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Air conditioner clutch question


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The project tractor 1155 Massey had been converted to 134 by previous owner. We found a leak in the system and repaired, vacuumed down. After refilling and running it is not cooling great and the clutch will squeal but not until I hit pto speed. I was hoping to bale with a cab and ac for the first time in 30 years. Is it possible the clutch could be slipping some resulting in poor cooling before I could hear it squeal or would it be the compressor binding up ? Low pressure side will vary from 15 to 30 and high pressure 200 to 230.  If it matters this system uses a Delco A6 compressor.

Keep in mind when it comes to AC I am dumb as a rock.

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Make sure you have 12 volts to the compressor. I had a system I was working on a couple weeks ago and found the same issue after getting it charged. Started checking voltage at compressor, alternator and finally he batteries. Load tested the batteries and found them to be bad. One had a bad cell and was taking majorly of the alternator power and short changing everything else. 

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30 minutes ago, Dillsburg 560D said:

Load tested the batteries and found them to be bad

Not that it means a thing but it does have new batteries. Will check voltage at clutch and follow through to pto speed and see it it drops off.

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Are those low side pressures a bit low? Put a couple cans in Fils truck and buddy who does some ac work said with the heat  I would probably be around 50 to 55 low side when charged correctly.

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3 hours ago, Dillsburg 560D said:

Make sure you have 12 volts to the compressor.

Excellent suggestion. I know it is kind of an obvious check on any electrical but it is one I didn't do. I found an emergency / rigged wire repair. Replaced that with a male and female connection. No more squeal. I will retest functions later today another project is waiting.

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49 minutes ago, iowaboy1965 said:

Are those low side pressures a bit low? Put a couple cans in Fils truck and buddy who does some ac work said with the heat  I would probably be around 50 to 55 low side when charged correctly.

I honestly don't know but now the clutch isn't letting go we can retest this afternoon. The numbers in my book are for R12 I suppose they are a little different

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9 minutes ago, junkandcattle said:

I honestly don't know but now the clutch isn't letting go we can retest this afternoon. The numbers in my book are for R12 I suppose they are a little different

https://www.forane.com/export/shared/.content/media/downloads/products-documentations/fluorochemicals/forane-134a-pressure-temperature-chart.pdf

Not that I can help you, but this should have the right pressures for 134a 

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I haven't done enough to know what I'm talking about either and any training I did have was in the r12 time period.  I do belive the pressures are a bit different with 134 from what my buddy said.

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4 minutes ago, Ihfan4life said:

Not sure this chart is telling us. Looks like system presure at rest at any certain outside temp? 

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Had to put a whole new clutch on my 2090's York compressor recently. It got really heavy turning and the belt would squeal a bit at times. Turned out to be a dry and heavy turning bearing in the clutch. Works good and back to normal with the new clutch. 

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might check the Clutch spacing on the ac unit i know I saw my neighbor use a feeler gauge to adjust his also could spray it with brake clean to make sure there is no oil on the clutch from a leaking seal or something. 

 

 

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24 minutes ago, searcyfarms said:

might check the Clutch spacing on the ac unit i know I saw my neighbor use a feeler gauge to adjust his also could spray it with brake clean to make sure there is no oil on the clutch from a leaking seal or something. 

 

 

That one I did last night it is  within spec 

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3 hours ago, junkandcattle said:

I honestly don't know but now the clutch isn't letting go we can retest this afternoon. The numbers in my book are for R12 I suppose they are a little different

If the ambient temps are above 90F it may never cycle, the compressor will always be turning. Depending on ambient temps, it does sound like the suction pressure is a little low.

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It sounds like you need more freon but it's hard to tell unless I'm there in person.

Is the high pressure line hot and the suction line cool?

Thx-Ace 

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ok since im dumber than a rock and only have the ability to type and read going for me

since i live in MO also and knowing the temps/humidity around here the past couple days your pressures are definitely low according to this chart. 

my guess would be that its low on refrigerant ? 

as temps increase pressures increase - i do know that and evidenced by the chart

i also know the 86/88 systems use an expansion valve vs an orifice tube 

i also know that if the system has been apart for any significant amount of time, the receiver dryer should always be replaced 

an expansion valve works like this..........it has a lil tube that goes up to the evaporator ( the small radiator looking thing your fan blows thru inside ) and depending on the temp of the evaporator that tube tells the expansion valve to move the diaphragm ( spchk ) inside the expansion valve to make the hole smaller to create more compression of the liquid and make it colder. 

I do not know if its stuck what that would cause, but presumable not very cold air if it doesnt move the valve properly and make it smaller but then again you would need higher pressures i would think.  

I would say get the pressures more inline with the temps on your gauges - then i would see what you have once you do that we might have to troubleshoot further

That isnt much for your cooling situation especially in this heat but thanks for helping me stay inside so i can be cool while reading and typing 

 

image.thumb.png.11c84b80d048179096df682d43576808.png

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9 hours ago, junkandcattle said:

The project tractor 1155 Massey had been converted to 134 by previous owner. We found a leak in the system and repaired, vacuumed down. After refilling and running it is not cooling great and the clutch will squeal but not until I hit pto speed. I was hoping to bale with a cab and ac for the first time in 30 years. Is it possible the clutch could be slipping some resulting in poor cooling before I could hear it squeal or would it be the compressor binding up ? Low pressure side will vary from 15 to 30 and high pressure 200 to 230.  If it matters this system uses a Delco A6 compressor.

Keep in mind when it comes to AC I am dumb as a rock.

It sounds like the compressor clutch is either weak (bad or voltage related) or the compressor has suddenly become hard to turn after the repair. Too much oil can decrease cooling, and too much can slug the compressor (make it try to compress liquid) How much oil did you add to the system. If no oil was added back there is a possibility that the compressor could be hard to turn from lack of lubrication depending on how much oil was lost potentially causing a squealing belt/clutch. I assume it isn't the belt squealing but the actual clutch? 

The low side hitting 15 makes me think the charge is low

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1 hour ago, acem said:

It sounds like you need more freon but it's hard to tell unless I'm there in person.

Is the high pressure line hot and the suction line cool?

Thx-Ace 

 

1 hour ago, searcyfarms said:

ok since im dumber than a rock and only have the ability to type and read going for me

since i live in MO also and knowing the temps/humidity around here the past couple days your pressures are definitely low according to this chart. 

my guess would be that its low on refrigerant ? 

as temps increase pressures increase - i do know that and evidenced by the chart

i also know the 86/88 systems use an expansion valve vs an orifice tube 

i also know that if the system has been apart for any significant amount of time, the receiver dryer should always be replaced 

an expansion valve works like this..........it has a lil tube that goes up to the evaporator ( the small radiator looking thing your fan blows thru inside ) and depending on the temp of the evaporator that tube tells the expansion valve to move the diaphragm ( spchk ) inside the expansion valve to make the hole smaller to create more compression of the liquid and make it colder. 

I do not know if its stuck what that would cause, but presumable not very cold air if it doesnt move the valve properly and make it smaller but then again you would need higher pressures i would think.  

I would say get the pressures more inline with the temps on your gauges - then i would see what you have once you do that we might have to troubleshoot further

That isnt much for your cooling situation especially in this heat but thanks for helping me stay inside so i can be cool while reading and typing 

 

image.thumb.png.11c84b80d048179096df682d43576808.png

Yesterday we had overfilled it fighting with a somewhat defective fill tap/valve and I guess slipping clutch . The problem I was chasing was a clutch that appeared to be holding but would turn loose with a squeal at 2000 rpm. It would seem that we fixed that after finding some horrible wiring splices. The rest of that story is I assumed our 70 / 275 readings were causing to much drag for the clutch so son released some { too much }. No longer in the mood for working AC so I am going to sit in the AC for the rest of today . But thanks to everyone I now have a target for pressure ranges [ tomorrow maybe }    112 degrees under that hood this evening before starting the engine

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1 hour ago, New Englander said:

Can get in trouble real fast with those charts.  Biggest variable is something that has cycling cooling fans, your high side will vary about 100-150 psi when the fan is off or on.  

Lots of variations on different AC systems.....yes, they have all the same components but they can act differently.  

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53 minutes ago, Cdfarabaugh said:

Can get in trouble real fast with those charts.  Biggest variable is something that has cycling cooling fans, your high side will vary about 100-150 psi when the fan is off or on.  

Lots of variations on different AC systems.....yes, they have all the same components but they can act differently.  

Agreed but automotive systems usually have constant running fans so the chart is at least a ballpark. Lots of variables with an expansion valve opposed to an orifice. I wonder if it has a sight glass?  I'm fighting an intermittent now on my pickup. I lost my scan software when the motherboard died so shot gunned a pressure transducer on a hunch - no help. Have a Tech2 clone coming which should help. Of course the system that's run perfectly acts up in the hot weather!

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My 86 series tractors run a little higher than the high side than the chart shows. Inefficiencies in the system tend to change the pressures from ideal. These include dirty condenser or evaporator, etc. Thx-Ace 

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  I never did this with a Massey but I start this way with compressor replacement. The dryer is being replaced anyway or you have no warranty. 

  Never trust how much oil is in the new compressor. Take the plug out of the side in your case, drain and measure the oil while rotating the clutch back and forth.

  Oil amount required changes with application but an A6 system normally takes about 12 ounces. You can put it all in that plug on the side and install the compressor. Now how much oil is in the rest of the system? It needs to all be flushed out. I prefer to flush in the opposite direction of normal flow. Do the lines and condenser Then the evaporator. It is slow going through the expansion valve if you do not replace it.  A little pressure and release. Repeat about 10 or 20 times. There are some A/C flush products, normally expensive, but I normally use denatured alcohol.  It is inexpensive and works well. No smoking and or inhaling. 4 ounces at a shot. Repeat if it did not clear at the end. Use new oil as yours is possibly two different types already. Sounds like your expansion valve is doing OK from your pressures.

  Freon amounts are out the window going from R12 to 134. Make sure your condenser, radiator and in between is clean. Good idea to clean the condenser even if it looks good. Open the cab doors and put it on fresh air. Thermometer in the vent at about 1200 RPM. Probably start with 2 cans. Then add about a half can at a time and let it run for 5 minutes. Keep adding freon until the temperature drops no more.  If your pressures stay inline, safe, you should be OK.

  Is it possible you have pulley grooves for 15, 17, and or 22 series belts and need a different width belt? 

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8 minutes ago, 1066 Peterbilt said:

Make sure your condenser, radiator and in between is clean. Good idea to clean the condenser even if it looks good. Open the cab doors and put it on fresh air.

The first part I did there was some dust, very little matted material, I had done that before sucking down the system. The last part I did the opposite I had it recirculating with the doors shut.

 As for the belt it isn't riding in the bottom of the pulley other than that I didn't look any further 

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