Clutch bleed or faulty slave
 

Hi, I am new so apologies if I am repeating a question asked before.
Volvo S80 2016 manual d4 on 90000 miles.

Losing clutch pressure at pedal. Drops to floor and have to lift with foot and then pump pressure into system, ok for a few miles and then drops again. Absolutely no loss of brake/clutch fluid monitored over 1000 miles whilst I have been on holiday. Just got back (phew, it got me home) and before booking the car into a garage wanted some advise please.

Could there be air in the system and needs bleeding? would be great if it’s as simple as this but I guess this is unlikely as not sure how air as got in with no work having been done on existing system.
I am assuming I need a new slave cylinder but living in hope it’s something simpler / cheaper!

The slave cylinder has been known to fail, afraid you are looking at box out to check it so may as well renew it and the clutch while it's in bits. The dual mass flywheel I would carefully assess before going to the expence of changing but it's a 50/50 thing as it's a box out again job when it fails and with 99k on it how long will it last.

I understand it's a 4 or 5 hour job at volvo with their gearbox cradle, so look at your local hourly labour rate for cost. Go to local garage and ask them to quote for the job or diy, both the latter options will probably take longer than volvo without their gearbox cradle.


Paul.

thoughts
 

I guess it might be a problem with the clutch pedal cylinder, as green vm says the csc is the more likely culprit, not familiar with that D4 engine setup you have there, but on earlier D5 engines you would see some clutch fluid leaking out of the hole at the bottom of the bellhousing, but if the pedal is going to the floor maybe its not the csc ? Dmf s in my experience on the older volvos dont seem to have been a problem my S60 had a csc and clutch replaced while apart, but is happily on 140k with the original dmf and no signs of any problem there...but then its about 10yrs older than your S80 !

If your not losing fluid then my money is on the clutch master cyl by-passing . If it was a slave cylinder fault then fluid would be leaking from bottom of the bell housing

Simpler to change than the slave cylinder as no engine / gearbox lifting or removal.