TheSamba.com :: View topic - Removing a stuck flywheel bolt the hard way (happy ending).

Sun Nov 23, 2008 8:20 am

I'm replacing the main flywheel seal on my 255Kmi '87 Syncro due to an oil leak.
I pulled the trans and the flywheel bolts were stuck so tight that my nice IR impact gun didn't touch any of them

I got 1 of the 5 hex bolts out after some heat and application of a 2.5 foot breaker bar. I was very surprised not to see any evidence of thread locker, some gorilla must have really nailed these bolts in hard. More heat, some good whacks with the hand sledge and a week of penetrating fluid later, 3 of the remaining 4 were out.

The last hex bolt simply wouldn't turn and as I put more torque on it, I feel it stripping internally, in spite of being very careful and using good tools. The hex head was shot and wasn't coming out. This bad job just got worse.

I ground a notch in the hex head and whacked it hard with a chisel and a 10lb hand sledge. Nothing...

Having no choices left, I resigned myself to having to grind/drill out the bolt and probably messing up the threads in the crank, since I'm underneath, working on my back, with the engine still in the van and the drilling would be done free hand.

I ground the hex head most of the way off with a high-speed fiber disk on an air grinder in about 20 minutes so I could get the flywheel off and out of the way. When the ground-down hexbolt head was nearing paper thin, I lightly put a chisel to it to lift the remains off the flywheel face so I could grind these lasts bits of the hex head totally away and remove the flywheel. At that point, I was mentally figuring that once the flywheel was off, I still had about another hour of hard labor ahead of me to grind the bolt stub flat with the crank end, drill and extract the bolt, and retap the crank threads if they got damaged.

To my absolute surprise, when I tapped the chisel, the ground-down hex bolt turned! In fact, it was finger loose now. I couldn't believe it. The head must have been what was locking the bolt in place, not the threads.

I removed the bolt, pulled the flywheel, then went in, cleaned up and totally enjoyed that extra hour of relaxation that had been added back to my life...

Next step, go over the end-play & main-seal setting resources one more time:
- http://www.gowesty.com/library_article.php?id=535
- http://www.thesamba.com/vw/forum/viewtopic.php?t=266554&highlight=endplay
- http://www.bostig.com/files/bostonbob&bostig-proper_wbxflywheel_install.wmv

Easy flywheel locking hint: I accidentally found a good way to keep the flywheel from turning when putting a lot of torque on the flywheel bolts. I was looking for a flywheel locker like bostonbob uses in the above video and couldn't locate one locally. I was using a prybar backed up by an engine case stud to jam the flywheel teeth, but I needed three hands to work everything and I only have 2. As I was turning the flywheel to a new position, it unexpectedly locked up and I noticed that some of the excess links of the chain I was using to suspend the front of the engine were hanging down and had caught on one of the clutch bolts on the outer rim of the flywheel and were holding it in place. Perfect, I used this chain-to-clutchbolt trick to remove the rest of the flywheel bolts. Being paranoid, I also keep a stout jack under the engine in case the suspension rig failed.

Sun Nov 23, 2008 12:59 pm

You really need to check the sealing flange on the back of the flywheel. Often there is a groove worn into the surface by the old seal, and it will prevent the new one from making a consistent seal. Sometimes they will just leak all the time, but some are especially frustrating because they leak one day, and stop the next. Drives you crazy.

Anyway some of the grooves are shallow enough that they can be sanded and polished away, others are too deep and only a new FW is going to offer even the possibility of a good seal. I would say the groove is shallow enough to polish out if you drag a fingernail across it and your nail just nicks it, but won't hang up in it. If you can lodge your nail into the groove where you can make it stay there, then it's already too deep. This measurement is obviously pretty subjective, so the real proof is whether the groove polishes out or not.

You'll need a way to spin the FW on its center (I use an old crankshaft set in V-blocks; you'll have to improvise), and sandpapers in progressive grits, from 80 or 150 all the way up to at least 800, but 1000 or 1200 do a better job. I douse the flange with WD40, and wipe off and douse it again in between grit changes. You have to spin the FW while working the flange with the coarsest grit until the groove disappears. Then work each successive grit, finer and finer, until you have a really smooth surface left. You could even use some polishing compound on it for the final finish.

If you can get the groove sanded out and take it to a real nice, shiny finish, then you have a really good chance of getting the kind of perfect, dry seal you hope to end up with. Using only the best quality mainseal is equally important, but I've been over and over this and the whole package has to be right; a $30 mainseal will still leak on a grooved FW.