V50 G/box : V50 2.0D mmt6 clutch hydraulic issue/mystery

[Easy]

I have a 2005 V50 2.0D with a six-speed manual. All was good, until the clutch slave cylinder developed a leak.

Car spec's:
V50 2.0D
Model year: 2005
Engine type: D4204T
Transmission type: MMT6

So, I spent some time on the internet and decided that it was safest to have everything replaced at once.

1st garage visit, replaced: Dual Mass Fly-wheel, friction plate, pressure plate, seals, slave cylinder and master cylinder.

After picking-up the car it soon became evident that the clutch was not bled properly, or so it seemed. After a couple of weeks and several bleeding sessions (carried those out myself), I concluded that it must have a leak in the hydraulics. So back to the garage ...

2nd garage visit, replaced: rubber seal between the hydraulic hose and master cylinder. (droplet of brake fluid noticed on the connection between master & hose)
3rd garage visit, replaced: all rubber seals in the hydraulic hose and the ones connecting to the cylinders. (droplet of brake fluid noticed on the connection between master & hose)
4th garage visit, replaced: nothing (droplet noticed again; seal removed, inspected and reinstalled)
5th garage visit, replaced: master cylinder (note: this is the 2nd new master cylinder, of course the issue remained)
6th garage visit, replaced: complete hydraulic hose assembly and friction plate (friction plate was soaked with brake fluid, resulting in clutch-slip)

Picked the car up today, fairly quickly noticed a changing point of engagement, it goes back and forth (depending on frequency of clutch use it engages at the beginning or the end of the stroke). This is the initial symptom before serious 'sticking' .... so the car is back at the garage (for the 7th time!!!!).

Anyone got any idea on a possible root-cause?
Because I am pretty sure that the garage mechanics are out of ideas; and, so am I.
Thanks in advance!

[padder1956]

if the plate is contaminated the csc is leaking mate

[Easy]

A big thanks for the quick reply padder1956!

Seems like a likely cause (what I don't understand is how the garage mechanics could have missed it).

If so, it seems to me that it is unlikely that the new clutch slave cylinder would have a defect out-of-the-box. If the mechanic compressed it (with a compression tool) during installation, that could explain the malfunction of a new part. At least, from what I have ready online, compressing the csc prior to installation is a big DON'T.

I will call the garage on monday to discuss their plan of approach and indicate the csc as a likely cause. I will post/confirm the 'root cause' once it is determined with certainty.

[padder1956]

some people cannot resist getting them out of the box and testing them that is so funny
to see it i work in a motor factors now the cylinder comes back faulty unlucky i stood
and watched squeeze it a couple of times warranty void
lol Paul

[Easy]

Update: after an additional 2 weeks at the garage; it seems that exchanging the hose between the brake fluid reservoir and the master cylinder has done the job.
It will still take a couple of weeks to completely ease my mind, but after 5 days of driving: all is well so far.