Hi all,

does anyone know what type of pulley this is and how it works?

LINK

I have one on my a/c compressor and the centre is stationary while the outer rotates. I have read it's like a shear coupling of sorts to avoid throwing the belt off if the pump seized. It's not a clutch pulley (as listed in the link above) as there are no connections to or near it, just the control valve connection on the back of the compressor.

I'm pretty sure it should all be spinning, any ideas?

Background info on this thread THREAD bottom of pg2 & pg3

Thanks in advance, Stott

quote:

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Originally posted by Stott

It's not a clutch pulley (as listed in the link above) as there are no connections to or near it, just the control valve connection on the back of the compressor.

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No unfortunately it's not an electromagnetic clutch, it's just a shear coupling thingy.

The connection on the compressor is for one of these: LINK This is the only connection to the pump, in these systems the pump runs constantly at a very small displacement so even when the a/c is off the gas & oil circulate to help the seals etc. Rather than a clutched pump which only runs on demand.

It's a clutchless variable displacement compressor

I've worked on clutched ones before and understand the principle but this isn't one I'm afraid.

Cheers anyway
Stott

Just figured it out I think.

Looked at another vRS and the whole pulley spins all the time with the engine regardless of whether a/c is on or not.

When the engine is off it's not possible to spin the centre by hand as it's linked to the outer and therefore the belt. On my car, it never spins with the engine but it spins freely by hand independantly of the outer, so it looks like it's sheared internally, new pulley required, cheers

Stott