The AC in my w123 300TD has been working great since last summer after I serviced and recharged it.

Recently it has been working intermittently, i.e. it will cool for a while and then seems to stop working. Additionally it has been noisy and occasionally lets loose with an awful squeal that sounds like a slipping belt.

I got underneath today and took a look at the R4 compressor and found what I think is a broken part of the clutch assembly, although I don't know the specific names of the part(s) in question.

(see pic below)

There are three arms coming off of the triangle at the top of the clutch. These three arms attach to a thin disk under the triangle. One of the arms has broken the attachment to the disk. I can actually push on the disk and move it out-of-center.

Is this outer layer of the AC clutch replaceable, or do I need to replace the entire clutch and/or compressor?

The clutch drive plate is replaceable and mostly not car specific. There is an early ( bolts around the circumference of the pulley ) and late ( the one pictured ) clutch assembly but I'm not sure if the plate is interchangeable between the two or not.

You will need a clutch plate puller tool and when you reinstall, the compressor shaft nut is used to set the plate clearance. Don't just tighten it until it bottoms out because yo will end up with a locked clutch.

If you have 4 to 6 " clearance ahead of the clutch, you can change this in the car and without draining the system.

If the nylock nut on the compressor shaft is melted out, the slipping generated much heat and the clutch bearing should be regreased / replaced and the shaft seal is going to be suspect.

It's prolly the original and as such has a definite lifespan, I'd not waste a dime on repairing it as brandy new ones are not much $ .

If you like the car and have a few $ to toss at it, get one of Rich's SANDEN compressor and cross flow up grade kits and install it ~ he cool air will amaze and delight you as MORE POWER ON TAP is nice too .

DO NOT use any 'rebuilt' AC compressor, not even if it's free .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Sanden compressor upgrade is in my plans but probably not till next year. I was hoping to keep this one limping along for the time being.

Do all three of the arms pivot on the disk? Or is one of them spot welded on?

The arms are riveted on and flex to allow the round plate to be drawn to the magnet / pulley. The triangle / 3 arms and slotted round disc are all one assembly that you will change.

It is no big deal to change the drive plate. With proper tools and space it takes 15 min.