rough day with the alternator

[tmblackflag]

I took the old alt off, found a crack in my stock magnesium alternator housing. Got that fixed at a local welder and the job looks good.

The new alternator wouldn't easily slide into the housing because i couldn't get the bolts pointing all perfectly straight up. A couple of them were bent slightly out of the box. After struggling to get all six bolts lined and pulled entirely into the alternator housing (there were about halfway at this point), I decided to put the nuts on the 3 that weren't part of that backside air duct.

I slowly tightened them attempting to bring them the rest of the way through, and stripped one or two of them in the process. Not only are some of the bolts stripped, but the threads between the bottom and top of the alternator that the bolts run through are stripped as well. I can get new bolts with washers that I hope will fix the issue. I'm thinking that as long as i have access to the back bolt with a wrench while i tighten the nut on the top I'm fine. But then I'm left with what seems to be the impossible task of getting the 3 nuts for the air duct back on while the alternator is in the car.

Because the bolt pass-way thread is stripped in a spot or two, tightening the nuts just causes the bolt to spin and I don't have access to hold the bolt heads on the back. The fan is in the way, and if i leave the fan off and try to attach it after all 6 nuts are tightened then i can't fish the fan back on. It needs to go on first while the alternator is out of the car.

What is the trick to these three bolts, even if i hadn't stripped them? It seems they'll spin regardless while tightening the three nuts for the air duct. Do i just need to get a new alternator and be way more cautious getting the bolts through the housing?

[pete3799]

If the mounting studs on the back of the alt. were bent in shipping it's likely the threads were messed up too. I'd source new through bolts and nuts and start again. The nuts that hold the fan diffuser on are tough to get at but doable without having to hold the other end of the bolt.
Where did you get your new alt.? My new one (Valeo) came from pelican and it was packaged so well i think i would survive a drop from a passing aircraft.

[tmblackflag]

New alt was a bosch refurb from Pelican.

I can get to the three nuts for the fan diffuser but i suspect i wont be able to tighten them enough without being able to get a wrench on the bolt head which is impossible with the fan in there.

HOPEFULLY new bolts is all I need and the threads inside the alternator that the bolts pass through isn't ruined as well.

[pete3799]

If the treads are bad cut the end of the bolt off before you unscrew it so you don't wind the bad threads down through the alt.

[tmblackflag]

Too late i have already backed the bolts out. If the threads are bad i believe it is 1, maybe 2 of them. Where would i go to get them re-threaded?

[Porchcar guy]

They make sets of taps and dies to chase threads. Buy a metric set.

[304065]

And don't get any metal chips inside the alternator or it will be fireworks time.

I feel your pain- most important step is to remember to disconnect the battery before doing any work, otherwise you'll have an 800 amp arc welder back there that can kill you.

Second most important step is to have enough slack on the wiring harness so you can put the fan/alternator assembly on the crossmember, run the harness and ground wire through the airguide, put the airguide on the back, put lock nuts on the alternator bolts and then put the whole thing under the fiberglass shroud. Be sure to tape a towel or something in place over the crossmember so it doesn't scratch or dent when the alternator sits on it. BTDT.

[tmblackflag]

Two of six of the alternator bolt openings were stripped. I got a drill bit and threaded them from 5mm to 6mm.

I've got the alternator in the housing now, still took a bunch of banging with wood blocks to get the six bolts into the alternator housing. I had less room with thicker bolts and i swear even with new bolts they still don't line up perfectly. I had to slightly bend a couple of them, otherwise the threads in the tips of the bolts get caught sideways on the housing and it won't clamp down all the way.

When i walked out of the hardware store today they forgot to give me self-locking nuts with the new 6mm bolts. I found some regular nuts at Home Depot though. Will these work alone or do they need washers too? Or do I need the taller self locking nuts?

I'm going to finish off this disaster tomorrow.

[winders]

Maybe you should stop now before you do any more damage......

[Driver_X]

Something is not right here I can change my alternator in less than an hour start to finish. You might have a bad alt, or a damaged housing. Post some pics