Can I replace the shims myself to correct the out-of-spec clutch gap?
On my car ('03 xc70) how accessible is the clutch to work on once you get the wheel and fender liner off? Anyone done this?

 

Certainly - I just bend the fender liner back out of the way.
Measure the gap first to make sure your work will probably do something. - You have to unbolt the compressor to be able to get a clutch removal tool onto the outer clutch plate. 4 bolts and move the compressor a couple of inches forward. Then probably just remove all the shims - and measure the gap if you want afterwards, a 2003 will be quite worn. Sometimes on older cars removing all the shims still does not put the gap into spec - but that's the best you can do without a new clutch or compressor. And that's why shops want to sell you a compressor - if they reshim yours and it does not work - you will write a bad review - install a new compressor - it works and you are happy. (poorer but no bad review)

You say "slips". Do you mean clutch stops engaging after it gets above x temperature outside or have been running the car for x time on a hot day? Large gap on the clutch makes it stop magnetically engaging with thermal expansion. It does not "slip", it just does not engage.

 

Yeah, it stops working when I'm in stop and go traffic and/or accelerate hard, and then when I shut it down by the dash switch and drive for a few minutes it engages when I switch it back on. Always works on start-up. I read about the wiretie fix. I'd do that (at 250k) but I cant imagine how you'd get access to do that.
The point is, my compressor works fine, it's just the clutch that's worn, and YOU CAN GET A NEW CLUTCH. Seems dumb to break open the whole system and replace the compressor when that's working. And shops CAN just replace the clutch...

 

Actually, I'd LOVE to find a shop that would just replace the clutch. I wouldn't mind paying for that at all. They're about 100 bucks