mkhargrove

I read a few posts on different threads which mentioned rear main seals leaking after replacement. I'm sure there are several reasons that would happen, but it occurred to me today when i replaced mine that I don't recall seeing anyone mention anything about trying to get the metal where the inner lip of the seal rubs as smooth as possible. I noticed when i removed my old one and cleaned the area that the surface of the steel showed a little discoloration....the type that you get when oil more or less cooks on over time. And, even though I had wiped it down, I could see varations in the reflectivity of the steel. I used a bit of gasoline on a rag and spent about two minutes really trying to polish the area, and the surface appears to be much smoother....which made me think that had I left it like it was, the surface would have been more abrasive and uneven against the rubber lip.

I don't know if it will make any difference, but I just thought I would throw it out there just in case it might help someone to do that in the future.

My apologies...my phone was dead when i was working on the car, so I didn't get a before and after pic. I snagged this one just to show the area that I'm talking about

dr bob

The mostly likely causes of a new seal leaking, in my limited experience, is poor installation and prep. As you point out, there's the chance that a sealing surface is contaminated. Great idea to get that as clean as possible. Pay the same attention to the OD of the seal area where the seal fits in the cavity. The block and girdle split there so there's a chance for seepage through the split. Plus any old debris, like sealant squeeze-out and film from a previous seal installation, risks a leakage path around the seal.

To get a lip seal to seal correctly, the surface on the crank is polished to a cross-hatch originally. The seal lips ride on a thin film of oil, so we expect the ground surface to still be hatched as original. When you are installing a new seal, make sure to pack the cavity between the seal lips with your favorite assembly lube, or my favorite Vaseline in there. Absent that good initial lubrication, the little sharp edge of the seal lip will get scuffed off, and from then you'll have seepage.

Lips seals must be installed perfectly square to the crankshaft. As tempting as it might be to just tap the seal in with a small hammer or mallet, use a real seal driver. You can come up with an installer made from PVC pipe sections to put even pressure on the outer face of the seal, giving you at least a chance. The seal should sit square in the end of the block, and no deeper. The back of the recess is nowhere close to square and clean, so you can't depend on it to hold the seal square. If you end up with the seal in too far, pull it out, frame it and hang it on the wall and put the spare one in. The 'must be square' requirement considers how the seal rides on the crank. If the seal is at all crooked, the seal lips will wipe a little sideways, you lose the oil film under the lips, and the seal is quickly worn and will leak. OK to use a very thin wipe of non-hardening sealer on the OD of the seal itself, just don't put any in the cavity as the seal will just wipe it off and pack it in the back of the cavity.

So: Clean, square, in the right place, lubricated seal lips, a film of sealant on the outside of the seal.

Oh -- Make darn sure you don't scratch the sealing surface on the crank. Repeat that ten times.

Tails

I totally agree with Dr Bob. Every thing must be in perfect alignment and sealing surface "pristine"

mkhargrove

I wish I had taken pics. The "stains" left by baked on oil don't wipe off with a rag. If I had it to do over again, I would have used a bit of metal polish to buff it out even smoother.

I see posts with differing opinions as to whether or not grease, vaseline, or oil should be used. It made me wonder if silicone lubricant might be an alternative.

Ad0911

There are a number of RMS insertion tools on the market. Like this one:
http://www.arnnworx.com/catalog/inde...roducts_id=327

Any good?

GregBBRD

Depending on the depth that tool puts the seal in (let's assume they did their homework), it should work fantastic.

GregBBRD

Perhaps worth noting, I had two engines with micropolished seal surfaces which leaked, on my engine test stand. One engine we put 3 seals in, before we found one that would not leak. The next engine, we got smart and put in one of the seals that did not leak in the first engine, for the second attempt.

I have not been using seals that come in the Victor Reinz gasket sets, for quite some time.

My time is more valuable than the price of a seal.
And if the seal leaks after the engine is installed on an automatic, the seal could cost $500 and still be a bargain!

mkhargrove

oh, i totally agree.

i have a question for you, Greg.....were you driving those in with a hammer or whatever tools, or using a seal press of some kind?

i ask because i know it's common for people to drive them in with a hammer. that alone, if not done properly, can stretch the seal. i would say that if you've driven one side in to flush while the other side is only half way in, that seal will leak.

Kevin in Atlanta

I have found the Porsche sourced seals install easier. Reinz seem to need some finesse to get started.

Once I have the seal started and square I use a 19 - 21 mm socket upside down to tap it into place.

I hang the edge of the socket outside the seal edge and tap the seal in waiting to hear the sound of the socket hitting the block. That way the seal cannot go in too far.

firemn131

I have used this contraption the three times that I have replaced a RMS.
A 3x2” reducer glued onto a 4 “ long piece of 3”(ID) pipe.

SeanR

This is the one I use and I can't remember where I got it.

davek9

OP, your RED arrow is covering it, there is a "notch" in the block that assists seal removal, and also note I've see two types of seals over the years, one with a steel outer lop and one w/ just rubber.
Whichever one you use, make sure you insert the seal in it far enough to cover that "notch" as well as being "square" as others have noted

Dave K

dr bob

As far as choice of lubricant, use whatever you are sure will stay in there until the engine starts and oil makes it behind the seal, .and. washes out when oil does get there. Engine oil is great if you will be starting the engine within, say, a week. Engine assembly lube is great but not everyone has some handy. Vaseline checks all the boxes in my experience.

We didn't mention anywhere how important it is to protect the seal lip(s) from sharp edges on the end of the crankshaft as you slide tap drive the seal into place. If in doubt, I sometimes wrap a bit of packing tape right on the end of the crank to help the lip get past. There isn't a lot of room to work on the end there, and the tape must not end up in the lip once installed -- no way to get it out out clean and no damage to the seal. Lubrication is key here too.

GregBBRD

Original Factory Installation Tool. I've had it since the late 1970's. Because it stops on the flange of the crankshaft, every seal is laser straight in relationship to the crankshaft (The blocks are not good references for installing

the seal.. This poor tool has installed literally thousands of flywheel seals....so many that I've and squared it up (to confirm it is still viable), several times, over the years.

SeanR

I've got the 9125 for the front and after looking at it I figured the RMS P-tool wouldn't work with the engine in the car/auto trans pulled back, but that looks much smaller, does it fit with pretty easy with minimal auto yanking?