel.
6. While I had the flywheel off, I took it into the local machine shop and they resurfaced it for me for $50, so I have a nice smooth flywheel when it goes back together.
7. Made my own flywheel clamp out of pre drilled flat bar that I had lying around. Slipped one end over the existing bolt on the bottom right of the crank case and used one of the pressure plate bolt holes and bolted the bar on and that seemed to do the trick to hold the flywheel. Carful not to spin the flywheel in the wrong direction when you are matching up the bolt holes, I read somewhere that spinning the 911 motor in the wrong direction too much can affect the valve timing chain. So, I didn't want to take a chance.

Thats all I can remember off the top of my head. The motor not back in the car yet, so don't know if the seal is working, but figure it's better than the old one which definitely was leaking. Please feel free to correct me if I did something wrong...

Here is a photo all done. Gets a little frosty up north here, so have a little wood stove to keep me warm...

[Long Nose]

Oops, U/L same photo 2x... here is my car.

[$yncro]

I just did main seal today.. well attempted I guess..
I use the wood block method and no success.. I tore
The edges of the seal..! Very annoying! Have to get me
A new seal or can I still use this.

[FL911SC]

$yncro - your experience trying to get the seal it, with no success is part of the reason I am so nervous about the seemingly simple task. Seems a little oil would help, but would lessen the seal's ability to create a tight seal at the same time. With the advice above from Ivan, I will resist the urge to lubricate the seal.
As for your seal, it looks like only the fist sealing ring is damage, so there is a reasonable chance it would be OK. That said, and in my humble opinion, I would not risk it. It is too much of an effort to change again should it leak. Trust me, it makes a heck of a mess when it is leaking. I would spend the money and time on a new one. In the mean time, use that one to practice so you won't have the same problem again.
Just my 2 cents.
Thanks, Keith

[yelcab1]

You got that seal started in crooked, that is why it rips.

[proporsche]

Keith..do not worry too much...use only your hand and a little twist to push it in .Once you have it strait apply more pressure and the hammer--gently ;-)))

Ivan

[Walt Fricke]

If you have a suitable tool, like the one you'd use to deburr the edge of a drilled hole (small curved blade in a handle, rotates as you go around the hole), you could break the square edge of the case where the seal goes in. That might help avoid tearing, and ease the all important first little bit of the start. Once the seal is in far enough so that one side doesn't pop out when you press on the other, you are usually good.

[$yncro]

I know Keith.. to be honest.. I was a bit impatient when I tried installing.
I know better now. Ordered a new seal too.
Cheers!

[HaroldMHedge]

In the 911 Engine Rebuilding Forum, there are several good examples of home made tools for installing the seal.

do you really need oil seal installation tools?
porsche tool 9517/1 - one piece $4.75

[FL911SC]

Originally Posted by proporsche

Keith..do not worry too much...use only your hand and a little twist to push it in .Once you have it strait apply more pressure and the hammer--gently ;-)))

Ivan

Thanks again Ivan. The Elring seal is on order and I waiting for it.

[burgermeister]

Originally Posted by 88911coupe

I seem to recall when I rebuilt the engine in my '88 that there can be a a worn area on the crank sealing surface and it's best to not let the new seal ride exactly on that "ring". Not sure if that is a correct recollection or not.

I seem to recall the exact same thing - mine always weeped a little, not enough to drip but enough to get everything behind the flywheel wet. I installed the last seal 1mm proud, or maybe it was 1mm 'too far' in, and it stopped weeping. I do have 218K miles on the car.

[Flojo]

Originally Posted by 88911coupe

I seem to recall when I rebuilt the engine in my '88 that there can be a a worn area on the crank sealing surface and it's best to not let the new seal ride exactly on that "ring". Not sure if that is a correct recollection or not.

exactly.
this is why you get the elring type 311.898
is has two lips sitting at an other angle thus not seating at the worn spot.

[Quasimoto]

My flywheel seal was tough to get out as well. Couldn’t get much leverage with the two screwdriver method. It’s been there 36 plus years and didn’t want to move...

Bent up a small scrap of sheet metal with a small lip to protect the edge of the crank hub. Great leverage once you poke under the metal inner ring and almost zero chance of marring anything.