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1982 240DL B21F-MPG
Don't know what happened, but it left it loose at one time, maybe ended up with damaged bolt threads. I tightened it a month or so ago, and noticed yesterday that the alternator belts were loose. Took things apart and had that sinking sensation as half a bolt was attached to the upper alternator slider (the one that goes through the bushing into the block).
If you've ever seen Monty Python and the Holy Grail, where the king is explaining how he "Built a castle, and it sank into the swap. So I built another castle and it sank into the swamp too. Then I built a third castle, it burned up, fell down, then sank into the swamp..."
I tried the left hand drill bit hoping that the bolt would spin out as I drilled it. No luck. Then I tried a tap like thread extractor (*because easy-outs break off all the time*). Know what? They break off too. Center punched the remains of the thread extractor a few times, started drilling into it, realized too late I was off center and mangling the block threads. My last heroic attempt was the helicoil route. I drilled a 21/64" hole into the block, no problems. Next the helicoil tap went in. Just as it was starting to thread in nicely, it bound up somewhat. I backed off, went forward again for another bite, applied a little more pressure and IT BROKE TOO!!! Disaster!
There's a good piece of the tap threads hanging out, but I think I'm going to pay the pros to clean up the mess I've made.
Here's a question for you all: On the block, right above the alternator bolt hole, theres a threaded plug going into the block, with a square keyed opening. Anybody know what it's for? Someone say it's the emergency backup alternator mounting hole!
Greg
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Was able to remove the piece of tap by snapping it with a spring loaded center punch counter clockwise until it was out. Retapped the hole I started and put a proper grade 8 stud in there. Everything is back together and running fine.
Thanks everyone - that was close...
Greg
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That plug screws in to the oil port. I wouldn't use that location to mount the alternator.
steve
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You can try this, and it works! You'll need someone with either an ARC (Stick) or MIG welder, but such folks are more plentiful than you might imagine.
This all has to happen fast and smooth. You are going to have a bolt welded on, lubricate the old threads, and extract the "stub".
1. Grind off all the crap sticking out of the bolt ( the guy who has the welder will have a 3 1/2" angle grinder...trust me).
2. Have a wax candle ready, unlit (not kidding).
3. Quick-weld a bolt right to your sheared off bolt (probably two or three tack welds to it). I'd guess a 5/16 x 1" bolt by looking at your picture. Be sure you have a box end wrench handy that fits this bolt...no time to fumble or go looking for one once this drill begins.
4. Jam candle onto the bolt/block interface all around the bolt. It will melt rapidly from the heat, and actually wick into the threads.
5. Using the newly welded on bolt head, take a wrench and turn it out of the block.
The heat of the welding opened up the gap between the bolt and the block, the wax lets it get going even better than the legendary PB Blaster, which I always have right there next to my Aerokroil on my shelf. The newly welded on bolt gave you a way to get ahold of the old one enough to twist it out. IF the trick didn't work (and I would be very suprised at that), have the welder guy (who by now is determined that the DAMN BOLT is COMING OUT!! DAMMIT!) cut the bolt, gring flush again, now weld another bolt head side to the stub, and you now have a mounting stud for the alternator!
Don't worry...home hobbyist welder types love the challenges of doing this sort of thing, and both of you will have learned a new trick! Be sure to have a cold 12 pack in the cooler to force upon him AFTERWARDS, and a $20.00 to "pay for materials" won't hurt, either.
It can be done, and you can do it!! Step forward into the nordic wind and face the challenge, Volvo Man!! (Viking Horns play at this point).
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Fantastic post - great ideas!
I like your last ditch suggestion of welding a bolt head side to the block as a mounting stud for the tiedown pivot.
Pretty alarming to go from a well running '82 brick with less than 130k miles to a donator car. Hopefully we'll avoid that...
Greg
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Hopefully this message should have a picture from the board's gallery attached:
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eeee gad, dont you just love that case hardend stuff.
if it were i, i would start looking for a fabricator who could design ans alternate,,, alternator bracket of some kind, or see what kind of stuff i could fabricate one myself at a boneyard, or maybe a skilled welder could heat up the surrounding metal and possibly get that tap remains out.
the thread hole plug abouve might searve as an alternate location for a bracket good luck.
--
never snort horseradish
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Well that's what you get for drilling SAE bolt threads into a European engine block! Ah, seriously that scenario is much too familiar and whoever you take it to is going to hate the job. Best bet at this point if it's not done already may be to remove the radiator and AC condenser so there's better straight-on access to that thing.
At this point it really doesn't matter what size bolt is used, so any old bolt can be tapped in there, cut off, and then redrilled and tapped for the correct size and location. Hopefully it will cost less than a new block!
Good luck!
--
Rob Bareiss, New London CT ::: '87 244DL/M47- 230K, 88 744GLE- 220K, 82 245T-181K Also responsible for the care and feeding of: 88 745GLE, 231K, 87 244DL, 239K, 94 855GLT 189K
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Thanks for the advice - I'm going to look into that upper plug and see if I might be able to work something out to replace the mess I made below.
To install a metric 8.8 helicoil you drill a 21/64" hole. I guess the rest of the world always grins when the see us fumbling with our fractions of inches...
Greg
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