Replacing noisy a/c bearing

Last Saturday I replaced the bearing in the front of the a/c compressor on my HZJ105 as it was noisy, and had been for some 12 months or so. During the routine service and belt inspection I decided to investigate. This particular bearing allows the front pulley and belt drive to rotate with the a/c turned off, so although it's part of the a/c compressor it's always working and thus noisy with the engine running. Because it's not internal to the compressor, no refrigerant gas will escape.

Firstly you need to ascertain that it is your bearing that is noisy, and not the idler / tensioning pulley. This can be done by removing the belt and feeling / turning the pulley and idler by hand, and again by running the engine to see if the noise has disappeared.

If you have found the a/c pulley to be the culprit, refit the belt, turn on the ignition, turn on the a/c (this will engage the compressor and prevent it from turning) and use a 10mm socket to loosen the clutch hub retaining bolt. Remove the belt once again, remove the bolt and slide the clutch away from the compressor, do not tilt the hub downwards otherwise you may loose the washer or shim from inside the splined socket.

In the centre of the pulley you will now see a circlip, this retains the pulley. To remove the circlip you'll ideally need some right angle external circlip pliers and a small flat bladed screwdriver. Once the [pesky] circlip is removed the pulley assembly *should* slide off the front of the compressor, however if it's like mine and some moisture has got in between the alloy compressor snout and the bearing some corrosion may make it tight.

I found that some constant gentle tapping on the pulley with a piece of wood (or soft hammer) was enough to remove it.

On my vehicle there's not quite enough clearance for the pulley to come all the way off before making contact with the fan shroud so I removed the 4 bolts which retain the compressor to the engine so that the compressor could be moved rearwards slightly and the front rotated upwards (actually that's how I got the circlip off without the right angle pliers too ;-)

Once the pulley assembly is off, you'll see the bearing in the centre. It's retained by 6 punch marks in the rear side of the pulley. These can be knocked back outwards with a small hammer and punch, and the bearing then pressed or knocked out. The new bearing is fitted by pressing carefully back into the pulley, the punch marks reinstated to retain the bearing, and the whole procedure reversed to complete the job.

The bearing is a Nachi 30BGS10DST, available from your local bearing supplier for around $20 (but not your Toyota dealer - you have to buy the pulley assembly!). I believe that all the Denso compressors run the same bearing although the pulley type varies between vehicle models (i.e.. 1HZ uses V-belt, 1HD-FTE uses a serpentine belt), thus the procedure should be the same. If the bearing is allowed to seize eventually (eg. lack of lube or foreign ingress caused by off road activities), I can see how the compressor will be instant scrap as the bearing would chew the alloy snout off the compressor.

Hopefully someone will find this of use in the future.

Regards,

Greg Goulden

2000 HDJ105 - with quieter idle

Melb. Au.