Hydraulics driving me mad

[jp15]

Hi all

I have a 2005 Jazz.

Last week out of the blue, when I try to change gears, it won't go into any gear. Pump the clutch for 1-10 minutes, and it will start working again.

So far the garage has checked for leaks (none), changed the clutch fluid, changed the master cylinder (still same issue), changed the slave cylinder (still same issue but now it randomly grinds when I change gears). They don't think it is the clutch or the gear box itself. Neither does the local dealership. But they have no clue what is wrong and why it suddenly does it. The guy who fitted the slave drove it round yesterday no problems then I am in it for a few miles and bam, back again.

Any ideas please?

[Jocko]

Another thread here deals with the clutch damper and how difficult it was to bleed. Sounds like that may be the issue. Could even be the damper leaking.

[culzean]

Could be a problem with diaphragm or too much free play in the release system.  Clutches last a long time when used properly,  but many people ( including my brother and sister-in-law ) ride the clutch when stopped on a hill rather than pull handbrake on,  this wears the linings and is more likely to result in slippage rather than dragging,  but wear in clutch release bearing can cause dragging. 

All that garage people do these days is change parts in the hope it fixes the problem, their experience seems minimal and unless the OBD gives them so code they are stuffed...

[Jocko]

Pumping the clutch to cure it suggests hydraulics, rather than something mechanical, to me.

[sparky Paul]

Pumping the clutch to cure it suggests hydraulics, rather than something mechanical, to me.

I agree. Air in the system, or master cylinder.

[culzean]

The slightest bit of air in the system may just highlight lost motion in the system anywhere between clutch pedal and clutch release bearing. If the release fork, bearing or even clutch pedal pivots are worn ( 2005 car ) or too much free play in pedal will highlight problems that a bit of air may not cause on its own if everything else was fine.

[sparky Paul]

The slightest bit of air in the system may just highlight lost motion in the system anywhere between clutch pedal and clutch release bearing. If the release fork, bearing or even clutch pedal pivots are worn ( 2005 car ) or too much free play in pedal will highlight problems that a bit of air may not cause on its own if everything else was fine.

Not so sure. Very small amounts of air normally not affected by pumping, the action of which breaks up bigger bubbles that have coalesced when the fluid stops moving.

[Jocko]

I agree. Air in the system, or master cylinder.

Master and slave cylinders have both been changed. That just leaves the Clutch Damper to replace or bypass.

[sparky Paul]

I agree. Air in the system, or master cylinder.

Master and slave cylinders have both been changed. That just leaves the Clutch Damper to replace or bypass.

In that case, I would have a go at pressure bleeding.

Alternatively, try rapid pumping before immediately opening the bleed nipple and repeat, several times.