Otto Mechanic

I almost declared getting the clutch housing off of an '89 944 S2 when I was stuck again by two bolts that aren't shown anywhere I can find in the '91 PET but are mentioned in the WSM procedure in step 2 of "Removing and installing the Clutch".

The WSM says "remove two socket head bolts". They're shown in the attached photo, mislabeled as "Hex Bolts", should be "Hex Socket Head Bolts", but they're difficult to reach and I can't find the size of the hex key needed for the bolts. Does anyone know either the dimensions on these bolts and/or where to find them in the PET? They don't seem to show up on the clutch assembly drawings, or in any torque tables I can find.

Hints on the best way to reach these bolts would also be appreciated. The manual suggests removing the air cleaner. I'm not well versed with these cars, but as far as I can tell the "air cleaner" is on the front of the engine near the hood latch? I can't see how this would help?

Otto Mechanic

While I'm at it, does anyone know what Porsche calls the "speed" and "reference" sensors? I can't find a single part with the word "sensor" attached to it in the '91 PET that also has either "speed" or "reference" associated with, or on a page that looks like it has anything to do with the clutch housing.

What are these things really?

Otto Mechanic

Well, the answer is they called "pulse senders" not "reference" or " speed" sensors in the PET. They're under engine electrics and are shown with the DME. The assembly used on the S2 apparently isn't used on earlier models with two of these senders (the S2 only has one). There doesn't appear to be a mounting block for the senders, the holes look like they're molded into the bell housing?

So I don't think the manual is going to be of any help.

If anyone has experience removing the clutch housing on an S2 and can verify that these socket head bolts need to be removed, what size they are if they do, and give some advice on the best approach to them I'd certainly be all ears

mikey_audiogeek

Can't recall what I did when I changed my clutch, but the Clark's Garage manuals were pretty accurate.
Did you read their procedure?
Cheers,
Mike

FRporscheman

That year has the extra aluminum sleeve that shields one (or both?) sensors. So essentially, even though you have pulled the sensors out, it doesn't help, because the bell housing will get caught on the sleeve.

Remove those two allen bolts. They located in illustration 901-05 (a few pages into the Electrical section). They are items number 14 and 15: M8x25 and M8x30 pan-head screws (aka allen bolts).

Note that the bracket pivots on a roll pin, through which the shorter bolt goes (the bolt more to the driver side) so once the bolts are out, gently pry the bracket off of the roll pin.

When reinstalling, you will need to follow the procedure to re-set the gap for the speed and reference sensors (by pivoting this bracket).

The torque on any M8 bolt threading into aluminum is 15 ft-lb unless otherwise stated.

They take a 6mm allen wrench. I've only had to remove that bracket once (with the engine in the car, that is), and I remember it was a pain in the bitch, and I was only able to use an allen wrench, not a socket.

FRporscheman

Oh yeah, and before putting the bellhousing back on, do the "notch mod." Do a search on "notched bellhousing" or something, you'll find it.

Arominus

The notch mod can cause misfires at startup if you don't put that shield back on the Ref sensor though, the shield prevents magnetic interference from the starter. Im fairly sure this is why the 968 engine in my S2 kicks back when its attempting to start. The shop that swapped the motor likely notched and did not re-use the sleeve.

IIRC the 16v cars have one speed/ref sensor along with the cam sensor where the 2.5/turbo cars use 2 seperate speed/ ref sensors. The air cleaner they likely reference is for the "S" which had the throttle body back in that area.

Otto Mechanic

The thing that confuses me is the PET shows that sleeve/shield as a separate part, seems like I should be able to pull it out without removing those two bolts and the block it's mounted into?

If these bolts are torqued to 15 lbs. I'm a 98 lb weakling. I have 6mm socket on the top one with an 8 inch wrench on it and I can't break it loose for love or money. Soaking it in PB Blaster now...

Otto Mechanic

Now I understand why people notch the clutch housing.

Otto Mechanic

BTW, the best tool setup I've found so far is:

6mm 3/8 allen socket, shortest you can find
3/8 socket cap
14mm or 3/8 gear wrench

Socket cap goes in the gear wrench, socket on socket cap. This setup is thin enough to clear in the space provided by Porsche (sarcasm intended) and longer (more leverage) than a standard allen key. I wish I could get a 3/8 breaker bar on it but there's an aluminum line on the firewall that won't give me a straight line on the bolt head with a longer wrench. May try a universal if the PB doesn't work.

Otto Mechanic

So after discovering the correct procedure I got the bolts out in about 20 minutes using the tool described above.

Now I have a difficult decision to make. It appears this may be one of the great secrets of 944 clutch repair. Shall I reveal the technique that so many seem to dread and leads to modifying the housing, or would I be betraying the Illuminati? I don't want to bring down the wrath of that secretive and powerful order...

Dimi 944

Glad you succeeded. My secret was dropping the engine. It is actually faster than fighting all the way through the process as it is on the car.

Otto Mechanic

Unfortunately successfully removing the sensor holder hasn't solved my problem. The clutch housing now rotates free within the confines of the tunnel, and moves in and out about an inch, then binds on something and won't move any further. I have applied moderate force in equal amounts around the housing but she's good an stuck.

There aren't any bolts or parts left to remove. This is clearly another mystery.

Otto Mechanic

It's only success on a sub goal, getting the pulse sender holder out. Even that has tricks to it that aren't mentioned in the guides, fortunately there's YouTube video I watched the other day that explains how to do it right and the consequences of doing it wrong so that was simple. The video doesn't discuss how to get the bolts out, just how to get the holder out once you have.

I'm stuck now. No idea what's keeping the cover on. It moves back and forth about an inch all the way around and rotates freely but it won't come all the way off.

It must be binding on something internal, I just can't figure out what, or how to free it.

Dimi 944

Hm...that really sounds like the clutch fork is still in place.