I have a clutch issues which is dragging on and wonder if anyone can offer any experience/advise ?

The clutch pedal was initially sticking in the engaged position. I've changed the master cylinder replaced with a pattern part as that seemed like the most obvious cause. After changing it and bleeding it (using 1 man pressure bleed system off a 15psi tyre) the clutch operated fine, although the biting point was a little low and the clutch felt very 'loose'. However, after around 24-48 hours of use the clutch would go again with pedal sticking down and no engagement of clutch. There is no leaking hydraulic fluid anywhere but on bleeding again found air in the system to bleed out. It would then work for another 24-48 hours before failing again.

My initial thought was the aftermarket pattern master cylinder was cheap, so I then replaced with a second hand but OE full clutch pedal and master cylinder from a breakers. Bled the system again and the clutch felt much better the pedal was heavier and the biting point around half way down so I though problem solved, happy days. However not happy days 😞 again after 24-48 hours the pedal feels really light and the biting point is right down near the floor again.

It's as if it's letting air into the system somewhere, but without leaking any fluid out. Any ideas please on what should be my next move ???

Worth noting - I've replaced O rings and made sure the little rubber cap is in place correctly when attaching the pipe back into the master cylinder each time.

I'm comfortable with any level of repairs myself, just didn't want to pull the box unless it's likely the best move next as i don't know focus's very well at all ... 

1 hour ago, pete10 said:

It's as if it's letting air into the system somewhere, but without leaking any fluid out. Any ideas please on what should be my next move ???

I'd say the seals on the clutch slave cylinder are leaking allowing the fluid to get past them and the pressure is then lost. It's possible that the oil is not escaping from the cylinder and is being drawn back when the clutch pedal is released. Or a small amount is leaking  out of the slave cylinder but is being trapped inside of the bell housing.

Thanks for the response on this 🙂 in that case i think it's gearbox off and new clutch & slave cylinder next. I had pretty much thought I'd ruled anything else out at the easier master cylinder end.

I've read all sorts about the bleeding process being tricky on these leading to clutch operation issues, but as my pressure bleed kit seems to be bleeding the system fine initially (I'm getting clutch operation to begin with, and then slowly losing it) I'm thinking the bleeding process is not the issue either.

Could be a daft question - would a split vacuum pipe going to the brake booster/servo let air into the clutch hydraulic system ?

I've found that, but not sure if it's on a completely separate circuit and has nothing to do with the clutch hydraulics ...

21 minutes ago, pete10 said:

would a split vacuum pipe going to the brake booster/servo let air into the clutch hydraulic system ?

No, the vacuum servo of the brakes is not related to the clutch operation.

You say you bled the clutch using a pressure bleeder?

I replaced my clutch, slave, and master on my Fiesta and bled the same way and I'd lose the clutch completely in high temperatures. Reverse bleed it instead and it should make a world of difference.

I did mine with a giant syringe, hooked it up to the bleed nipple on the slave then injected the fluid until it started to fill the reservoir - it's the recommended bleed procedure for the IB5/IB6 I believe.

as above, reverse bleed.  got me out a jam many a time.  Also, as also suggested, if the slave is on the way out, the new master just ends up putting more strain on the slave and it'll eventually fail.  Had this with a cowboy who did a clutch for me but used the old slave.  Went through 3 master cylinders as pedal would drop over a week then come back when engine / bell housing was warmed up.  Eventually slave failed big time with brake fluid all over the bell housing / driveway.