RallyJon

Belts have been squealing recently, so I figured I'd do them some time in the indeterminate future. Today I noticed that the alternator belt has a nice mm deep wear mark on it! Sure enough the tension sensor pully has seized solid. Can't turn it by hand at all, so I'm not optimistic that a bit of WD40 will make it new again.

So I'm about to order parts, and I have a few questions:

1) Even though I have a '95, can I use the "97+ sensor 993-106-035-00? It looks like it superceded? Any change in mounting or add'l hardware needed?

2) The DIY on Robin's site suggests that a different belt is needed with the pulley update, but it's not clear if that's for all engine versions. Do I get the 753mm or the normal 760mm belt? Edit: covered in TSB linked below: shorter belt is Turbo only.

3) What about shims? Should I order extras just in case or can I be sure that whatever is on there now can be reused and will provide enough shimming?

4) Anyone have the updated pulley halves TSB? Edit: found it http://www.993faq.com/archives/cat_engine.html#000129

Thanks! -Jon

epj993

Jon,
My PET CD shows the 993-106-035-00 sensor for all model years. On the shims, my guess is the ones you have are probably enough as the pulley update only eliminated the sleeves on the outsides of the pulley (IIRC).

RallyJon

Thanks. Gotta love Porsches: belts = $38.75 total, other crap to do belts = $163.50.

RallyJon

One more question: the old belt tension sensor roller was not centered on the belt--it was about half on and half off, toward the rear of the car. I installed the new sensor and it's the same. I checked the belts/pulleys and they seem perfectly aligned. There's no room move the sensor closer to the engine, since the fan is in the way. The only way to get it centered would be to shim the pulleys rearward somehow. Odd.

Is this normal?

epj993

Jon, my sensor is positioned more to the back side (toward engine) with the entire wheel riding on the belt. From the diagram below, there's a spacer sleeve (#17) that should be behind the first pulley. If it was missing, the pulleys would be closer to the engine. However, if this were the case I would think that the belts would not be in alignment.

Just a thought...

(BTW, this diagram shows the pre-updated pulley)

chris walrod

Very typical!!

geolab

posted this earlier, here is the tsb
.
.

RallyJon

OK, thanks.

Saw the TSB, and I do have the new belts pulley halves (waiting on the triple square tool). But the sensor roller is on the fan belt, not the alternator belt. Even if the alternator pulley had some strange shim arrangement, it wouldn't affect the fan belt alignment, right?

geolab

right.
I hate the triple square tool as you call it. Do a search and see why I hate it, of course it is a personal opinion.

geolab

here, this was my personnal opinion, and still is:
"in my tiny experience, I have seen dead threads in alternator shafts that looked sooo ugly, that even
after purchasing the porsche tool, I refrained from using it.
Instead, I purchased the central nut plus the three 6-pan screws holding the middle pulley for $2 at the dealer.
I removed the Big central nut with a chisel and a small hammer. One small tap with the chisel at 11 o'clock on the nut
and it comes loose.
later, two out of the three 6-pan screws came out easy, but the third took a chisel blow as well.
installed the new ones when mounting. cost, $2." The porsche tool used only for tightening.
This way I was 100% sure that I wouldn't risk a stripped shaft.

RallyJon

Did you split the nut, or was one small tap enough to loosen it? If one small tap loosened it, wouldn't more conventional methods have worked too?

With the the screws, what happens when you chisel the head off? Then you have a bigger problem getting the rest of it out, right?

geolab

A small tap on 11 o'clock with a 1.5/2 lbs. chisel, parallel to the axle for the nut.
As for the screws, basically the same proceedure for the nut, but you have to create a groove by tapping a small tap vertically as if at 12 o'clock, and then place the chisel in this groove and tap at 11 o'clock to loosen.

we are loosening here, we are not chopping the head off.
the chisel head should be parallel to the alternator shaft with all, not perpendicular.

As for the porsche torx tool, you sometimes think the nut is going to loosen when you realize your shaft is stripped.
The engine crank moves the pulleys clockwise as the alternator shaft outside threads.
This action tightens the nut, and some are really hard to remove.
If there is a DIY by Robin for a stripped shaft, is that probably it is common to strip it.
I am not being a smart guy. This is my honest opinion and how I personally do it on my car.
A new nut and six-pan screws cost me $2 each time I purchase belts from the dealer.
cost for the nut and screws $2
cost of changing a stripped alternator shaft, I will let you guess...
just my .002cts.

RallyJon

Understood. It would be a disaster to strip the shaft in my driveway.

RallyJon

Big thank you to geolab! Even with the correct tool, it was clear that the shaft would strip before the nut came loose. I used a combination of PB Blaster and a small torch over about an hour, but ultimately a whack with a chisel broke it free.

The three screws holding on the fan pulley were corroded looking, but came out easily.

The surprise problem was the A/C compressor belt tension screw (under the compressor). It was frozen in the aluminum base. Luckily, the base is a separate piece and I could remove it and use a torch to heat the aluminum a bit and get the screw loose.