Generic P80 AC clutch shim , bread clip, zip tie thread

[abscate]

My 1999 clutch magnet got weak such that I had to reshim very tight to get it to work. My guess is it eventually touched and the clutch self destructed.

I put a new compressor and clutch in as it was gettting growly anyway

AC was needed this summer and was deeply appreciated

[xHeart]

A/C maintenance time is here.
I'm looking at the zip tie method, checking the gap first.

[xHeart]

A clutch gap check with steel feeler gauge allow blades 0.3mm, 0.5mm, 0.53 to slide in. It takes gentle wiggle to slide in blades 0.55, 0.63mm. The 0.65mm blade does not fit the gap.

Is this clutch gap difference of +0.15 too wide and needs a fix? What's the limit, is a 0.53mm gap too wide?

[abscate]

Spec is 0.3-0.5 mm, so you can up to 0.2 mm difference and be in range.

Note that the bigger gap isn’t detrimental as long as the clutch closes on demand. Once the clutch closes the rest gap is immaterial.

If your AC is cycling well I would not ziptie it, if you make it too tight, it’s quite spectacular when it breaks

[precopster]

I did this on a customer's 1999 V70NA to get him through Summer a few months ago. I used zip ties. Still working today, even though Vida shows a low AC pressure DTC.

[xHeart]

Okay, joining MVS P80 Ziptie Club.

One zip tie at each of the tree rings gaps it evenly. Feeler blade 0.25mm slides in like a knife on apple, while 0.30mm saws in with little resistance. Rotating the disk before zip tie was fluid, after, it grinds a hair.

What to expect since it is NOT known if freon is low?

[precopster]

If AC freon pressure is tolerable to the CCM to turn on the compressor then you're good to go. If freon content goes below threshold it won't fire up the compressor. Best is to put a test lamp on the A/C connector to see if your clutch shim is working properly and that the compressor is firing when commanded by the CCM.

Also you can command the compressor on with Vida ECM Activations even if freon is low if it's a 1999-2000 P80 or a P2.

[xHeart]

It is our 1997 850 NA. The compressor did not kick in -- suspecting freon below threshold.

Haynes says, "Warm up the engine and turn on the air conditioner. The charging process requires the compressor to be running." For compressor cycle off if pressure is low due to low charge. It recommends "pulling low-pressure cycling switch plug and attach a jumper wire. This will keep the compressor ON." -- Is this about applying 12v directly to the single wire connectors clipped to the compressor housing?

For a more thorough job, would renting a manifold and vacuum pump help service the system following youtube procedure and help restore freon, oil, and dye to recommended levels? Also, could it all be accomplished with just the low-side since 850s do not came with high-side?

[jreed]

This is just a little update on re-shimming the AC clutch. I originally shimmed it in 2010 with thin brass shims and had been riding around for years with good AC and no problems. Last week it got unusually hot and the AC kicked off after working for a while -- a classic symptom of a clutch gap that has gotten too large over time and won't allow the clutch to engage when the clutch is very hot. I went off and reviewed the helpful videos made by Robert DIY over the years (rspi here) first. Then I checked the gap and found 0.7 to 0.9mm all around.

Out of spec gap on the AC clutch

I installed new shims, using a stainless steel sheet that was 0.25mm thick and a copper sheet that was 0.15mm thick under the rubber bumpers as needed to get the gap back down below 0.5mm, but not tighter than 0.3mm.

Opening the clutch with a screwdriver and sliding in a stainless shim under the bumper to tighten up the gap.

I found that a 0.25mm thick shim reduced the gap by about 0.5mm and a 0.15mm thick shim reduced the gap by about 0.3mm, but your mileage may vary. After installing the shims, I measured all around with the feeler gauges and got gaps that ranged from 0.3mm to 0.5mm.

Copper shim installed, measuring gap at just above 0.3mm.

I added a little glue after installing the shims to keep them in place. I'm hoping for another decade of smooth running AC with this simple fix.

[xHeart]

It is hard to find a piece of flat stainless steel that thin. Where to find such a material?