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Old 05-01-2011, 01:16 PM
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sixto sixto is offline
smoke gets in your eyes
 
Join Date: Jun 2000
Location: Eastern TN
Posts: 20,841
To diagnose a shorted clutch coil in my car, I hooked up an ammeter between the Klima and clutch. I saw ~20 amps which is 5 times the spec of about 4 amps. I sacrificed fuses in increasing capacity to confirm. I suppose measuring the resistance would have been easier but I didn't have a spec. You can deduce the resistance spec if you know the current limit is 4 amps.

I replaced the clutch in an 87 300D removing only the radiator. An SDL has more room so it can be done. The snout nut (or bolt in some cases) is easy to remove because it's not on very tight. Forget a strap wrench because the pulley is free to turn relative to the driven plate. There isn't enough driven plate surface for a strap wrench to grip. Borrow or rent an AC clutch holding tool from an auto parts store. The circlip holding the pulley is difficult to reach but it's the circlip holding the coil that will push your sanity across the line. I got a Harbor Freight circlip pliers kit and filed down the pincers for both enough jaw and reach. The circlips have flat and rounded faces so note how they should be installed. Keep track of the shims setting the clutch gap. You might have to play with a collection of shims to get the gap within spec. I got lucky keeping the shims with the pulley and driven plate as a set.

I think there's more room to work if you tilt the compressor down rather than up. That's what did at the yards looking for usable coils. I didn't want to see how far I could bend the 20+ year old AC hoses and fittings in my car.

This is the AC clutch wrench commonly available to borrow or rent at auto parts stores. You have to fiddle with how you use it because all the ND compressors I see on MBs have 4 notches rather than 3 -



Sixto
87 300D
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