Fan Belt Change

[AirCooledExcellence]

Hi All,

I'm relatively new to Porsche ownership, and thought for one of my first jobs I'd replace the V belt, Easy!?

Problem is I can't even get the blasted nut off the end of the shaft. I'm using the correct pulley spanner and soaked the nut with some penetrating oil, but no luck!

I was thinking of a little heat on the nut, but wanted to check with you guys that this won't damage the alternator?

Any comments/thoughts would be appreciated!

Thanks.

[Ted Stringer]

Is the problem that the shaft is turning? If so there is a special tool to hold it. It should be in the toolkit that came with the car. The only problem is some people bought cars that don't have their toolkit still with them. I know that I will get preached at about the right tool for the job, but I don't have the tool. I just stuck an 8mm allen key into the end of the alternator shaft and was careful.

I wouldn't use any heat on the nut, its probably just croaded (spelling) onto the shaft.

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Ted Stringer
nuke3@juno.com
'84 911 Targa aka pocketrocket

[Early_S_Man]

Sometimes it takes an impact wrench to get that alternator shaft nut loose ... because that may be what the last idiot used to tighten it with!

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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[Jim T]

Make sure you know exactly what you are doing with the shims. You need to use all 6 or 7 of them (some on the inside, some on the outside). If all 6 or 7 of them are not there, somewhere, you will shortly end up with a trashed fan. Not cheap.

[cary]

Did you get it off yet ?

If you don't have access to an impact wrench.
Put a long pipe on your socket wrench. Have someone hold the pulley spanner. And "slowly" loosen it.

Heed Jim's warning. Use all the shims. Should be 1/2" defelection.

Good Luck

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Cary Kutter
77 Euro Carrera w/3.2
74 914 2.0 ( base model )
PCA Region - Big Sky

[Eric Coffey]

Just be carefull when you get the nut off. The outer pully half will want to come right off, and you don't want to lose any shims down by the crank.

-Eric

[Superman]

Put the engine in gear with the e-brake on. Pinch the two belt strands together between the pulleys, using a zip tie or something. Additionally use the spanner to hold the engine. Use a long-handled tool for the socket (breaker bar, ratchet with cheater-pipe). That'll do it. Air tools are for sissies.

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'83 SC

[Early_S_Man]

Unless, of course ... the fan belt broke!

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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[Doug Zielke]

Actually, Super, air tools are for guys with a compressor! (Want me to bring mine along?)

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'81 SC Coupe (aka: "Blue Bomber")
Member: SCWDP
Canada West Region PCA
The Blue Bomber's Website
"If it ain't broke...we'll help you fix it 'til it is!"

[movin]

When you replace the nut, apply some anti-seize compound to the shaft and nut contact surfaces. It will make removal easier next time.

[This message has been edited by movin (edited 11-03-2001).]

[AirCooledExcellence]

Thanks for all the advice guys. I managed to remove the nut over the weekend!

BUT!

On removing the pulley I discovered that I only have 3 shims on the inside and one outside!!. I've read that there's supposed to be 6 in total?

The cars obviously been running with this setup for long time, but will this cause any damage?

I've put the new belt on and it seems to be tensioned OK (about a quarter inch play in the belt).

Cheers,

Tim.

1983 SC Targa.

[This message has been edited by AirCooledExcellence (edited 11-05-2001).]

[Early_S_Man]

Yes, Tim, the outer pulley half can wobblw and damage the fan and hub if left with only four shims total, because you run out of threads for the nut!

Get some more shims, including 2-3 spares for the glove compartment!
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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[This message has been edited by Early_S_Man (edited 11-05-2001).]

[AirCooledExcellence]

Thanks for the advice Warren.

One thing I did notice though is that even with only 4 shims in place, not all of the nut will fit on the shaft. Is it the right nut?, perhaps it's been replaced with one that's too wide? (it's about half an inch). There's about 1 nut thread visible.

Cheers,

Tim.

[Jim Sims]

Tim, It appears you may have the wrong nut and are missing the domed washer too. Check with Pelican for the correct parts or perhaps Parts Heaven in California. Between the fan and the nut on the alternator shaft there should always be a dished or domed washer (sometimes called a "cover" in the Porsche Lexicon), 6 or 7 shims and an outer pulley half. The shims are added between the fan and the outer pulley half to reduce the effective fan pulley diameter and loosen the belt; this moves the pulley parts further apart and the belt rides further down in the groove. If the belt needs to be tightened, take shims out and put them outside of the pulley under the dished washer. Shims either belong between the outer pulley half and the fan or between the dished washer and the outer pulley half. The dish or concave side of the domed washer goes towards the outer pulley half (towards the alternator) so it can perform its function of spanning over the alternator shaft shoulder where the threads end. As Early_S_man says, if the shims and/or domed washer are missing the nut will hit the shoulder of the alternator shaft and fail to tighten the outer pulley half. I have seen this situation destroy the outer pulley half, the fan and the alternator (by destroying the shaft). Price a fan, outer pulley half and alternator and you'll see how expensive this mistake can be! I have seen the domed washer flattened in a vain attempt to tighten the outer pulley half without the shims. A couple of other notes: (1) if you can't get proper belt tension with between 0 and 6 shims (4 or 5 is more common) between the pulley half and fan you probably have the wrong belt length or an excessively stretched belt and (2) there is a Woodruff key on the alternator shaft (don't lose it) and a thick washer or bushing behind the fan (between it and the alternator) to position the centerline of the fan pulley over the crankshaft pulley. Cheers, Jim

[Jim T]

Look for a groove in the fan shaft, if you have only been running 3 shims, chances are the fan is damages (there will be a groove worn in the shaft).

[AirCooledExcellence]

Thanks for all your advice guys.

I got some more shims, and ended up with 3 on the inside and 3 on the outside before the belt tensioned correctly. Luckily no damage to the shaft or pulley!

Cheers,

Tim.

1983 911SC