Dare

I’m having trouble installing the rear main seal on my 951 and was wondering if anyone else has had the same problem (didn’t see anything in search). The problem is that the plastic covering the outer rim of the seal is being scraped off by the lip of the pry slot as I drive the seal in. Here’s a picture of it hanging out of the slot:This is the second seal that’s done this. The first time I thought it was due to the seal going in crooked as I was driving it (I was using a mallet around the outside edge). The second time I used a homemade seal driver that pressed it in pretty evenly. Still the same problem. Before driving the second seal I felt the bottom edge of the slot and it didn’t feel particularly sharp.

Has anyone had this happen to them? Did the seal hold with the side scraped up like that? (I assume not). Any tips on how to prevent this from happening again?

BTW, I’m using the Earling seal with a little Curil-T on the outside edge.

Richgreenster

With all of the required work to install a rear main, I would get a new seal. Also make sure that the outer portion of the block is not damaged. It looks like maybe it is where the pry slot is..

Dare

Definitely don't want to have to do this again after I've installed the engine. But now that I've had two seals do the same thing I'm hesitant to try again without knowing what's wrong.

The outside edge of the chamfer definitely has some nicks and dings, but the inside edge is pretty clean. I checked the mating surfaces before I assembled the bottom end and both the block and girdle were smooth and clean.

Its interesting that the outside lip of the seal bore is chamfered but the lip inside the pry slot isn't. I suppose I could round the inside lip of the pry slot with a dremel, although I'm not keen on grinding so close to the crankshaft.

xsboost90

make sure you push that seal in as far as it will go- ask me how i know.

Yarf

There is got to be a bad spot right were the seal is damaged, make a mark and take the seal out and make sure it is perfectly smooth

Mike C.

I think you have sufficient room to get in there and break that edge with the Dremel. I used oil to lubricate the seal surface so it would slide in easier (whew, don't take that out of context)...

JimV8

You'll want to get that little job right even if you have to buy a second or third one. Clean the opening really really well and put a drop or two of oil on the seal and it should slide in easy. Drive it all the way in and Bob's your Uncle.

Tom M'Guinn

I'd try the factory seal driver before grinding anything -- assuming that lip is not damaged or extra sharp. The factory driver centers the seal over the end of the crank.

Or maybe push up on the bottom of the seal as you drive it in.

John_AZ

Dare,

First, your homemade seal driver is an interesting design. using the flywheel bolt holes with a steel plate ----pressing on the PVC 4" screwcap with the center removed.

OK, If you had any burrs in the engine slot used to remove the old gasket, they will chew up the new $28 Elring seal. The edges have to be smooth--not filed down---just smooth.

The engine seal surface and the crank shaft have to be cleaned with a scotch brite pad to get all surface varnish off.

Curil T is a good seal for the outer RMS surface----remember to use conventional oil on the inner seal and crank.

I would not use your homemade RMS press. I want to see the seal insert without blockage.
Use the PVC screw cap and gently tap it in around the circumferance. You have a better view of the high and low edges of the seal and where to tap next. You do not have this with the homemade seal press.

The seal goes all the way to the bottom ridge of the block seal cavity. This should be below the bevel of the top engine seal cavity.

Picture credit --member-tyro

Get a new seal.

Dare

Thanks for the feedback everyone.

The tear notwithstanding, I thought my homemade driver actually did a reasonable job pressing the seal. The height of the driver is reasonably consistent around its circumference (+/-0.1mm). So I used the depth gauge on my digital calipers to square the top of the driver to the block and then advanced each nut by a half a turn, rechecking the alignment as the seal went in. You actually get a pretty good view of the seal going into the bore right up until it goes below the inner lip of the chamfer. At that point I removed the driver so I could gauge the depth. I finished up by tapping it with a mallet and a plastic dowel until it was below the inner lip of the chamfer by about 1mm or so.

I’m sure the factory driver is the ideal tool for this job (and at $160 it better be!). But given the success people have had with much cruder methods, I’m skeptical that it’s going to solve my problem.

I have another seal on order. This time I’m going to carefully file down the edges of the pry slot and apply a little oil to help the seal slide in. I’ll report back what happens.

944Ross

Interesting picture of the seal. Both the OP's seal and the one pictured are orange. The Elring ones are dark brown, the Kaco are black. That orange one looks like FelPro? Curious if there's an alternative as I am coming up on this job.

Dare

Actually I believe both pictures are of Elring seals. Certainly the one I installed came from Paragon in a sealed Elring box.

As I understand it, the benefit of the Elring product is that the ribbed portion of the seal extends across the entire mating face, whereas the others have a metal ring across part of the face. I suspect that this makes it less sensitive to incorrect install depth.

John_AZ

The Elring seal has a small double inner lip as well.

In the picture, the red seal is what most use if not Elring. Note the ribs on the outer surface go top to bottom.

The $20 Kaco seal (Pelican) is the seal I use. You will notice the ribs only go half way down. Most members will tell you to stay away from KACO--The Porsche OEM supplier.

I like the seal because it is easier to start. With Curil T on the outer surface you will get a tight seal. I use the PVC sewer cap to install my seal.

If you are not fortunate to have Curil T .
A lot of shops (and me) will spray WD-40 in the engine seal cavity thoroughly and use conventional 40-50 wt oil on the crank shaft and inner seal.
The WD-40 lubricates and after time gets "gummy" and seals well.

Note: all seals will leak if there is a seal groove in the crank shaft. Just like the crank seal will leak if there is a groove in the oil pump sleeve. If you see a seal groove, make sure the seal you are using is not touching the RMS seal lip.

GL
John

944Ross

Quite a bit of chatter in old threads saying the brown Elring is the only one to use; that the Kaco's leak after a year or so. My understanding was that the Brown Elring is fluoroelastomer, the others are nitrile rubber or similar. Is the best Elring now the orange one?

Dare

Interesting. Thanks for the insight. I actually bought one of the OEM seals before I read about the Elring being better. I'll have to think about whether I should try this seal instead of waiting for another Elring. Can I ask you how many times you've successfully used the KACO seal?