OK guys...i searched the forum and cannot find info on removing the shim from the compressor for a sticking clutch. Everything on my 99 f350 for the ac works fine, but the clutch will stick and cause hot air to enter. I saw somewhere that you could remove the bolt on the clutch and remove one of the shims. I did that, but saw no shims......all i saw in there was a rubber washer? Are the shims behind that??

 

Removing shims will not help a sticking clutch. Removing shims is a cure for the lazy clutch syndrome. As the clutch gets weak with age or the distance between the clutch plate and the pulley increases due to wear you can remove the clutch plate and between the shaft and the plate there should be some washers of varying thickness that can be removed. Idealy the distance between the plate and the wheel should be between .020-.030 range, but as wear increases I have seen a much as 3/32" distances.
Oops just reread you post sounds like you clutch disengages but wont re-engage?? If that is the problem between the end of the compressor shaft and the clutch plate there should be several washers of varying thicknesses. The washers will more than likely remain in the sleeve on the plate that slides on the compressor shaft. Only remove enough washers to get that .020-.030 gap between the wheel and pulley. If you do not have any washers it sounds like the clutch may need to be replaced. I replaced one on one of my other trucks and the clutch assembly was approx $100.00.

 

So if i have my AC on max, and the compressor is always running is there something wrong? Ive heard that it cycles and shuts off every so often.

 

Actually my clutch runs fine, but every so often it just stops spinning. if i jam the gas down, usually it'll start spinning again. I took the plate off the clutch, but did not see any washers. How hard is it to replace? I do have 175k miles on her....but i figured it should last longer than that. Is there anything else cheap i can do to keep it spinning?

 

John, if you have your AC on max and the fan on high your compressor should not quit running. It does cycle but that should only be at higher rpms while driving down the road.If it cycles on and off while ideling on max and fan on high you are more than likely low on freon.
Wolftan, when you clutch disengages tap it with a piece of wood. (I use the handle of the ole ball pen hammer). If it engages and starts going again more than likely the clutch is weak and should be replaced. The clutch is easily replaced: remove the bolt holding the clutch plate on, under the plate there should be a snap ring holding the pulley/bearing assy on, remove the snap ring, slide the pulley off (that can be tough sometimes) but I have found wiggeling it back and forth while pulling and it will come off, then carefully pry the coil off with a big screwdriver between the coil and the compressor housing. Pry carefully you do not want to damage the compressor housing. Reverse the procedure to put the new one on and shim the plate with the washers that are provided with the clutch to get between .020-.030 clearance between the plate and pulley and your done.
If it does not reengage when you tap with the wood try jumping across the pressure switch. It is on the passenger side of the truck and screwis into the low pressure line near the filter/drier/accumulator. If it engages when you jump across those two wires then you are low on freon and need to top the system off. If you do not have guages it is best to have someone top it off for you because too little freon and you still wont be cooling properly and too much freon and you can blow the front seal out of the compressor and.........................

 

i ask because when i have it on high and max it will blow warm air at idle then cold air the warm air.

 

If you compressor turns off and on at idle you could have a lazy clutch or just be low on freon. Try jumping the two wires on the pressure switch. Just unplug the connector and jump the two wires together if the compressor quits cycling at idle then you are low on freon, if not then try the wood bump trick and see if that does the trick. DO NOT leave the two wires jumped together on the pressure switch and just "drive it" or you will be replacing the ac system.

 

It is natural for the AC to cycle, however at low or no speed two things are happening. One is that no cooling air is flowing over the condensor core. Two is there isn't enough compression in the coolant (AC) to help much with the evaporation. Even though my AC will put frost on your punkin' even at very low speed with the heater core shut off valve closed and on max (Max actcually only changes the dampers. Max allows it to recycle the cabin air rather than cooling outsde fresh air.) it is naturall for it to warm up very slightly at idle.

 

Mine starts to blow warm air noticebly, it will blow warm air for about 5 minutes then turn cold again.