Alt Belt replacement
 

Does any 964 member know of a "trick" to loosen/remove the 24mm nut on the alternator shaft other than using the special Porsche polygon wrench (which is not in my tool crib)? I can only imagine the frustration if you are on a road trip and a belt fails, have back up belts in the trunk and no Porsche polygon wrench. Hence the need for a trick.

you can buy a star bit at most auto stores to hold the shaft. I got one at NAPA but had to cut it shorter to get it to fit in the short space. I just hold it with vice grips and put the wrench to the nut.

I can only imagine the frustration if you are on a road trip and a belt fails, have back up belts in the trunk and no Porsche polygon wrench. Hence the need for a trick.

The trick is this: Jack one of the rear wheels off the ground, put the car in 1st gear. Place the new belt around crank pulley and as far around alternator pulley as possible, then one person eases the wheel forward thus turning the crankshaft pulley while person 2 eases the belt up and over onto the pulley with a large flat screwdriver. Takes 20 seconds. Ask me how I know.. :)

Alex

The factory tool kit has the tools needed to change the belt. Both are standard tools.

:confused: Huh? Please elucidate.

Here's what I encountered:
The alternator pulley's 24mm hex nut cinches the alt's pulley onto the alternator shaft.
The alternator shaft's end is broached for a 12-pt 10mm 'star' (or, aka, a "triple-square") drive bit.
The 12-pt bit is used to counter-tighten/loosen against the 24mm nut.

From my experience, the tool kit (at least in '93) sure doesn't have anything like that alternator shaft's required 10mm 12-pt bit in its contents.
(Ref. Keith V's page, here.)
Absent heroic McGyverisms, you Willl be left stranded given a broke fan or alt. belt.

Like Jim, I had to track down that 12-pt. at a local NAPA store. (...the THIRD store finally had one in stock.) :rolleyes:
Without that 10mm 12-pt (on a '93, at least), you aren't changing those belts - unless that 24mm hex nut is spooky-loose to begin with.

(I'm putting together a little pictorial re this whole assembly as an adjunct to MrRisky's infamous RS hub video. A "how to" for installing an RS fan hub if your fan bearing, unlike MrRisky's, is still working fine.)

Alt Belt replacement Update w/Pics
 

Update.
Took the advise from last post and went to the tool store and purchased a set of 12 point star bits, 6, 8, 10, 12mm.

The 10mm is too large, the 8mm is too small. So the job is not yet done. I would GUESS that a 9mm is the size (I hate guessing). Nonetheless I went shopping of a 9mm 12 point star bit. Almost "unobtainium" (have yet to find one).
I have posted 2 pic of the alt shaft with 24mm nut. it seems to me...
a) the broached hole isnt really for a star bit
b) the 24 mm nut has stamped "9.0" (between the 12 and 1 o'clock positions), what does the represent?
c) Any alternate solutions (sorry for the pun)

Thanks
rod911964

The 10mm triple square from Snap-On should do the trick. I just bought one but haven't had a chance to do this yet. According to others it's perfect.

Here's a thread on this from across the street: https://rennlist.com/forums/993-foru...placement.html

10mm is what the size is. It looks like someone forced something into your shaft messing the spline up.

Looks like someone has used a six-sided hex bit instead of a 12pt star bit, hence the hole is buggered up. Take it to a professional; they deal with problems like all the time.

I added a mini Craftsman adjustable wrench for the 24mm duty, and have the Porsche triple square in my tool kit. I've never had to do a roadside belt change, but the Porsche tool works fine in the garage. I use a proper 24mm wrench in the garage, but I've tested the adjustable and it will work if necessary.

Someone buggered the end of your shaft......but it doesn't look too bad. They used an either a easy out or Torx on it, whatever.

I would slightly ground down the high points on your 10mm triple square... taper it too...maybe it will fit then.

Someone buggered the end of your shaft......but it doesn't look too bad. They used an either a easy out or Torx on it, whatever.

I would slightly ground down the high points on your 10mm triple square... taper it too...maybe it will fit then.

Yup, someone ham-fisted the job in the past. :surr:

Here's what an unabused (yet spec-rusty!) shaft end looks like: (Minus the alternator belt, alternator pulley halves, pulley shims, nut, and outer washer):

Attachment 454167

Aftermarket tools to do the job:

Attachment 454168

Tools happily at work, taking off that alternator pulley nut.
To loosen; big wrench goes CCW, little wrench goes CW
(Optional: surrounding job with Bosch boxes for good luck.):

Attachment 454169

Ugh...frustration!
Well I ordered and recieved a Snap-On 10mm triple square bit. Its a No-Go! See pics below. It's just too large. Seems very odd to me if the prior owner buggered it up, the hole would be larger not smaller (duh). As mentioned befor a 10mm is too large, 8mm to small. My thoughts now are to...
1) Take it to a professional
2) Try to find a 9mm tool
3) Cut a slot into the shaft to place a cross blade to hold in place

Any other thought/reccommendations

Thanks
Rod911964

Pro.

(And, perhaps, install a new/refurbished alternator when things come loose?
I know, I know... why throw out the baby with this bathwater?
A: Because sometimes things need replacing, anyways.) :(