Need to ID This Part - '77 450SL

[ncgirl05]

Hello!

Taking a Sunday drive last week when I heard a weird sound come out of my 450SL, like a sporadic rattling. I got the car home (which drove fine despite the sound) and my boyfriend told me leave it running while he looked under the hood. He saw some sparks so he told me to turn the car off (Turn it off! Turn it off!).

What we found was a part (shown in the attachment) had come apart somewhat. I have no idea what this part is, but it's on the engine, beside the bottom of the charcoal cannister (which we took out in order to look at the part). The spark was the wiring beside this part - when the metal was flopping around it was hitting the wire. First pic is the bad part, second pic is a farther out shot in order to orientate.

WHAT is this part?? Anyone have any experience with this?

Thanks much!

LA

[230/8]

NCGirl:

Are we looking at the magnetic clutch on you AC compressor? Your description sounds like an AC mag-clutch failing and breaking apart. They will squeel, scrape, and spark as the magnetic coil disintegrates. Sounds awful, but not fatal to the car, just to the compressor and clutch. If that was/is your problem, you may get lucky and only need to replace the magnetic clutch.

230/8

[ncgirl05]

Is this an easy fix? Any advice before we pull the radiator off?

Would taking the belt off for now cause any problems?

LA

[ericdee]

Yeah, you'll be ok, just pull the belt off.

[Roncallo]

That is the AC compressor clutch. There should be no problem pulling the belt off as long as it does not drive anything else, like water pump, power stearing alternator etc. I belive that for the 450SL the belt only drives the compressor.

As far as fixing it. Did you have the AC on at the time of the incident? If so the problem is most likely a siezd compressor and you will have to replace the compressor and clutch assembly. If the AC was off then the problem most likely is limited to the clutch. If its just the clutch you can do this inside the car without removing the compressor and discharging the system, but you will need a special GM AC clutch removal tool.

Lucky you. You have a GM compressor. Not only are they the best compressores in the world but because they were used on 90% of all GM cars for about 20 years they are cheap. In any case if you need to get it recharged insist on a place that can charge it with R-12 Freon.

John Roncallo

[ncgirl05]

Thanks guys! We pulled the belt off yesterday without incident.

John, thanks for the additional info. The day of the "incident" I was playing with the a/c and noticed that it wasn't blowing cold air, so I kept turning it on and turning it off.... the clutch went out (or rather, made lots of noise) when it was turned off.

LA