Replacing the AC bearing

This is the procedure for replacing the air condition compressor bearing in a D5244T diesel engine. The procedure will be the same for adjusting the gap distance of the AC magnetic clutch. This procedure could also apply to other types of engines.

Start with disconnecting the battery.

To get enough working space you should first remove the following:

• Engine cover
• Big hose between intercooler and engine
• The engine and transmission computers with casing (you need a special tool for removing the computers)
• Serpentine belt
• Servo pump and bracket
• Alternator

Now you should have access the AC compressor fairly easy. Remove the four bolts holding the compressor (two on the top and two on the bottom). Lift the front end of the compressor up as high as possible and put some support under it.

Screw a couple of M8 bolts into the AC clutch plate and use as counterhold when removing the center bolt.

Remove the clutch.

One way to do this is by using three M8 bolts in the clutch plate. As you tighten these bolts, the clutch will be pressed outwards.

Another way is to use two or three bolts together with a sliding hammer to hammer out the clutch.

Careful when you remove the clutch plate, so you don't loose any of the shims inside. I recommend putting something under that may catch the shims if they fall out.

Remove the center lock ring. Then use a puller to remove the pulley, as in the picture.

Careful when you mount the puller on the pulley so the puller don't pull on the magnet inside the pulley.

Take a picture of how far the old bearing is pressed inside the pulley. Press out the old bearing and press in the new one to the same position (press only on the outer race when installing the new one).

Clean the pulley and the magnet. Mount the pulley on the compressor (remember the shims and the lock ring). Use the center bolt to press the pulley fully in place.

Now you must measure the gap distance between the pulley and the drive plate. It has to be 0.3-0.5 mm. If it is outside this specification you have to remove the pulley and adjust by adding or removing shims.

Another thing is that if you experience dragging noise or that the pulley is not rotating freely - this means that you have bent the magnet plate when using the puller to remove the pulley.

If that is the case you have to remove the pulley again, and then the magnet (3 screws). Carefully use a bench vise to bend the magnet plate back. Then remount the magnet and pulley.

Now you can just mount everything back together by repeating the previous steps in reverse order.