A Horrendous Squeal A/C

[HoneyBadger]

I noticed a squeak on startup that gradually turned into a whine then a full on ear piercing squeal. The sort that turns heads at 50 metres. I stuck my nose under the bonnet a few times trying to work out what it was and ended up at the front left (from drivers view). A small spray of water led me to believe the A/C compressor was the culprit. I could easily turn the clutch on the pulley so reckoned it wasn’t the actual compressor but more likely the clutch or pulley bearing. I sourced a new clutch and bearing from Germany and allowed a Saturday morning to change it over. I’d found a few videos on various Nissans but not the D40. From the top wasn’t really an option without removing the fan and cowl so I opted for a wheel off, arch liner out approach which gave me good access to the area albeit at 90 degrees. I should probably mention at this point that my climate control hasn’t worked due to a leak for at least two years so there is no gas in it. After fumbling around and getting my phone in to take a front on picture of what I was working on I got my 5mm Allen key in there and removed the centre bolt. Cracked the belt tensioner front nut then the adjuster and removed the belt. After tapping the pulley every way it wasn’t budging. Another photo showed me a large retaining circlip holding the pulley in. My circlip pliers didn’t have the reach to get it and even if they did, getting it back in was going to be impossible. Two small bolts held the AC pipes in place so they came out followed by four bigger bolts that fix the compressor to the engine. Bit of a wiggle and the whole thing was in my hands and being carefully extracted between the inner wing and an intercooler pipe. If you need to change the pulley this is by far the easiest way to do it. Once out it was easy to see what was going on. Where the AC hadn’t worked for so long, the clutch face had a glaze of rust on it which would rub on the magnet at low RPM. I was committed by this point having spent £60 on the new parts and several hours removing the compressor so continued. One circlip off popped the pulley off with relative ease, a second one done the magnet. A decent set of circlip pliers would have helped enormously but I combined mine with a screwdriver and managed. There is a locating simple on the compressor to help you align it when reassembling. Anyway… I put it all back together and at this point found the five shims I had seen in a video. These are what give the tolerance between the clutch and the magnet I left them on the shaft and reassembled everything on the bench. A quick spin of the clutch and I heard metal on metal which I just knew was going to be amplified X1000 at 800RPM. I needed an M12 washer to set the tolerance. This could have quite easily been done in 10 minutes by simply removing the 5mm bolt, clutch and shims then adding the necessary amount of washers to give clearance.
So… if you have a squeal and work out it’s the compressor clutch, that’s all you need to do!
Put it all back together and started it up with anticipation… no shriek!
Hopefully I save someone many hours.