How many ways can you screw up a main seal?

Ozzie · Post by **Ozzie** » Wed May 17, 2006 9:26 am

Short & to the point.
Engine runs good.
Want light flywheel.
Pull engine, pull pres plt, pull "old" flywheel, take out "old" black main seal, replace with new red seal, install new flywheel keeping track of shim location, put everything back together.
Engine in car.
Starts easy, idles good, smoke from new muffler paint burning off.
5 min later, black oil (oil in crankcase clean) drips profusely from seam between eng/trans.
Is this the main seal leaking?
What could I have done wrong?

Bruce2 · Post by **Bruce2** » Wed May 17, 2006 11:52 pm

You forgot to install the O-ring in the flywheel. BTDT.

helowrench · Post by **helowrench** » Thu May 18, 2006 6:24 am

How far did you press the new seal in?
one of the manuals (Bently) leads you to believe it needs to be flush with the case. After 5 yes 5 go-rounds of exactly the same deal, we looked in Muir's and found to push it in until it bottoms out.
Yaeh, 6 total removal/installs, we got some practice that weekend.

Rob

Post by **Marc** » Thu May 18, 2006 8:01 am

You changed flywheels and didn't check/reset the crankshaft endplay? BAD BOY.

Since you've got to take it apart again anyway to install the O-ring, check the endplay first. If it's between .003" and .006" don't sweat it; if it's any less you must go to a thinner shim stack, if it's more it'll need thicker shims but only after you make sure that none of the movement is between the thrust bearing and the case. You'll probably be able to coax the seal out without damaging it but if there's any doubt change it (in other words, don't start the job without a new one handy, you can take it back if you don't use it). Try to find a good OEM-quality O-ring with graphite coating (helps it to slide over the crank without damage)...P/N 311 105 295A.

Is the "new" flywheel brand-new or does it have a wear groove where the seal lip rode in its former life? A virgin surface isn't too picky about how deep the seal is installed, but if there's a groove you can miss it by installing the seal more or less deeply; there are also both single- and double-lip seals available.

Ozzie · Post by **Ozzie** » Mon May 22, 2006 8:00 am

Thanks Guys.
Bruce2, you nailed it. At least I can remember the big pieces. I wonder what BTDT means, but if you are saying I should read more manuals while I'm wrenching, I agree.
helowrench, I love John Muir and don't understand why some people put his work down & cinsider Bentley to be a god. I would have loved to met that man.
Marc, I got your post too late. The mills in. I had two seperate VW mechanics tell me to just be careful with the shims & stack them back the same way. Maybe they need the work. Is there any chance of checking endplay from the pulley end? I do have a Berg steel machined pulley. It's square & true. Could I go off that?

Post by **Marc** » Mon May 22, 2006 8:17 am

Yes, you can check the endplay from either end. Be sure that you're only measuring actual endplay and not any flexing of the pulley (if you're measuring at the pulley rim, pull it back, zero dial indicator, then push forward on the pulley bolt). Or, push the crank all the way forward and zero the indicator, then watch it while an assistant steps on the clutch.

Bruce2 · Post by **Bruce2** » Mon May 22, 2006 12:37 pm

ozzie wrote:... I wonder what BTDT means,...

Been there, done that.

Ozzie · Post by **Ozzie** » Tue May 23, 2006 6:48 am

Bruce2 wrote:
ozzie wrote:... I wonder what BTDT means,...
Been there, done that.

Thanks. At least I have someone to share the pain with.