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Old 12-28-2007, 09:34 PM   #1
Rob Edwards
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Default Removing tenacious rear main seal?

Feel free to toll your eyes, most people have trouble getting their RMS back in, I can't even get the old one out. I tried prying under the edge of the RMS in the groove at 8 o-clock- no go. Then I gently wedged a 90 degree hook into the side in the groove and tore the rubber coating a little. I recall reading on some BMW site about drilling a hole into the RMS and screwing a screw in a turn or two. I pulled the screw out of the hole. Then I stuck the tip of the 90o hook in the hole, yanked on it, and broke it off, so it's stuck behind the RMS now. So I'm committed to getting this bastard out. And it's now seeping oil down and onto my oil pan. And I'm afraid to jack on it too much for fear of slipping and scratching the crank.

I have the clutch assembly and the TT out, so I have all the room in the world, relatively speaking. I recall seeing a picture of someone's RMS post-removal with strips of rubber still attached, maybe I just need to run a blade around the outer circumference? Is the 'sealing' done entriely around the crank (ie- if I scratch the block where the outer edge of the RMS sits, is that a disaster?) If not, can I either A) hammer the screwdriver under the outer lip in the groove, or B) dremel thru the outer rim of the RMS and break the tension of the ring, a la removing flappy bearings?

My apologies to all the real mechanics who are probably shaking their heads....

Suggestions/tips/hints?

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1993 928GTS Midnight Blue/Light Gray, C02 058 130 139 218 239 323 340 403 418 423 437 438 464 474 481 484 537 553 562 567 570 573 586 595 602 650 691 912 980 XD4 XGB65 105K mi

1988 S4 5-speed, White/White, C03 158 220 418 474 481 494 513 538 570 586 650 91K mi

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928 Option Codes List, Current as of October 2013 Here: https://webfiles.uci.edu/redwards/pu...2010-7-13.xlsx
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Old 12-28-2007, 09:43 PM   #2
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its a pain in the *** in the car.

3 days ago i finally pressed the new seal in, but i havent been bothered to get back under the car and put the flywheel back in cause i am kinda burnt out at the moment

I would suggest the drilling tip, but maybe you need to just try and find something else to use to pry the thing out. I pulled my seal and it was a pain but getting it back in was a bigger PITA,

To install use the old seal, plus the new seal and get longer then stock bolts for the flywheel and use the flywheel and the old seal to press the new one in. When its seated, remove the bolts (3 or 4) remove the old seal thats used as a shim and then fully seat the new seal and reinstall the flywheel using the correct bolts.
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Old 12-28-2007, 09:56 PM   #3
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explosives




Actually I punch a hole and grab with a bent pick of sorts... i heat bent a screwdriver. Be careful, the aluminium there is very soft Rob
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Old 12-28-2007, 10:02 PM   #4
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Just take a big screw driver( long handle) , place it in the groove, smack the end with a hammer a couple of time to get the screw driver in there and pry it out. If you can get a bit of an angle on it to get under it some that would be better, but it should pop out. You just want to disfigure the seal a bit to create a gap around the edge by the groove. It'll come out, just don't ***** around with it. Of course be carefull you don't drive the screw drive into the crank shaft.
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Old 12-28-2007, 10:10 PM   #5
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Keith I personally am a big believer in *****. Especially around thin oil galleys....
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Old 12-28-2007, 10:37 PM   #6
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take a fairly thin (cant be too thin) flat head screw driver, file or sand all edges/surfaces to remove really abrasive marks, and slide it between the crank and the seal.
Do not put it between the block and the seal.

This will get you under the metal part of it, move the handle of the screwdriver towards the opposite side of the crankshaft.
This will give you leverage and it will come out fairly easily.
Keep in mind it will probably deform the seal slightly on exit which is fine.
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Old 12-28-2007, 10:42 PM   #7
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gr8 idea
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Old 12-28-2007, 10:42 PM   #8
Rob Edwards
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Well, she's out.

Take THAT, beyotch!

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Couple of big hits with the BFH, and the old seal buckled. Took about 60 seconds.

The bad news is that I must have made a little ding on the edge of the crank while pissing with my screw or hook:

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It's right on that diagonal surface, it's not on the swept surface of the crank, so am I ok if I just emery paper the edge so it doesn't tear the new seal on its way in?

The RMS did manage to extract a lb o' flesh while I was messing with the hook:

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Nice view:

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1993 928GTS Midnight Blue/Light Gray, C02 058 130 139 218 239 323 340 403 418 423 437 438 464 474 481 484 537 553 562 567 570 573 586 595 602 650 691 912 980 XD4 XGB65 105K mi

1988 S4 5-speed, White/White, C03 158 220 418 474 481 494 513 538 570 586 650 91K mi

"A gentleman does not motor about after dark"
Joseph Lucas, 1923

928 Option Codes List, Current as of October 2013 Here: https://webfiles.uci.edu/redwards/pu...2010-7-13.xlsx
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Old 12-28-2007, 10:48 PM   #9
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yeah that is a neat view, it took me a minute to figure where the hell that was. Obviously your TT is out.

How did you find rebuilding the TT? Dont you need to make some type of giant press to get those bearings in and out?
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Old 12-29-2007, 12:23 AM   #10
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Good job...should have waited a little bit to read our advice and you could have saved some trouble. Glad you got it out...didn't ***** it!

Anyway, just tell your friends you got bit by a shark.
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Old 12-29-2007, 12:42 AM   #11
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I used Keith's technique with not so much force as to cause the screwdriver to nick the crank. The seal has a metal core under the rubber, so the goal is to create a small longitudinal dent in seal at the notch area. One or two smacks will do that. Then use the tip of the screwdriver in the notch and lever the seal out with the shaft against the pan edge. It won't move at first, but will begin to work out slowly. The notch was cut ln the block just for this purpose.

Hopefully your nicks are away from the seal area, although it looks close. Dress them using a small emery point/drum and Dremel to make sure the new seal does not catch on them during insertion. Those nicks are deep. I once made some very fine scratches on a motorcycle counter-shaft while extracting the seal and the new seal leaked worse than the old one. It took a lot of work with an emery point to smooth it out and get the new seal not to leak.

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Last edited by Bill Ball; 12-29-2007 at 01:36 AM.
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Old 12-29-2007, 12:57 AM   #12
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Ryan-

Rebuilding the TT was a snap- 5 easy steps:

1. remove old TT
2. Call Jim
3. Drive to Anaheim
4. Transfer shifter bracket, shifter, and re-align.
5. Install new TT.

Bill:

Dumb question- By 'dress', what would you use to smooth that edge of the crank? I have some 2000 grit sandpaper, but I can't find how that compares to crocus cloth or emery paper. Is that ok?
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1993 928GTS Midnight Blue/Light Gray, C02 058 130 139 218 239 323 340 403 418 423 437 438 464 474 481 484 537 553 562 567 570 573 586 595 602 650 691 912 980 XD4 XGB65 105K mi

1988 S4 5-speed, White/White, C03 158 220 418 474 481 494 513 538 570 586 650 91K mi

"A gentleman does not motor about after dark"
Joseph Lucas, 1923

928 Option Codes List, Current as of October 2013 Here: https://webfiles.uci.edu/redwards/pu...2010-7-13.xlsx
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Old 12-29-2007, 01:11 AM   #13
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well thats the $400 method right?

I figured you would have just bought the 3 bearings for $50 and done it yourself. Perhaps it is too much of a pain to get involved in all that
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Old 12-29-2007, 01:19 AM   #14
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Quote:
Originally Posted by Rob Edwards View Post
Bill:

Dumb question- By 'dress', what would you use to smooth that edge of the crank? I have some 2000 grit sandpaper, but I can't find how that compares to crocus cloth or emery paper. Is that ok?
I think emery works best on this metal. Crocus would probably be OK. Just trying to take the edge/burr off. If the nicks are in the sealing area, you've got a problem.
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'87 rear resonators; '83 LSD; PKlamp on TT, Bilsteins, 2002 996 wheels; Momo Club 4 steering wheel; H4 Hi/Lo HID headlights; HID driving lights.

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Old 12-29-2007, 01:22 AM   #15
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if there is no seal or bearing riding on the scuffed area of the crank, you could just leave it alone...? other-wise, emory cloth should do......

--Russ
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Old 12-29-2007, 01:22 AM
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