neonglh

iTrader: (42)

So about a month ago, I had STM put a car of mine back to stock, including a full A/C system off of another car. Last night, I went to my buddy's house where he has all of the proper tools to fill the A/C system correctly, so here is what we did:

1. Vacuum out the entire system to remove moisture
2. Test for leaks for 5 minutes (found one TINY leak, tightened the bolt, fixed it)
3. Pulled vacuum for half an hour, to make sure there is no moisture in the system
4. Hook up a new bottle of R134a and start to fill
5. Turn the car on once the pressure reached 90 psi, to kick the compressor on

This is where the problem started, the A/C compressor never kicked on. So, we first checked the wiring, the pressure switch, and everything is hooked up correctly. Using a test light, we made sure that the compressor clutch is actually getting power, when we press the A/C button in the car, and it does indeed get power. We then tried manually jumping the clutch to the battery, and it still won't engage.

After carefully looking at the clutch try to engage, we can see that it moves about a 1/32" - 1/16" upon engaging, but it is just not enough to begin to spin the compressor, it never fully engages.

I was hoping that may be it was stuck, so I gave it a few whacks with a deadblow to maybe free something up, but it didn't change anything.

So, is this a tell-tale sign of the A/C clutch being messed up? Has anyone replaced the clutch before, or do we have to replace the entire compressor on an Evo? Most cars they just sell the clutch and tools at the parts store.

I will have STM take care of this, but I want to be armed with the info so that they are properly prepared. Thanks everyone!

-mark

evilempire18

iTrader: (3)

Same thing with mines. With the AC on i would have to give the clutch a light tap but once it cycles i would have to tap it again. I called the dealer and did some searching online but the clutch is not sold separately. Trying to find a rebuilder

barneyb

https://www.evolutionm.net/forums/ev...c-problem.html

neonglh

iTrader: (42)

Good information, it could be a shim. I wish I knew the travel of a good compressor clutch to see if mine is the right distance (just too far away) or not. I will investigate further.

roro4g63

Well, I just fixed mine. It had the same problem you are describing. While diagnosing the AC system, I had good hi/lo pressures. Got good voltage to the compressor. Pulled the bumper off to fix my lower lip and ran the car.

I immediately noticed that the clutch (the outer part--3 circles--on pulley) was not moving when I turned on the AC. I took off the clutch, and noticed it had a shim on it. I removed the shim and placed the clutch back on. Started the AC and it engaged no problem. It has been a week and the AC is still working.

Hope this helps.

evilempire18

iTrader: (3)

i will try the same and let you guys know. Did the shim had a PN on it?

neonglh

iTrader: (42)

I actually just took my bumper off, and hit the clutch while the car was running (a/c turned on), and the clutch engaged! I then turned it off, turned it back on, and the clutch engaged fine. I wonder if it was just frozen from not being used or something? Well, that's a relief!

-mark

justastockevo

iTrader: (1)

MR315936 a/c service kit

is that this thing you're talking about?

evilempire18

iTrader: (3)

^^^ Yes sir you are the man! Thank you

190hpkilla

iTrader: (19)

You need to shim the compressor clutch properly.

From what it sounds you need a thinner shim. Dealer usually has these in stock. Take the one you have with you and get few sizes down. The best way is to use a MIC gauge to check clutch engagement but you can do it by eye.

Right now the shim is too thick, start going down in size. If the shim is too thin the clutch will engage very abruptly, you don't want that. Find a perfect fit. If you use no shims you can burn out the clutch completely.

Good Luck!

justastockevo

iTrader: (1)

repair kit mentioned above includes different sizes of shims.

justastockevo

iTrader: (1)

also, factory service manual details the repair process.

evilempire18

iTrader: (3)

So the clutch wear’s around it? I would think after a while the shim would get thinner but it seems to be the opposite. That would explain why roro4g63 was able to just remove it and it worked but I would image that it wouldn’t last too long.

meckert

iTrader: (11)

So help me understand---is it the center bolt that needs to come off ? Then where is the shim? Someone else or I read in another threat said this could be done without removing the belt.. Pls share in brief the process and location of what needs to be done to find, check and replace these shims pls...thx.

evilempire18

iTrader: (3)

http://www.evoscan.com/manuals/Evo9/GR00004600-55.pdf REF PAGE 113
Complements of justastockevo