A-C clutch

stonerock · Jul 28, 2019

4430 through out the years a lot of trouble with the air, tractor has five thousand hrs, old compressor quit working clutch was paulsating a lot instead of coming on and running a while ahd shuting off, new compressor is doing the same thing but is doing a good job cooling. what is causing this? should I try to fix it or let it go?

Janicholson · Jul 28, 2019

Two ideas from looking out my window at a catalpa tree. Over charged, and or restricted expansion valve. Pressure evaluation of high and low sides, as well as a hand held infrared temp sensor will help. Jim

stonerock · Jul 28, 2019

Janicholson, hand held temp sensor what am I trying to read? where

Janicholson · Jul 28, 2019

Restrictions in hoses, a receiver dryer, or a bent pipe, will show up as a differential temperature change where the restriction is located. there are also temperature based specifications for high and low sides based on rpm/ambient temperature. If the cycling is intermittent (irregular) a connection to the clutch, or a failing relay could be at fault. A steady pulsing stop start is more likely a refrigerant/pressure issue. Hoses fain internally and hold pressure but restrict flow. Jim

r.w.b. · Jul 28, 2019

Spray water on condenser,if it acts normal while spraying water on it you have a restriction in lines.
Have you checked voltage at clutch also?

Bob · Jul 28, 2019

Fix it or you will "kill" the clutch.

Unless it's been updated/modified there's NO hi or lo side pressure switches, only an "overheat" sensor clipped to the condenser, and they don't cycle very fast from tripping at overheat to resetting once the condenser cools.

Do you know if it's been modified with added pressure switch(es)? Also, from the factory, there's no relay in the system, although someone could have added one.

If NOT, I would suspect a bad electrical connection somewhere, could even be at the breaker at the left of the steering pedestal.

da.bees · Jul 28, 2019

Like so many things,ACs dont't tolerate tinkering and can quickly become worse when improper procedures are used. First thing you should know and understand is how system regulate's to prevent freezing up. "Back in the day",many systems did not have suction throttle valve or other means of modulating system pressure. Instead,the clutch dis-engaged when temperature was reached then re-engaged when cooling is needed. Ford Motor Company used this extensively. ARA which built the majority of off-road systems used it as well. Your ac might be working as it should so check this out before digging in.

A-C clutch

stonerock

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Janicholson

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stonerock

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Janicholson

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r.w.b.

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Bob

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da.bees

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