Clutch peddle going down but clutch doesn't work,, looks like the master cylinder or the slave is not working. How do know witch one it is?

Attempt to bleed the system. If no luck. remove the line on the slave and see if the MC pumps fluid out of it. If it does, rebuild or replace the slave cylinder. If it doesn't rebuild the MC. Or just bite the bullet and remove both for a bench rebuild. If you have more money than time, buy new.

As an owner of many 122 models I can assure you this is a common problem. As others have suggested -- just get right to it and rebuild or replace both at the same time unless you find some other reason for the problem (leaky flex hose, for example). On a 122 the slave cylinder is external, visible and easily reachable. Keep those 122's on the road--a great car. Good luck, Dave

With a clutch it could be a lot of things. Since it doesn’t engage, most likely a bad slave cylinder or throw out bearing. Look for slave cylinder fluid leaks on the transmission case near the throw out arm.

Also, listen when pushing on the clutch for noise. Noise and difficulty engaging indicate a worn throw out bearing. More of a long shot is a worn out clutch pressure plate or disc.

The throw bearing always requires transmission removal to replace. I am not familiar with the slave cylinder location in your car. Usually it also requires transmission removal to access. If you need to remove the transmission it then makes sense to do a full clutch overhaul. Throw out bearing, slave cylinder, pressure plate, clutch disc and pilot bearing.

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Will I buy another Volvo??? We'll see....

I do not really have experience with this issue, but my thinking would be -

Are the mechanical parts in good order?

Is the fluid reservoir full?

Check fluid line for rust, or even a leak.

Next I would bleed the system.

My thoughts would be that both the rubber parts at each end have the same wear as they both act at the same time.

I would then dive deep and pick up rebuild kits for the two cylinders. You can compare the new rubber parts to your old ones. With brake cylinder cups, worn edges are sharp and even scored - new cups have a thin square edge.

Then remove the system and rebuild both ends - Make sure you gently hone the cylinders to remove gunk - then reassemble.

You may never have to look at that system again.

I am sure that others might have tips for you.

On most cars, the transmission has to be removed to access the slave cylinder. The master cylinder is below the pedal so it can be overhauled.

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Will I buy another Volvo??? We'll see....