B4V Air Conditioning Clutch Replacement?

[GeWilli]

Anyone changed just the clutch on these? My compressor works fine but the clutch plates are wicked loose. With the AC on it does get a bit quieter but with it off? It is loud.

It had been making a little rattle for a bit but lately it has become worse quite suddenly.

I tried to tighten the nut down last weekend and it was solidly not moving at all but I just noticed the plates were flopping around...

 

[TonyJetta]

Sounds like the bearing is about to fail.

Do you have the original compressor? If so, see if you can find someone parting out a car in the for sale section and buy a used compressor and remove the parts you need.

A little over a year ago, I was in a situation, where the clutch coil wire was cut by the pulley, due to faulty installation. I tried like crazy to find a new coil, but could not. I had to buy a new compressor.

HTH

Tony

 

[IndigoBlueWagon]

Clutches are more expensive than complete compressors with clutches. Go figure. Used may be a good way to go. I think you can use a compressor from an A4 if you swap the connector over, but I'm not certain.

 

[schultp]

Clutches are not as expensive as a whole new compressor. I just did this repair.

I bought the parts from an excellent ebay vendor. He even helped me with getting the proper parts. He called me at home to walk me through the diagnosis and repair. Great service.

The bearing is likely going on your clutch pulley. It is possible to remove and replace the bearing (search youtube for videos showing the process). Removing the pulley while the compressor is on the engine is a PITA. I have done this twice and the frustration level is very high. This is due to the fact that you have about a 3 inch gap to work in between the inner fender and the pulley.

I should have taken pics while I did this procedure. if you are interested I can walk you through it. I have accumulated the proper tools to get this done. Send me a PM if interested.

The upside of doing the repair without removing the compressor is that you leave the AC system closed. (No need to evacuate refrigerant, replace receiver/drier, flush system, vacuum system to remove moisture, and then add new refrigerant.)

Instead of going through replacing the bearing. I would recommend you buy a new pulley with bearing already installed. Also, you may end up buying a new clutch hub since if you are not careful in removal it gets slightly bent.

 

[GeWilli]

Hey Paul. Good stuff!

I did get the nut off, but didn't spend a whole lot of time prying at the clutch (just put the nut back on guttentight).

It was quiet for a minute then got loud an cranky again.

Part of me really wants to just do the AC delete at this point, but not sure how practical that is.

Swapping in a different clutch (even if i get a used AC unit from a bone yard) is highest on the list of approaches at this point.

The PO had the AC system replaced a year or so before I acquired the car, and it was working fine (until this noise started):
http://www.vimeo.com/24244011

That's a quick clip of it. There is visible wear on the round 'rivets' on the ends (near the pulley) and some decent metal dust. The inside of it is pretty dirty, but then so is the rest of the car since it had a couple months of driving with a broken CV return hose.

I've just run into quotes like this tonight:
"But my Nissan tech friend with 40 years on the job says "don't". Historically changing the clutch alone has often resulted in the punter returning a few days, weeks or months later with a dead compressor. "

That said this isn't a daily driver now. Generally a weekend car for getting me and my bikes to the races. Most of my racing is in the fall and winter, so AC is very low on the priorities.

Typical GeWilli fashion running around all the options numerous times looking for any/all angles to approach the problem.

 

[schultp]

GeWilli,

I got your PM and sent a reply. I also took a look at your video. I assume this video is with the AC off. The clutch appears to not have been shimmed properly since it is catching occasionally. I have to admit I couldn't make out the noise in the video over the engine noise.

As for your decision on how to proceed it depends on how old the compressor is. If it is only 1-2 years old then it may be worthwhile to try and replace the clutch and pulley bearing. I do agree that if this is the original compressor it is more of a risk replacing the clutch since the compressor itself could be at the end of its usefulness.

Using two screwdrivers to pry the clutch hub off is possible if you have the compressor on a work bench. Otherwise, you cannot get proper leverage with the compressor still in the car and you end up bending the clutch hub...I know from experience. Fortunately, I have a clutch hub puller and modified it to be able to use in the narrow gap between the passenger inner fender and the face of the AC compressor clutch.

Once the clutch hub is off there is a snap ring that holds the pulley in place. Removal requires a specific size snap ring pliers since the snap ring is in a recessed portion of the pulley. I bought this tool on ebay so I could complete this project. Even with a set of pliers that can access the snap ring it is still a blind procedure and getting the tips of the snap ring pliers into the small holes in the snap ring takes time and leads to increased frustration.

With the pulley off the bearing can be replaced. Then, installation is in reverse order with all the same frustrations getting the snap ring back on.

When you reinstall the clutch hub it needs to be shimmed properly so that it doesn't catch when the AC is not engaged. This requires putting shims in place, installing the clutch hub, testing, removing the clutch hub and adding/subtracting shims. Shimming could take a couple removal/install cycles with the clutch hub.

The ebay vendor that I worked with was "allforauto". His name is Adam.

Remember, your compressor may have a keyed shaft. The clutch hubs he has on ebay are for a splined shaft. I recommend not ordering until you have your clutch hub off and can confirm the type you have. I ordered and ended up having to exchange for the keyed shaft type. He had to get this from his supplier since the splined shaft type is more common and the only one he routinely stocks. He also supplies about 4 shims with the clutch hub.

The AC bypass pulleys are easy to install (I had one of these on my pickup truck for a couple summers). But, even when you use the vehicle rarely it is nice to have AC on those hot summer days. I reinstalled AC in my truck for this reason.

Whatever you decide you'll find plenty of help on this forum. Good luck!

 

[GeWilli]

well, Paul, good suggestion.

So I took the nut off yesterday, but what did I not do? I didn't bother to try and spin the pulley by hand with the belt off.

Just tried that. It no spin.

Needs a bit more than just an AC clutch.

 

[schultp]

well, Paul, good suggestion.

So I took the nut off yesterday, but what did I not do? I didn't bother to try and spin the pulley by hand with the belt off.

Just tried that. It no spin.

Needs a bit more than just an AC clutch.

The pulley doesn't spin freely by itself? If so, this is likely a worn pulley bearing and could be repaired.

Or, if the pulley is sticking to the clutch hub and the entire assembly doesn't want to spin as a unit? If so, then the compressor shaft is not moving and the compressor likely has an internal failure and needs to be replaced.

 

[GeWilli]

the second one...

 

[schultp]

the second one...

That's unfortunate. Your choices are either a used compressor or an AC bypass pulley.

You may find a used compressor that costs about the same as the bypass pulley. You could install the compressor and immediately reattach all the lines so the system is closed and doesn't remain exposed to the elements. You just don't want to plug in the clutch electrical connector. Then, the compressor acts as a bypass pulley for about the same price.

The advantage is that later if you want to attempt to get the AC functional again you already have the compressor in place.

However, if you take this route then do not run the compressor even once since the receiver/drier, evaporator, condenser, and lines may have metal shavings in them from your defective compressor. If these flow through a running compressor it would potentially lead to its failure. Just leave it unplugged so no one can possibly accidentally activate the compressor.

A future rehab of these parts would require a thorough flushing of the components (and preferably replacement of the condenser, receiver/drier, and accumulator).

If you go with either the bypass pulley or a used compressor you will need to open the AC system. Either choice requires you to go to a shop and have them evacuate the residual refrigerant from the system.

R-134a is harmful to the ozone layer, just not as bad as the old R-12. In a couple years R-134a will be retired and replaced by an extremely ozone friendly alternative (something like R-1234 IIRC).

Good luck.

 

[familytractor]

you sure its not the air gap that need to be adjusted? the jist is if the a/c is off and the noise is rattling or scraping, it sounds like the air gap between the armature and clutch that needs to be reset. the noise will go away if the a/c is on, assuming the gap isnt too large and the a/c will then not engage the compressor. it comes on quite quickly, and the fix is five minutes with the right puller or shim pack and puller, compressor depending...the center hub bolt may be independant of the armature and have no effect on it as it may not bottom on the armature...

cheer darren

 

[GeWilli]

could be but a shim would help, or I should say, would HAVE helped when the noise would go away when you put the AC on.

now? noise doesn't go away. my fault for not addressing it early, but there were higher priority issues (like getting it ready for inspection).

It may not have been shimmed correctly when the system was fixed by the previous owner's mechanic, or it just is a clutch gone bad taking out the rest of the compressor assembly.

 

[GeWilli]

could be but a shim would help, or I should say, would HAVE helped when the noise would go away when you put the AC on.

now? noise doesn't go away. my fault for not addressing it early, but there were higher priority issues (like getting it ready for inspection).

It may not have been shimmed correctly when the system was fixed by the previous owner's mechanic, or it just is a clutch gone bad taking out the rest of the compressor assembly.

 

[GeWilli]

update:

So the clutch really wasn't so much the issue as the bearings in the pulley. There were some ball bearings left in there but they were stacked up (and it wasn't spinning).

No wonder it was making a hell of a racket.

Picked up a junkyard compressor for cheap with a good pulley. The junker may or may not work (the compressor side) but there was a tiny bit of corrosion inside it so i'm not chancing it and plugging in the electrical connection.

There was still some charge in the old system and based on it working until the clutch self destructed the core is still in working order. Just no pulley. Okay the pulley is there but the bearings are gone and the clutch isn't so good.

If someone has a dead compressor and a good AC/pulley they want to swap on and try out you're welcome to my old parts, that or i get $20 back for the core. So no, I don't have A/C anymore but then I never used it anyway.

But the car purrrrs right now.

And is finally back on the road. Time for new ribbed belt (the one that is on there is pretty heat stressed from trying to turn that pulley w/o the bearings).

 

[paulgato]

Just a question...

Ehhm, ...just a question... Instead of using a dead compressor as a dummy pulley, or getting a dummy pulley, can you remove the A/C compressor entirely and just get a shorter belt? Not sure if the Mk3 is the same as my Mk4 Golf Tdi, but that's what I did. I got a serpentine belt for the version of the car that had no air conditioning, and it worked perfectly. It now drives the alternator and the power steering pump with lots of lovely space in between where the A/C compressor used to be. Much easier to get hands in there to change or re-fit a belt or whatever.