Help Needed A/C Quit

[wcsmithiii0911]

Me and the wife were headed for Emeril's Fish House Monday (7/21/08) and the A/C just quit. The Ms gulf coast is no place to be w/o A/C. The truck is an '04 F250 SD and has been going strong since replacing all the injectors. The low side pressure is reading 100+ and appears to hold when the engine is shut off. The pressure switch has 12v when the switch is on, of course ground on the other pin. It appears to me that the compresser is not turning; I can see the belt pulling the pully wheel around but the center is not turning. It has been so long since I worked on A/C, if my memory serves me correctly the center piece [triangular spring loaded piece] will be rotating when engaged and not rotating when the switch is off. Correct me if I am wrong.. Any assistance will be greatly appreciated. Bill

 

[JRJ04]

Sounds to me like your compressor might have frozen up. But, if thats the case it might have thrown the belt so I'm not totally sure. Someone will help you out. Good luck!

 

[Tbar]

....... if my memory serves me correctly the center piece [triangular spring loaded piece] will be rotating when engaged and not rotating when the switch is off. Correct me if I am wrong.. Any assistance will be greatly appreciated. Bill

That is correct.

I am not sure what the compressor reading should be but try this simple test before going any further.

Start the truck and turn on the a/c compressor. If the center piece is not turning carfully tap it with a screw driver. If it starts working it might be excess clearance on the clutch due to wear. If this is the case you can remove a shim to buy some time before you have to replace the compressor.

Others will be along in a minute with other suggestions.


Tbar

 

[wcsmithiii0911]

Thank you. Getting old doesn't seem to have taken any reasoning away from me. Can I do this without taking the compressor out of the truck? Is there any way to check the field coil and clutch before disassembly? I have unplugged the pressure cycling switch on the accumulator then jumpered the plug and still no change. Can you think of any further checks I need to do prior to disassembly?
Thanks again,
Bill

 

[powerboatr]

100 lbs on the low side seems awfully high my book says low should be 45-55 psi at 90 F high side 250-270 psi
and 50-55 psi at 95F high 275-300 psi
50-55 psi at 100F high 315-325 psi


what was your high side
high low and high high inidcates an over charged system


bite the $$$ and go have it fixed if you dont have a recovery and purge unit available for use


the fish house WOW $$$ enjoy

 

[JLDickmon]

100 lbs on the low side seems awfully high my book says low should be 45-55 psi at 90 F high side 250-270 psi
and 50-55 psi at 95F high 275-300 psi
50-55 psi at 100F high 315-325 psi


what was your high side
high low and high high inidcates an over charged system


bite the $$$ and go have it fixed if you dont have a recovery and purge unit available for use


the fish house WOW $$$ enjoy

if it's not operational, both sides will be near ambient.
so the 100 psi or so is not a biggie..

if you have a bed of nails and a test light (or better yet, a logic probe), you can come a safe distance away from the compressor and check; should have power through the compressor clutch... use the bed of nails to pierce both wires and check for power on both sides with the compressor plugged in, AC on. When you are done, slop some of that 3M brush-on electrical coating on the wires where you pierced them.

if you do, you can try Tbar's trick..

if you do not, the clutch coil has gone open

if you have ground on both sides, you most likely have a bad cycling switch..

speaking of that.. you did check the fuses, right?

 

[JLDickmon]

The pressure switch has 12v when the switch is on, of course ground on the other pin. Bill

I just went back and re-read that..
if you tested the switch with it unhooked, you've got good fuses..
if you checked it with it plugged in, and backprobed it, you've got an open cycling switch.

 

[powerboatr]

I just went back and re-read that..
if you tested the switch with it unhooked, you've got good fuses..
if you checked it with it plugged in, and backprobed it, you've got an open cycling switch.

yeah me to
duh i didnt quite catch the fact or not if the compressor was turning or not turning ????

or did he check the high side????
thanks JL

 

[wcsmithiii0911]

Thanks to all for the very direct and professional assistance. I do not have a manifold gauge set so I was using the gauge on the 134a can. The compressor is not turning; the center piece on the pulley I mean. Even when I jumper ed the plug for the switch [unplugged the switch and wired the hot pin to the ground pin]. I have one more check before I contact the dealer. Thank you all, again. Maybe some day it will be my turn to aid another in need.
And YES the Fish House was fantastic -- she deserved it. Putting up with me all these years......

 

[wcsmithiii0911]

Thanks to all of you again. Yesterday I got under and checked the compressor and found that the clutch disc and hub came off in my hand, there was no bolt in it. The shims were still in the hub but I could not tell if the bolt had broken or just come out. This morning I called three local dealers and finally found a bolt, something I could use to find out how deep it should be. Well, there was nothing in the bolt hole, thank goodness. I put the disk and hub back in place (with the shims), loaded the bolt, 1" long 5/16, with lock tight and torqued it to 10 ft lbs. When I cranked her up got good cold air and no squeal. $1.69 sure beats $920.00. Again thanks, you were all mighty good help. Some day it will be my turn to help someone. [133,000 miles and the bolt just comes out, go figure]