I had a 2002 Jeep Liberty come in with the complaint that the a/c will stop cooling after about thirty minutes of driving. The customer stated that the a/c would start working again later in the day. The first step was to duplicate the complaint. The easiest way I have found to replicate this type of problem is to starter the engine, set the a/c to max cold position, recirculation on and the blower set on low with the windows up and the doors shut. This forces the a/c to be cycled on and off many times in a short amount of time. After about twenty minutes of running the vehicle as described I noticed that the compressor had stopped clicking in and out. I went over to the vehicle and observed that indeed the a/c clutch was no longer being engaged. I grabbed my trusty cut off broom handle and tapped the face of the clutch hub and the a/c started working again as designed. Diagnosis of excessive air gap in the a/c clutch assembly. I forgot to take pictures of this, so the pictures you see are just for demonstration purposes as the new clutch assembly has already been installed.
Care should be taken while doing this as you are actually going to be touching a moving piece of metal with a lot of power behind it. The movement should be a quick jab, meaning tap and pull back quickly.
The first step in this repair will be to remove the belt. I have a special tool for this but a wrench and a little power will do. I should point out that the belt does not have to be removed, if you are only going to be checking the thickness of the shim and the possibility of adjusting the air gap. I had already done that and knew that the clutch assembly had to be replaced.
After the belt is removed the front nut will need to be removed. I am holding the clutch hub with a special wrench for this purpose.
A screwdriver or a flat bar can be placed between two of the round discs as shown as a substitute for the proper tool.
Once the nut is removed the clutch hub can be removed. Firmly grasp the edges of the clutch hub and with a wiggling back and forth motion pull the clutch hub off.
If it is difficult you can use a couple of flat pry bars and gently pry the clutch hub off using even pressure. This is not the proper way but one cannot afford all of the appropriate tools needed. BE VERY Careful if you use excessive or uneven pressure during this step the compressor shaft will be bent and the compressor assembly will have to be replaced.
I will normally only use the pry bar method as a last result and prefer to just take my time and use my hands. Of course I do this every day for a living and I may have a little more strength in my hands as a result.
Once the clutch hub is free, slowly remove it and check for the presence of shim washers. This one had one very thin shim. This is a critical point to check. If the shim or shims are fairly thick then they can be removed or adjusted to reduce the amount of air gap between the clutch hub and the clutch pulley. If you can simply adjust the gap down and reinstall the clutch hub, you will fix the problem for several years usually.
As mentioned earlier the shim was pretty thin and after examining the grooving in the mating surfaces I recommended replacing the assembly. The vehicle was low mileage and the customer intended on keeping the vehicle for at least three more years and did not want to take any chances of the a/c not working with summer approaching.
The next step is to remove the pulley bearing snap ring with the appropriate tool.
After the snap ring is removed the pulley can usually be pulled off by hand or by gentle prying with two small pry bars. This was not working too well for me so I had to use a puller assembly.
I also found that in order to use the puller I would have to remove the cooling fan assembly. Which requires removing the top bracket that covers the radiator. Sounds bad but it was actually pretty simple. First I removed the two center bolts that hold the bracket to the hood latch assembly.
Then I removed the two screws on the right and left sides. Note that the screw in the right side of the following picture does not have to be removed. The other screw that does need to be removed is out of the picture to the far right at the edge if the fender.
Removing the screw in the far corner.
With all of the screws removed I could lift the long bracket far enough out of the way to pull the cooling fan out.
There are two screws that hold the fan assembly to the radiator, that have to be removed and then the assembly has to be pulled up and wiggled past the hoses. I had to push the upper hose in a little to get the bracket past it.
The fan is almost out.
Now it is out and on the floor. You can see the two upper brackets where the bolt as go through to attach it and the two lower brackets that slide into clips in the lower part of the radiator.
Now I installed my puller assembly and removed the pulley from the compressor.
Now the clutch coil has to be removed.
Using snap ring pliers I removed the snap ring from the compressor hub that holds the coil in place.
With the snap ring removed, I next removed the harness retaining screw at the side of the compressor.
Disconnected the harness by first depressing the locking tab on the red clip.
Then I pushed the red clip back until it was flush with the edge.
This allowed the retaining clip to be depressed so that the connector could be separated.
With everything undone I removed the coil assembly.
I wiped the dirt and dust from the hub and positioned the new coil. There is and alignment dowel on the coil and a corresponding hole in the hub.
Installed the new snap ring, flat side down.
Secured the harness to the compressor and connected the wiring.
Next the pulley had to be installed. This is a little tricky, if the pulley will not slide on by hand. Which of course this one would not. Pressure must only be placed on the inner bearing race or bearing damage will result. Ideally a specialty installing tool would be used that uses the shaft to pull the pulley onto the hub. I don’t have one and you probably don’t either. So I used an alternator pulley that has a hole to clear the shaft, a relief to clear the hub and a shoulder to support the inner bearing race. Many times I will sort through a bunch of sockets and find one that will work.
I positioned my adapter into the compressor pulley.
Positioned them on the compressor hub and gently tapped into position.
With the pulley fully in place
I installed the new snap ring, flat side down.
Now the clutch hub. I had to play with the shims to get the desired spacing. I could not find a specification on the air gap so I went with experience and set it between .010 and .015 which is the average between most manufacturers.
Installed the nut and tightened to 10.5 ft lbs according to the specifications that I did find for this vehicle.
Reinstalled the belt and the job was done.
I did notice one very important thing that if overlooked would simply ruin your day. The screws that hold the radiator fan to the radiator are shorter than the screws that hold the bracket to the vehicle. BE VERY CAREFUL NOT TO USE THE LONG SCREWS TO HOLD THE FAN TO THE RADIATOR. THE RADIATOR WILL BE DAMAGED.
A reading of 40 psi when the system is not operating would indicate either a low charge or an outside air temperature of 30 F. If that reading was taken when the relay was bypassed that is a different story.
Hi Sparky,
My friend has a jeep cherokee 2003 straight 6. The air conditoner does nothing when turned on. i checked the low side pressure , which was at 40psi normal for the ambient temp.
I bypassed the relay and everything worked fine.
Any ideas?
Thanks,
Rob