BlackOp

http://www.youtube.com/watch?v=O0mXh31nSxg.

It is spinning very slow and making a loud "ticking" sound. I have fuse #17 pulled just to make sure it isnt being engaged. The A/C switch is not pushed in either..


How can I make the ticking/spinning stop? I dont really care about the A/C...for now.

Thanks,

944Ross

Hard to tell how fast it's turning, but while some drag is to be expected, if it is actually rotating I'd say something is amiss. Is the system charged? If there's no freon in the system, that may be letting a little drag spin the compressor with little resistance.

There are flat metal springs that keep the driven plate away from the rotating hub, if they lose tension or break it will **** the driven plate and it will rub.

BlackOp

This sounds like what has happened. First, is there anything destructive this could cause? Second, do I need to replace the entire compressor clutch to fix it?

The hub (in the video) is spinning pretty fast and the driven plate is kinda spinning slowly...definitely not at the same tempo. The ticks speed up up with RPM.

I had the system professionally charged and it held for about two weeks...looks to be the evaporator. Would replacing the clutch just repeat this if it's not holding a charge?

Thanks...

944Ross

I haven't disassembled the specific clutch the 944's use, but in general you can't buy just the driven plate. I'm sure there are plenty of good used clutches available from people with fried compressors. No real damage will happen as long as the compressor has oil in it, and isn't "really" spinning hard. After a while if it spins hard it could run out of enough oil to keep it lubed and cool. If you want to go to the trouble, on most of these you can remove the driven plate completely, the hub is held to the snout by a snap ring, doesn't depend on the driven plate or the center bolt.

BlackOp

Hmm...when I start the car cold, the tick is still present but the the clutch isnt spinning. Once it's warmed up it starts to slowly spin...could this be due to the metal tabs expanding and catching the clutch? The spin speed isnt consistent in it's rotation..it's more like something is intermittently catching it.

Should I be able tho spin the clutch with my fingers? I can...

944Ross

Yes, you can turn the driven plate by hand, especially if there's no freon. I think I'd remove the driven plate in your situation. Hold the driven plate and remove the center bolt, use a puller to get it off. AutoZone may loan a tool for removal.

BlackOp

I just want to confirm the two can definitely be separated. You had mentioned that you haven't done this on a 944. Can anyone chime in? I'm tempted to just put a feeler out out for a used a/c clutch.

VaSteve

What exactly is your question? I took apart a compressor clutch last weekend. Here's some photos.

944Ross

What I was suggesting is that he just remove the driven plate (first picture), leave the sheave on the nose so his alternator works.

whalebird

If you remove the clutch, you can disassemble it and replace the bearing. That is the most common failure and manifests itself as a dragging drive-plate. IIRC, the bearing may be about $50.

BlackOp

So is the ticking caused by a bad bearing or the plate?

John_AZ

In addition to some great pictures of the clutch disassembly, here is a PDF.

My opinion is that you will need to reseal your old compressor (soon) if the front seal was leaking like most due.

http://www.944time.com/porsche/2007i...5C-rebuild.pdf

GL
John

BlackOp

I read the PDF (thanks) and it mentions putting shims (.4 to .7mm) between the pressure plate and the rotor. I'm curious if this was out of spec if it would induce the ticking and drag/friction....