tab a

I've had this '85 for a couple years and the a/c has worked fine. IIRC, early last summer I thought the a/c belt was squealing on start up, and I found it to be a little loose, so I tightened it. I'm not sure now, but don't think I was able to get it quite as taut as I'd have liked. More squealing (just on start up) later in the year and now I find that it is quite loose and I can't come anywhere near getting it tight. I've replaced plenty of worn-out belts but don't think I've ever seen one stretched. Is that likely or should I be looking for another explanation? I know the PO replaced the compressor on this car but don't know if it's the correct one.

Thanks.
Thon

Mrmerlin

first make sure all the mounting bolts are tight on the compressor 2 top pivot bolts and one lower tensioning bolt ,
then make sure the mount at the girdle has not broken.
Find out what size the belt you have is and compare it to the correct size listed for your car.

Based on how loose this belt is ,
something is broken or a bolt has fallen out of the compressor mount,
Or the AC pulley has gotten loose.
OR as you suggested the belt may be internally separating

WestInc

You say the belt hasn't been changed in a "couple of years", it may well be the time to replace it. If we suppose that this belt IS the right one, then strech and wear is enough for this to happen. It sure looks to be worn and "squeezed". Considering where it rests on the pulley being that loose, it sure looks to thin now. Maybe mounted too streched from the beginning?

tab a

Pretty sure the belt is correct size-- 13 x 1125.
Also fairly certain 2 top bolts are tight. With tensioning bolt loose, I can't budge compressor by hand.
How do I check mount at girdle? Do I need to remove compressor to do that?

Thanks.

Mrmerlin

just loosen the bolt at girdle on the airpump side.

NOTE after looking at your picture it looks like you need a new belt, see how the teeth on the belt seem to get thin.

NOTE I would suggest to Call Roger and order a new set of belts ,
recheck the tension after 500 miles

Speedtoys

That just looks like the wrong belt..

Didnt some cars for auto/5spd have different length AC belts?

I ran into this on my 87...initially got the wrong belt. Was too long.

tab a

Wow, if that's not an optical illusion, it looks like the belt teeth are totally gone! Seems impossible but will double check that tomorrow.

My reading here seems to indicate there are 2 different length belts, and this is the longer--which goes on compressors with a larger pulley, which I think this is?

Thanks again.

freakngeek

13x1125mm on my '82 AC
You're going to have fun getting new belt on getting past in your case 3 others ?

The Compressor doen't look original, as it has single ear for bolting adjusting bracket to, yours look to have 2 ?
At the top of the compressor are there also 2 ears ?
I'm possibly leaning top left ear is used vs using right one will push the compressor further away making belt tighter

Mrmerlin

FG the OP would remove all of the belts and replace all of them with new belts.

NOTE the AC belt appears damaged it might have gotten smoked by a freezing up compressor.
The lower lug that the compressor is attached with is the correct one .
NOTE the compressor may not come close enough to the crank to install the new belt .

tab a

Here's what the belt looked like. 3 places where the teeth are worn off!
Pulley spins easily, though I do hear a faint sound when spun--not a rumble or grating or metallic noise.
Am I supposed to think the pulley froze up sporadically?

Mrmerlin

yes the AC compressor is probably getting ready to seize.

NOTE if there ever was a refrigerant change the chance is good that the oil was mixed,
and you now have funky oil .

R12 runs on mineral oil, the 134 could use Pag or Ester.
look in the window of the drier to see what color this might be it should be clear with a few bubbles.

NOTE you could also have a damaged pulley, where the pulley run is not smooth,
meaning the wall of the pulley is closer to its other side this could make the belt wear funny.

Make sure to replace your full set of belts., based on the condition of this belt they all need to be replaced.

Do more investigation to determine the root cause of this issue

Michael Benno

In addition to what Stann mentions. The failure of the intermittent failure compressor could be a result of something larger mixing refrigerant oils, not enough oil, and or debris in the system.

Either way, it means the AC system should be given a good cleaning/flush before installing a new compressor. This would also mean replacing the O-rings, receiver drier, and expansion valves.If you are unfamiliar with AC work, The work is time-intensive but not complicated.so bringing it to a pro is expensive. I'd recommend you tackle it yourself. we all here can help provide guidance.

Here is some helpful information on the compressor which is manufactured by Denso:

• Porsche PNs: 928-126-010-06 (original), 928-126-010-71 (replaces 928-126-010-06) 928-126-010-FX (rebuilt)
• Denso PN: 471-0122

There are rebuild kits to replace the seals and the bearings, but that would not remedy any damage to the internal pistons.

76FJ55

The pulley is mounted on a bearing that will spin continuously, even when the compressor isn't engaged. To see if the compressor is locked up you would need to turn the compressor clutch located in front of the pulley. when the A/C is energized the clutch binds the compressor shaft to the spinning pulley to drive the compressor. when it is not energized the pulley still contiues to rotate but the clutch and shaft of the compressor stop rotating and remain stationary.

tab a

[QUOTE=Mrmerlin; NOTE the compressor may not come close enough to the crank to install the new belt .[/QUOTE]

You say this because??

Finally got back under the car, and did NOT have a pleasant day. Alternator belt came off easily, as I'd just had the alt. off recently. Air pump belt was a SOB. I've read here that some of you 'loosen' the fan mount bracket bolts and that 's enough but it didn't work for me. Eventually pulled off the throttle cable bracket attached to the fan mount bracket, and THEN the fan bracket and finally the belt. PSP belt was not too bad though without seeing a pic here I wouldn't have known about the 4th bolt hiding down low! Thank you!

I'd cut off the old ac belt and COULD NOT get the new belt anywhere close to on--as MM noted above--even with the compressor easily pivoting. The body ran into the cradle too soon. Presumably this SHOULD work so that gets me back to is this the wrong compressor? It seems to me, as fng said earlier, my compressor should only have one lug at bottom, not 2? (I very crudely measured the OD of the compressor pulley at about 5.75 inches, if anyone's got a pulley handy to measure.) In any case, the correct belt WAS on it, so I'm guessing the PO dropped the compressor a few inches, put on the belt then put it back up? How much of a PITA is that? Just the front and back pivot bolts at the top, or is it easier/possible to drop the cradle?
Thanks again.
TB

76FJ55

I am guessing you still have the original compressor. The factory installed compressor has 2 lower mounting lug, just as yours does. I know this to be the case as on my original compressor on my 85 the PO had actually knocked of the tensioner ear (too low ride height, sagging engine mounts) that the bracket is attached to and then cobbled together an extension to the tensioner arm to tension off the second ear. the used replacement compressor I got from a fellow RLer also had 2 ears as does the compressor on my 86.5.

the dual ear configuration continued through the S4 as well as can be seen in the pic below.