First time fan belt replacement

avale · 04-03-2011, 06:05 PM

Looking for a bit of info (as I think I'm over thinking this thing). I'm about to change my fan belt for the first time and I completely understand how to do that (shims, etc. - I have Wayne's Porsche 101 Projects book). What it doesn't cover is loosening up the AC compressor so you can remove that belt first. What do I need to do to loosen up the compressor to remove the belt? More importantly what do I need to do to reinstall the AC compressor belt and have it be in the correct position so that the pulleys are aligned? I did a search but didn't see anything immediately that addressed this. My 911 is an '87. Thanks in advance!

jcsjcs · jcsjcs's Garage

I had the toughest time loosening my AC compressor the first time! Tried a couple of times - and finally got the leverage required to do the job.

Then I had trouble getting the fan belt to fit. I would have sworn that it was too short - until I finally realized that as I tightened the nut everything worked itself into place. Take your time - use Wayne's chapter as a guide (though I don't think that chapter gave enough detail for a first time fan belt replacement ) - and post here if you get stuck.

Canada Kev · 06:15 PM

Use a half inch (or metric equivalent) socket to loosen the three bolts plus one nut holding the compressor to the base. Push the compressor to the left (driver's side) a little bit to relieve tension on the belt and then slide the belt off. Installation is the reverse of removal.

When I first did mine, I almost missed the nut hidden behind the compressor. You won't be able to fit a socket into that spot, IIRC. Once the fasteners are loosened, it should slide easily. If not, you may have to remove a couple bolts.

The fan belt can sometimes be a PITA. If you think it's too loose, turn the engine over a couple times and the belt will work it's way to the outside of the pulley. You might find, then, that could be too tight. Or too loose, so that you have to add or remove shims. After the engine turns over a few times and the belt takes it's final position, remember to retorque the nut again. Good luck.

DRACO A5OG · DRACO A5OG's Garage

Mark the position of the bolts and especially the tension adjustment nut, loosen/remove it and then loosen the remaining mounting bolts and slide it in. you may need to use a screw driver to pull the belt off.

Now tackle the fan belt.

A trick I found to re-install the A/C belt is to place it on the edge of the compressor and crank the car once to pop the belt back on. If you car tends to start right away, then make sure you turn off immediately, for obvious reasons then slide the compressor back then adjust the tensioner to the same spot, if you are anal, then tighten to spec, 1/2" play in the slack.

Jim

rusnak · 04-03-2011, 06:52 PM

whatever you do, check the belt by turning the fan pulley by hand before starting it up with the starter.

I install the fan nut finger tight, then push the washers into alingment under the cup washer. If the washers won't budge, then loosen the fan nut slightly, then try again. Once the washers are aligned, tightnen the nut fully.

Canada Kev · 04-03-2011, 07:42 PM

Whoops, sorry. Forgot about the compressor tensioner screw/nut. Jim caught it, though.

avale · 04-03-2011, 08:51 PM

This is great. Thanks for all the information!

AlfonsoR · 04-04-2011, 06:34 AM

Don't know if you're done, but maybe for other folks...my 2 cents

1. buy the Conti belt, not the Porsche (by goodyear of Mexico). The Porsche belt is a bit smaller in diameter and a few folks have trouble getting on, i know i could not get it to fit right, too much tension even with all the shims installed. And not a big deal really, but the Porsche belt is made in Mexico, not Germany so what's the point of buying OEM.

2. Make sure you observe the orientation of the cup washer. I installed mine backwards and screwed up my alt shaft when i did a test run. Any way, the flat part of the washer should be facing you (to the rear) as you install it, which means the cup points forward.

Wil Ferch · 04-04-2011, 04:35 PM

Didn't fully read all the responses but IIRC, on my 85....the AC compressoer was held "down" by 4 nuts, 12-13 mm or 1/2"......and there was a 5th tensioner screw to the far right....horizontal,...kinda in front of the oil filter under your nose, that ( now that 4 hold-down screws were loose)....that now can be loosened to allow you easily slip off the AC belt.

vracer · vracer's Garage

FWIW, I had to have my alternator changed due to intermittent overcharging. The shop replaced the fan belt as is good practice and used the $4-5 version. It turned out to be a bit long, and only needed one spacer on the pulley. That started to stretch after about 500 miles, so I took out the only spacer leaving no further adjustments. It was "on the loose side" fairly quickly.
I'm getting ready for the Targa California and don't want to deafen other drivers with the squeals. I replaced that belt with a real live Porsche Hecho en Mexico belt. It is so tight that all six spacers had to be used.

Wil Ferch · 04-05-2011, 07:55 AM

All six spacers should ALWAYS be used !!!...... the only variation being how many go BETWEEN the pulley halves...and how many UNDER THE NUT ( but outside the pulley halves). If you use less than 6....you risk damaging the alternator shaft/threads.

vracer · vracer's Garage

Quote:

Originally Posted by vracer

FWIW, I had to have my alternator changed due to intermittent overcharging. The shop replaced the fan belt as is good practice and used the $4-5 version. It turned out to be a bit long, and only needed one spacer on the pulley. That started to stretch after about 500 miles, so I took out the only spacer leaving no further adjustments. It was "on the loose side" fairly quickly.
I'm getting ready for the Targa California and don't want to deafen other drivers with the squeals. I replaced that belt with a real live Porsche Hecho en Mexico belt. It is so tight that all six spacers had to be used.

Will, thank you; I was unclear. I meant that all had to be used inside the V pulley to make room for the shorter belt. I guess I shouldn't assume everyone has the depth of knowledge you & I have. ;>)

AlfonsoR · 04-05-2011, 11:40 AM

Quote:

Originally Posted by Wil Ferch

All six spacers should ALWAYS be used !!!...... the only variation being how many go BETWEEN the pulley halves...and how many UNDER THE NUT ( but outside the pulley halves). If you use less than 6....you risk damaging the alternator shaft/threads.

I think that's what he meant, all six spacers in between the two pulley halves. This was my experience too, and it still felt too tight, so I went with a Conti instead. If it's too tight you end up eating the bearings on the alternator.

Wil Ferch · 04-06-2011, 04:49 PM

Didn't want to come off as a wise guy.....but some new folks might not have "gotten the memo"....that you always use 6 total in some combo under/over the outer pulley half. Thanks for clarifying.

avale · 04-13-2011, 04:51 PM

Thanks for all the great advice- it was all spot on! I finished the job today and I figured I would do a little "how-to" with a few pictures to help others. As Jim mentioned above, I marked all three of the bolts that hold down the A/C compressor with a pencil.

I then measured where the tension adjustment bolt was in relation to the casting.

Marking the position of the bolts worked so well that I don't think it is necessary to measure the tension adjustment bolt but it is always good to have this as a check. Next I loosened up the 3 hold down bolts with a 13 mm wrench so that the bolts stuck up about a 1/2" above the casting. I then loosened up the retention nut on the tensioner and loosened the tensioner. I then slide the A/C compress all the way towards the fan. The reason I loosened up the hold down bolts so they stuck up an extra 1/2" is because this allowed me to rotate the A/C compressor towards me a small amount. The combination of sliding the compressor all the way to towards the fan plus being able to rotate the compressor slightly towards me allowed me to remove (and later install the A/C compressor belt) without a huge amount of trouble. To reinstall I put the belt back on, tightened the hold down bolts so that I could still rotate the washers by hand, tightened the tensioner so that my bolts/washers lined up with my pencil marks and then tightened down the hold down bolts. I then rotated the pulley a couple of times and then tested the belt tension (should be able to flex it 1/4 - 1/2" in the center of the belt). I then tightened retention nut and tightened down the hold down bolts the rest of the way.

The trickiest part of installing the new fan/alternator belts was making sure that any washers on the outside are lined up enough that they position themselves correctly when you tighten the nut.