ChaseN

...and the alternator shaft is stripped. I knew this was coming; I replaced my fan belt when I bought it about 6 years & 40k miles ago (using the correct 12pt 10mm tool) and the shaft appeared "slightly" stripped even then, like a former owner/mech had attempted to use an allen key, but gave up and got the right tool "just" before total strippage (OK, so this isn't a word) occurred. My last job must have did it in though, because now it just rotates inside the shaft when I put any force on the nut, and upon visual inspection, its obvious that there's nothing but a circle left inside the shaft. Damn.

So I got to thinking about what to do. Disassemble everything, pull the whole assembly out and try to finagle it in a bench-vise? Nope, sounds like a pain. Ignore it and hope it goes away? Getting closer . Weld the head of a bolt on the end of the shaft just slightly smaller than the outside diameter of the shaft? Aha. Think I'm gonna take the car to work tomorrow and have one of the welders do it (don't worry, I live less than a klick from work, it won't overheat - plus I even noticed the fan turns at just about full speed with the belt broke anyway, a product of friction between it and the alternator shaft I'm sure). Anybody have any reason I shouldn't do it? Any reasonable alternatives? I wish the fan belt came off the same way as my '74 does, with the big idiot-proof half moon looking wrench that actually locks into the pulley. Any special precautions for welding on the car? All my BMW's I just unplugged the battery to be safe, and it was always fine.

I'll let you all know how the saga unfolds.

elbeee964

Ground out the welder as close as possible to the end of the shaft. Like, on the (upper) pulley

If he grounds out on the alternator body, the ground path would be through brushes and shaft bearings.

The battery stuff I don't know.
But disconnecting sure sounds like a conservative measure.

Further, I'd take this as a BIG, clear sign -- God: "ChaseN! Change your alternator! Soon! As in, NOW!"

Good luck, sir.

ChaseN

Thanks for the tip, I'll make sure he does that.

Heh, actually yesterday when I went to the local import parts house to get a new fan & alternator belt, I told the guy what I needed and he looked at the computer and proudly announced "$199, could have it by Saturday". I was taken aback for just a second (I know about Porsche tax, but c'mon...)...and then realized he misunderstood me and thought I needed an alternator. Perhaps you're right about these signs...

Dave White

Nah, fixed mine that way right after I got the car by having a hardened allen head welded in the hole for the 12 pt. That lasted over 10 years, the only reason I still don't have it as I replaced the alternator while the engine was rebuilt. Just make sure to put the appropriate allen wrench in your tool kit, and a spare belt. Make sure you don't have any play in the alternator bearing while the belt is off, just a good time to check.

ChaseN

Alright well the surgery went successfully, used an old scrap allen key to good effect. What didn't work so well was the fan hub stud I snapped (for some reason my hub has studs & nuts instead of the cap screws I see on most others) while tightening the fan pulley onto the new belt . So I put it all back together without a fan belt on it once again so I could at least get it home from work (I have an awesome job where working on your Porsche at the office is a perfectly normal thing to do ). Guess I've got an excuse to spring for the RS hub.

If it isn't one thing, it's another...

Quadcammer

I would just insert a screwdriver into the fan hub to loosen and tighten everything.

I don't bother with the shaft holding tool.

ChaseN

I'm not really sure how that would work - my shaft was so far gone nothing short of a pair of vice grips would have held it - not to mention how tight the nut was on. At any rate, it's fixed now and is an even better solution IMO than the factory method.

Quadcammer

by inserting the screwdriver, it holds the alternator blades and keeps it from moving, hence you can remove the bolt...how stripped the shaft is makes no difference.

ChaseN

I got you now, I thought you meant you wedged the old flathead into the shaft somehow...couldn't quite make that one work in my head. I'll have to remember that if my recent field repair ever kicks the bucket (on the side of the road if it does, I'm sure...)

bmohr

hold it, i need some clarification as i'm doing my belts now and i don't have the 12 pt tool, just an allen key. What direction/rotation does the 12 pt bolt go to remove? So you just block the blades with a driver, then what? unscrew the main 15/16 nut? Need some advice here.

bmohr

so when I hold the blades and use my 22mm wrench to loosen the bolt all it does is spin the belt i'm scared to mess something up with the ignitiion system turning the pulling counterclockwise.

jimq

you can put rope or something around 2 sides of the belt and twist a screwdriver or something in it thus pulling the belt tighter.

bmohr

ok, got everything taken apart well but ran into trouble with the furthest from me belt. What happened was the two rings weren't parralell. The top gap was fatter due to the belt than the lower portion. I tried using the 3 nuts to adjust and one of the fkers broke off So, first question is will this endanger my operation, how to remove now? Second, I put everything back in order and the car runs well, no noise from belts BUT you can def see the little disturbance on the pulling rings from the gap difference that I noted earlier. Is there a tolerance with this or should there be basically no lateral movement whatsoever? Looks like I'm going to need an indy's help on this one

ChaseN

Mine did the same thing, I put it back together without belt on it and am not driving it until I get a replacement nut/stud. As far as the belt causing a gap in the pulley, what I've done in the past is to "bump" the starter as you tighten it, every little bit you tighten when the starter cranks over it will force the belt to ride a little bit higher. Hope that makes sense.

bmohr

thats good advice Chase, thanks. I"ll try that. Now i have to source a new stud/bolt. Anyone got part numbers on that one? Or replacements for the original? They seem weak


this is the only one i could find on Pelican but it is for a 993 and doens't look like it is the correct bolt

900-119-026-02-M100

http://www.pelicanparts.com/cgi-bin/...7%29%2C%20Each

edit: I found this must be an updated bolt because the original parts diagram shows the bolts as:

Pan-Head Screw - 900-119-026-02