1987 760 turbo, 150K w. orig kiki AC --
I need to remove my AC clutch. Recent posts have mentioned putting 12V to the clutch in order to lock it up so the center bolt can be removed. My question: how do I do this?
Is there a connector up on the accumulator or thereabouts that I put 12V into?

The clutch is slipping, and the compressor turns freely w no binding
When I get the clutch off, I'll first see if there s a way to adjust the clutch, then
failiing that I can always buy a new clutch, or pull one. Isnt there a spacer/washer
that the factory uses to set the clutch clearance when new, and can that spacer
be taken out to tighten up the clearances to keep the clutch from slipping?

Any help is appreciated. It is hot here in Silicon Valley, CA
I need to find a good AC shop in the Bay Area,
(south san jose up to redwood city, or across the bay around fremont)

Hi -

I really don't know exactly how to hot wire the clutch on a 740 a/c Diesel Kiki compressor. I have all 240s. This is an estimate.

Usually there is a single wire from the clutch, black or just real grimy, that runs towards the back of the compressor. Somewhere, maybe near the compressor, there should be a connector which can be disconnected, thus isolating the clutch. Then you can apply 12v to the wire to the clutch from whatever is near.

I do have a question about one thing in your post:
"The clutch is slipping, and the compressor turns freely w no binding"
If the clutch is slipping, how can you turn the compressor?

I would try this: With the drive belt removed, hot wire the clutch and then see how the compressor spins. BTW, In my experience the clutch can slip because of a loose drive belt - in a 240 which may not be the case in a 740.

Good Luck,

Bob

:>)

took the belt off and turned the compressor pulley by hand.
Yes, not the clutch pulley but the inner pulley thats connected directly to the compr.
I know the clutch is slipping because visually I could see
it slip- it would engage, then not turn at belt speed. Made a rattling noise at 2000rpm,
after a 90+mph run, the clutch smelled burnt. It was. The AC would blow cold, but
when the rpms got above 2000 rpm, the clutch would slip and the AC would blow warm.
When cold, it would engage just fine. but when hot, slip. So I removed the belt.
Its gonna be record temps this weekend...

Hi:


Disconnect your round connector that connects the Low Pressure Switch wire to the Clutch Wire. use a jumper wire from the positive terminal of the battery to the disconnected wire of the A/C clutch. be careful not to touch anything else. I like to put an inline fuse holder in this jumper, just in case you ground it out. Fuse it for 10 Amps. This will hotwire the Clutch.

If your clutch is slipping badly, I'm not sure this will help. An alternative might be an Impact Wrench on the center bolt. If you can get it in there.

How Not to Fix a Slipping AC Clutch
-- 1987 760 Turbo --

1) Remove the belt. I cut the AC belt off to get it off the pulley, because some bozo rounded off the tension adjusting bolt -it looks like a piece of well chewed bubble gum.
Several days later I bought stripped nut removal tool from Sears.
It's endorsed by Bob Villa, it must be good ;-p .
I haven't tryed it , I'm nowhere near putting a new belt on..

2) Remove the bolt in the center of the clutch-
not much force needed, it's a small bolt. I don't have the 'special' tool to hold the clutch, so I improvised. Sears sells a 'wrench' that uses a rubber strap. I used it to hold the clutch, removed the center bolt. Easy. Some archives recommended jumpering the clutch to lock it in place, but alas, I had already cut the belt. Just as well, the clutch wouldn't hold anyway- it slips.

3) Pull of the clutch from the compressor shaft.
To pull the clutch off, I read the archives and got a massive 7/8 (or 1" bolt) , screwed it into the center of the clutch (there are threads around the recess where the smaller bolt was removed) and attempted to 'screw it in to pull the clutch off'. Duh. first you have to secure the clutch from turning- this time the Sears belt wrench wouldn't hold against the torque of the large bolt. I read the archives again- instead of the 'special tool' to secure the clutch plate from turning, it was suggested that a piece of angle iron with two bolts could be fabbed as a substitute for the spec tool. Another trip to the hardware store. Made the tool, seemed to work, then the 7/8" bolt wouldn't turn anymore. Stuck.
- - - back to the archives - - - The three smallest holes in the front of the clutch disc have threads for ~8mm bolts. By tightening them evenly, the clutch plate pulled off in less than a minute! SUCCESS at Last ! When I inspected the clutch I discovered why the large 7/8" bolt would not turn anymore. It was bottomed out! Arrggh. I should have unscrewed the small center bolt only halfway, then put in the 7/8" bolt to push against it..

4) Tighten up the clutch disc .
It is said that there are washers used to set the clutch gap at the factory, and after the clutch wears, the washers can be removed to restore the proper gap. There is only one washer in the shaft. I removed it. No other adjustment to be found.

5) Inspect magnet coils and wiring.
I have no idea how the remaining half of the clutch and the free spinning double pulley can be removed. Without pulling this, the electromagnet coils cannot be accessed.

6) Jumper the clutch to confirm operation of the magnets.
Yes, the big round connector that plugs into the top of the accumulator (low pressure switch) is the positive circuit that feeds the clutch wire on top of the compressor.
I jumpered the wire to the positive battery terminal. LARGE sparks and weak clutch engagement. Hmmm. Used a inline tap to splice a wire into the wire that comes out of the clutch, on top of the compressor. Now I've got a jumper going directly into the clutch, bypassing the wire that travels along the intake manifold across the engine to the accumulator.

Put the alligator clip on the positive terminal. Big Spark!. The clutch snaps shut. Within five seconds, the jumper wire is so hot that it melts the insulation. Disconnect the jumper!
Crackling sounds from inside the clutch pulley, sounds like the coils are frying.

I assume that the coils have an internal short.
Is that why the jumper pulled such a large current?
The wire to the accumulator is smaller than my jumper, why didn't that wire melt?

It looks like a new clutch is the next step.
The compressor turns smooth, can I get by without a new compressor?

HOW do I get the rest of the clutch off the shaft?

I thought the clutch could be removed without pulling the compressor seal. If I have to evac the freon, and pay for a new R-12 recharge ($90), I might as well buy a new compressor and clutch and do it right, even though it involves a lot more labor.

what do I do now?
I thought this was a one-banana job.