Lizard928

the area dinged doesnt seal so you are fine, you can remove the majority of the sharp pieces of metal with a fine file, and it would be ok, just dont leave that bevelled plain when using the file. Emory cloth will work as well, just will take longer.

Rob Edwards

Only on Rennlist can you get multiple good opinions on how a hack mechanic can de-burr a 928 crank without destroying it, at 10PM on a Friday night, for free. I love this place! Thanks for all the help!

Bill Ball

Just one hack mechanic to another in my case, but fortunately there are some pros in here to keep us from completely messing up.

Hope the rest of the job goes easier. Driving in the new seal may be a challenge that could use some sage advice as well. I still had the TT in-place, so I had little room to get any tools in there. The seal tends to **** to one side or the other, and it is critical that it get started straight. In my case, it just took many attempts before it stuck evenly. That was 80K mile ago, so I guess I did alright. You should have room to use a seal driver, even if improvised from PVC pipe. Just go very slow, checking for squareness until it is clearly engaged on all sides. Defintely lube the inner seal lip. I suppose lubing the outer edge might help it go in, but I don't recall doing that.

RyanPerrella

yeah Bill face it buddy, you are one of those pro's that allot of us count on.

Thanks

the flyin' scotsman

A trick for seal removal I've used with good sucess is to screw in 2 self tapping screws 180 degrees from each other into the seal. Once you have them in use 2 sets of pliers to evenly pull the seal out..........presto.

Crocus cloth should be able to remove any small nicks/burrs.

928ntslow

As far as installation of the new seal. Either way in tight quarters or not, use the old seal to instll the new one. Make sure the seal channel is CLEAN! Often there are bits of the old seal still affixed to the block as the engine has gone through a gazillion heating cycles. I had spent 20 minutes or so scraping bits out of mine. Use compressed air, NO BRAKE KLEEN!!!!. You can also use a clean cloth. Lube the seal and channel and don't attempt to knock it in flat from the start. I sink the upper side first and then stretch the seal around to the bottom. Just get the top in enough to bite. Then take your old seal and turn it around so they are face to face. Take a ball peen and gently tap tap tap around working your way to the bottom. At the bottom, you will have more room to whack it a bit harder. You want to get the last part stretched over the crank. Once that is done, you then keep tapping around the seal to to seat it. I tend to drive mine in further than the original, but not too much where it can't be removed just as easily as the original. The last thing you want to do is THIS job TwICe! Don't ask me how I know....

Good Luck Rob!

RyanPerrella

Rob,

I sent out the breather today. But with the holiday it maybe thursday before you get it.

marton

I have seen this advice before but I was never able to actually screw in 2 self tapping screws; even when i tried to drill pilot holes with a BIG 2 handed Bosch drill. Myself I finally hammered in 2 screwdrivers on opposite sides and levered it out. Important to mark the screwdrivers with slightly less than the seal width before you start.
Guess i am just a weak european...
Glad you got it out finally

Marton

Rob Edwards

Update: I had my RMS re-replaced today. I thought I got mine in the right way in December, and Greg at Precision said my install looked good but was leaking like crazy. Turns out I had purchased two RMS's and by chance had installed the more difficult one to seat properly. BTW, an RMS is 6 book hours on a GT.

Turns out there are actually three flavors of RMS's. The factory ones (as shown in my pictures above) are maroon and have a rubber coating on the entirety of the outer circumference. Duno whether they're NLA or not. The replacement RMS that I installed in December had a black rubber coating that also covers the entire outer circumference. There is little 'contour' to the underlying metal on this iteration, so it's hard to get it started. I also had (but didn't install) the most recent OEM replacement, which only has the rubber skirting over half the outer circumference, and has a pronounced curvature (visible below) that eases gettign it seated, or so says Greg (I'm inclined to believe him!)



Note the curvature at the top lip:



Interestingly, I bought both 4 months apart, from the same vendor in July and November 2007. (Yes, I'm often an idiot....) I got the 'good' RMS in 7/07, which came with the 999.113.426.41 part number, while the other RMS (purchased 11/07) had been superceeded by 928.113.426.41. Weird. Maybe the vendors can comment on which one is available and whether it's the 'countoured' model?



So I now have a spare for 100,000 miles from now.....

Tails

Rob,
I was always taught when working on bearing journals and seal surfaces never use emery paper, because if the emery detaches from the backing and get into the bearings or into the oil ways you can have disasterous consequences, as the emery material is harder than the bearings, journals and seal faces.

We always dressed up any marks, scratches or indentation by using an oil stone or for for getting into tight spaces a small "slip" oil stone, dimensions of say 2.5 inches long, 0.5 to 1 inch wide and around 0.25 inches thick. I now use these small stones to sharpen my fishing hooks.

The marks on the outer edge would be best taken care of by the use of an small "slip" oil stone ensuring that no residue is left on the sealing surface that can become engrained into the seal's sealing surface.

One way to install the seal is to use the flanged face securing screw holes, but this would require a circular piece to be machined up and drilled to create a seal pusher. Initial alignment could be achieved and then the seal can be pushed in by small increments on the set bolts.

Tails 1990 928S4 Auto

RyanPerrella

Rob,

Ive finished my new new RMS install and so far the cars been run for probably an hour or more and no drips. (as of yet, KNOCK WOOD)

I swear the seal i got from Roger thats in the car now is exactly the same as the seal i pulled out from the rebuild kit. But for whatever reason it failed. I think you really need to pay special attention to the crank itself and really wipe it down, run your fingers over it a bunch and clean it up real nice the get a good bit of oil on it for the initial wear in.

Rob Edwards

I'm sure that whatever Greg did in terms of crank prep/cleaning/lubing before he installed my RMS will be sufficient. I went for an extended drive last night after driving back from Anaheim and the bellhousing is dry.

That's good info, Tails, I would never have thought of that- Sometimes one's gotta recognize that some jobs are better left to the pros. Perhaps I've just been lucky on all my own work on this beast so far......

GregBBRD

Rob:

We didn't talk about your rear seal, did we? We took a small file and removed the little burrs that were on the end of the crankshaft. We then took an old piece of Scotchbrite and removed the "dirt"/old oil/debris" that was on the crankshaft, in the area where the seal actually touches. We use an "old piece" of Scotchbrite, since an old piece "sheds" less. We then wipe out the area, carefully. This is followed by a complete rinse with your favorite spray cleaning chemical. I started using the factory high pressure grease years ago (comes in the little, expensive white tube from Porsche) on all my seals, where they touch the item being sealed. I actually just "pack" the ridge and groove full. This pretty much eliminated any and all leaking. I seldon have seal issues, anymore....actually can't remember a seal that has leaked, lately. Maybe the seals are better, maybe it's the grease. I have no idea. I just know that I almost never have issues, so I'll keep doing it the same way.

RyanPerrella

Greg,

Thanks for sharing some of your trade secrets. I would hope other people can see this and use some of your suggestions.

Great info

Thanks