My AC compressor clutch bearing was making noise when disengaged so I got a 32x47x18 bearing on eBay for $16.00. In order to drive the car while waiting for the bearing I cut off the AC belt. I also ordered both belts and the AC stretch belt tool from Rock Auto. The main belt I ordered was listed as a Gates K060520 private label close-out for $6.38. The sleeve is marked Hanna "replaces Gates K060520 and the belt is marked K60520H-5060520 Made in Korea. For the AC belt I got a Gates K050272SF, which is listed for VIN 040901 and up and is 705mm OC. My VIN is 422406. The pre-040901 AC belt is 685mm OC.

The bearing replacement was at bit of a struggle, not having a press, but I got the old one out and the new one pressed (hammered) in. I thought I had the hard part behind me, but not exactly.

I fought the new main belt for over an hour and just couldn't get it to go on. The combination of it being a little bit shorter and much thicker than the old one was more than I could overcome. I could probably get it on there if the engine was out of the car and on a stand, but that's not going to happen. I finally gave up and put the old belt back on, which unfortunately doesn't have any markings on it.

Moving on to the AC belt, the Gates stretch belt tool doesn't really fit the crank pulley so you can't clamp it on with the bolt, and even if you could there wouldn't be clearance for the bolt around the top half of the pulley anyway. The pressure from the belt locks the tool to the pulley, so not being able to use the bolt isn't a big deal. So I got the belt on without too much trouble, but it didn't seem to be as tight as I thought it should be.

I started the engine and with the AC off the compressor clutch bearing is nice and quiet. I turned on the AC and the belt started to squeal. I looked at the compressor clutch and it was turning in a herky jerky fashion. The belt was clearly slipping. I ended up removing the AC belt using the tool.

I think I may have thrown out the old AC belt that I cut off, so I don't have the number that was printed on it.

I've been looking at JimEllisMazdaParts.com and they list different main belts for the auto and manual (I have a manual).
L37315909 9U manual
L37215909A9U auto
They are both also identified as 6PK-1325.
And they don't have an AC belt listed.

Anyone have any experience or advise on how to proceed?

 

I am in the midst of changing the clutch bearing as well. Used a 2" section 1 1/4 inch galvanized pipe as a spacer to tap out the old bearing. Put the new bearing in the garage freezer for a few hours, then pulled it out, greased it and slipped into the pulley bore. Then I used a large socket and clamped the pulley and the socket in a bench vise (with wooden plates) and pressed the bearing all the way into the bore. I am still waiting for the A/C belt to arrive from Amazon (Goodyear 4050272 Gatorback)

The main belt is really easy to get on. Insert a socket wrench in the center bolt of the tensioner and push towards the passenger compartment. Then slip the belt on and relax the wrench slowly.