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Adjusting the shim washers on Corolla 2003 AC compressor clutch

3.1K views 10 replies 4 participants last post by  John Anthony  
#1 ·
AC compressor recently stopped functioning on my 2003 Toyota Corolla. The electrical system is fully operational when I push the AC button in the cabin and turn the fan up, i do get a 12 Volt signal to the AC compressor clutch. I also verified the clutch is receiving proper grounding, ruling out any electrical problem or sensor issue. It seems this car only has a low pressure switch and does not have a high pressure switch. Any idea what the four connections are to the low pressure switch, is it like a dual switch that has a sensor in it as well to read the actual pressure?

Anyhow my main question is as follows: I was told that I can adjust the air gap on the compressor clutch by removing the clutch and removing a spacer washer that will close the air gap a bit allowing the clutch to function once more.has anyone tried this before ? How many miles is it typical to get out of the OEM DENSO air conditioning compressors? I am currently at 250,000 miles on my vehicle and appears to be the original compressor.
 
#4 · (Edited)
After having a look around the factory service manual I found this information:
  • The pressure switch is a dual switch hence the 4 wires: Open with the refrigerant pressure at less than approx. 2.0 kgf/cm2 (28.4 psi, 196.1 kpa) or more than approx. 32.0 kgf/cm2 (455 psi, 3138.1 kpa)
  • the coil resisted to the clutch does not seem to be listed in the factory service manual
  • I will observe the clutch carefully to see if it actually moves some. I do not hear the characteristic clicking noise of the AC compressor engaging at present

* the low pressure line for the AC system has been replaced by the previous owner, as a now have one that says Goodyear on it, so obviously the system has been drained and refilled at least once.

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This video shows replacement of the clutch:
 
#7 ·
at the moment the AC does not work at all, although before it stopped working completely, it would occasionally kick on when driving on the highway. If I put the AC on about 15 minutes into my drive it might suddenly kick on. I suspect this indicates that the field coil itself is still good because if it was bad it would never have the chance to work at all and as such I think the vibrations of driving on the road are shaking the compressor enough for the clutch to suddenly kick in


per this video the resistance of the field coil is 3 to 5 ohms.
 
#9 ·
I tried doing this but nothing happened. I tried lightly poking at it with a crowbar, perhaps I was not applying enough force.

Also, if I look on eBay or Amazon there seem to be plenty of aftermarket air conditioning compressor clutch kits for this car, but I cannot seem to find an OEM grade compressor clutch set anywhere. I was watching a YouTube video where the bearing in the cheap Amazon kit failed and ruined the compressor. I am kind of leaning towards going to the junkyard and finding a low mileage crashed 2008 Corolla and just stripping the clutch set off of it.
 
#10 ·
I removed the clutch plate without actually removing or loosening the AC compressor at all. It also seems that to do the adjustment you do not even need to take off the Serpentine belt although I did do that. The key to getting the compressor clutch plate off is to not pry in the air gap which I did do and cause some damage. The key is to pry at the little gap where the two sections of the clutch plate meat and are riveted together. I also sprayed some WD40 in there. I removed the bolt that holds the clutch plate down using a 10mm socket and a U joint and a very long extension and a little impact gun. When we tightening the bolt I jammed a screwdriver into the aforementioned gap between the two sections of the clutch plate to hold it down while tightening it with a ratchet, using an assistant of course.

After removing the clutch plate I found a single washer under there which I considered standing down power but ultimately just used the washer which is about half its size which I had in my scrap pile.

the AC system is now working again

I also deduced why prying at the air gap is pointless when trying to remove the clutch plate. When prying at the air gap gently, you’re not able to transmit any pressure into the actual shaft to pop the little clutch played off because of the rubber fill in it it has a rubber core separating the two sections of the part just like a crankshaft pulley.
 
#11 ·
I'm glad you got it working. Just trying to understand the sequence you used. The center bolt is removed first before trying to remove the clutch plate, so I hope that's what you did/meant. Spraying any kind of lube in there is not going to help since it won't make it's way to the shaft splines. You don't want to spray or apply lube onto a clutch surface, though. You can use a little bit of anti-seize on the shaft splines if you want. I don't usually find it necessary, though. Another way to remove a stubborn clutch plate is to use whale-jaw vice grips attached to the clutch and then you have something to grab onto both sides to yank it off. Often they slide right off without much fuss.

To answer one of your original questions: I got 185K miles from the original compressor. I used a Denso aftermarket replacement compressor and it has been about 254K additional miles with no issues so far on it. I expect it won't last much longer, but who knows.

Anyway, you got it working, so.......good.