My dash A/C compressor clutch coil shorted out so I decided to see if I could replace it and save me the expense of having a repair shop purge the system, replace the entire compressor assembly and then do a recharge.
So my first challenge was finding the right clutch. I used the truckerac.com website. They have a very complete catalog that you can use to find the correct part. As it turns out, it was not a straight forward task. I think that sometime before I bought the coach, the clutch was replaced. I think the original clutch had a diode and the replacement did not but they installed the replacement and left the diode in the wiring harness. So after a lot of searching, I did the same. The clutch was just over $100 delivered. The rep at truckersac.com was very helpful with trying to pick the correct one.
I found the service manual for the compressor on a link on Foreforums. Source for dash air compressor? (http://www.foreforums.com/index.php?topic=24177.msg189349#msg189349)
You can buy a removal and install tool kit but it was several hundred $$. I made a tool and used some others that I had or could borrow.
Picture 1 shows the parts that you get with the clutch. It includes the armature, pulley, coil, attaching screws, bolts, snap ring and spacer washers.
The first trick was to remove the center bolt. I used a bar clamp to hold the armature while I loosened the bolt. Then I had to make an armature puller. I used a piece of scrap steel and some screws. See pictures 2 and 3. The center bolt has a nut on the other side and lets you push against the center bolt hole. I found I could turn the 3 outside screws about 1/2 turn and then tap on the steel plate to pull the armature. It took a little patience but it did work slowly but surely. Make sure you save the spacer washers when you remove the armature. I also used PB Blaster before I started.
I then removed the snap ring and used a standard pulley puller to remove the pulley.
The coil is held on with 3 screws. I managed to strip one screw head so had to go buy a screw extractor at Lowes. It worked very well.
Assembly was just the reverse. I borrowed a torque screwdriver to attach the coil to spec, and the pulley went on by hand pressure. I installed the new snap ring. Photo 4.
The armature went back on using the two spacer washers that were on the old pulley and I checked the gap between the armature and the pulley. It was within spec. I again used the bar clamp to hold the armature while I torqued the center bolt to spec. Photo 5.
I connected the electrical for the coil, reinstalled the drive belt and I was done.
I did find that at some point the air hose from the air filter to the air filter minder had been torn by the compressor adjusting bolt. I repaired that. I also found that the two coolant lines that ran through a bracket on top of the compressor were starting to chafe so I installed some rub guard material. See photos 6 and 7.
I went to my local Goodyear service place and they checked the system and added 2 lbs of refrigerant. I know I have a slow leak but it is easier and cheaper to top it off once a year than to chase down the leak. The labor rate at Goodyear was $90, a lot less than Cummins coach care and I was able to stand right with the tech while he worked. I was in and out in under and hour and saved 1.5 hours of travel time.
Hope this helps someone else. Any questions, let me know.
Rich
Have them add dye to system at next recharge. Will show up leak using a black light. That is how the shops all find the leaks
I have dye in the system and think I know where the leak is. The question is do I want to risk damaging the condense during the repair process? Answer--not right now.
Rich