Could someone inform me how to replace an AC Compressor Clutch on a 1984 300D Turbo?

This morning, the local Mercedes Shop inspected my entire air conditioning system and said that the compressor clutch was not operating. They informed me they could not order or replace this one particular item, but could order the entire compressor, receiver/drier, expansion valve and recharge the system. This would be very costly.

I have read through the threads on the message board and noticed that some people have replaced the clutch, but I could not find any specific information about the process, tools, or how they did it.

My guess is you have an R4 compressor on it. I think you can fashion a spanner to provide a counterhold to the very front of it (the triangular shaped plate) and remove the nut. But, I'm sort of guessing, do a search, you'll find more. Also, make sure the compressor itself turns freely, as if the clutch failed because the compressor siezed, you'll be wasting your time.

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

Is the clutch not working or not getting power? It's easy to check the clutch operation yourself. Just hook a 12V source (battery) to the 2 pins in the plug socket. You should hear a the clang of the electromagnetic pulling in the clutch plate. If you hear that noise then you know your problem is in the climate control not sending a signal, not the clutch.

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Bill Reimels
Now down to one:
1972 300SE 3.5 W109 (Euro delivery)

If the compressor siezed then the whole system is fouled. You would then need to replace the compressor, condenser and the filter/dryer. Then the remaining components, core, tev, etc.. would need to be flushed. Actually the tev is a $20 part so just replace it anyway.
You without a doubt want to make sure the compressor is still working.

Like Pete said you can "make" a spanner wrench to hold the pulley in place while you remove the clutch nut. I would spray the crap out of it with penetrating oil like PB Blaster over the course of a day or two. Some light blows with a hammer wouldn't hurt if there's enough room.

My experience with clutches is they are a PITA to remove. especially ones that have been on for 20+ years. Not that it would happen to you but I more often than not have broken or bent the compressor shaft. I would STRONGLY encourage patience when working on this.

Replacing the compressor would be best but the R-12 throws a monkey wrench in that.

Good luck.

Danny

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1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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I've had good results with a R12 replacement. http://www.es-refrigerants.com/ . I have both my 250SE and W123 running on it with no problems. I used the lastest esther based oil which eliminates the corrosion issues with R134.

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Bill Reimels
Now down to one:
1972 300SE 3.5 W109 (Euro delivery)

Your link only takes us to the home page. Which "replacement" did you use?

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Sam

84 300SD 350K+ miles ( Blue Belle )

Does the "Air Gap", the distance between the A/C compressor clutch plate and the compressor clutch rotor normally increase with age and usage? My vehicle has 177,000 miles on it.

According to the shop manual, this gap should be from 0.5mm and 1.0mm, on my 1984 300D the gap is closer to 1.5mm. The manual says if this gap is too large, the electromagnetic coil may not be able pull the clutch plate and engage the compressor. Therefore, I am thinking that I need to adjust this air gap back to the correct tolerance and do some testing.

The resistance of the electromagnetic coil is 3.5 ohms, which is the same resistance of another coil in my other vehicle with the same compressor (GM R-4).

If anyone has any experience about this please let me know. I am new at working on this type of problem.

Could you elaborate? About the R-12 and the monkey wrench.

Are you sure the system is charged? If it isn't the clutch won't work, it still will if you hook the 12v to it like billrei said, but not on it's own.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

Thanks for all the posts concerning my inoperative AC compressor clutch on my 1984, 300D Turbo.

I did take my car this morning to the Mercedes Shop and they ascertained that: there was sufficient charge at the low pressure switch, that there was both power and ground at the A/C clutch. They informed that the A/C clutch was not engaging.

I examined the compressor and found it was manufactured by General Motors (GM) and model number 111350. It also said Harrison on the label.

Most people don't have the necessary equipment to work on R-12 systems. Unless of course you don't give a crap about the environment and just vent to the atmosphere.
It's not like you can walk down to the local Auto Zone and buy gauges, refrigerant, etc..

Monkey wrench=not impossible just a little more difficult.

Danny

__________________
1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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