CLK 230K Clutch....... Trouble????

[Rukka]

Hi everybody,

Just joined the forum and hoping for a bit of advice please.

My dad has just bought and collected a 51 plate CLK 230k Coupe. All seems ok apart from a bit of a wierdy on the clutch.

I test drove it for him at weekend and all was fine.

Today he tells me that after driving around all day in it the clutch seems to play up at times as follows.......

When driving (any gear) and resting foot on clutch pedal (as most people do) - after a certain time (not constant) the pedal will "drop" about 2 inches!!!

It still works fine and comes back to full feeling after a couple of presses. The biting point seems to be the same as well.
He also said that on one occasion only the pedal stuck and he needed to lift it back up with his toe. It did'nt do this when I tried it but did seem to drop frequently - not at first but more and more as I drove it further.

Just wondering if anyone has come across this before? This is the first Merc any of us have owned so have no other experience.

I am technical and know how things work but not sure of the layout of the clutch system on this CLK.

I believe it to be a hydraulic system so;-

1) Can it be bled?

2) Is the slave cylinder external to the bellhousing?

3) If so is it easily accessable?

4) Anything else it might be?

My initial thoughts are poor fluid - although the brake fluid should have been changed as part of the service I doubt very much they will have bled the clutch through as well so we have potentially 5 year old fluid in it - getting hot - breaking down??

does this sound feasable?


Cheers all

 

[Ian B Walker]

1) Can it be bled? -Yes

2) Is the slave cylinder external to the bellhousing? - Yes

3) If so is it easily accessable? - No

4) Anything else it might be?

My initial thoughts are poor fluid - although the brake fluid should have been changed as part of the service I doubt very much they will have bled the clutch through as well so we have potentially 5 year old fluid in it - getting hot - breaking down??

does this sound feasable? - Yep


Cheers all

Hope this helps

 

[Dieselman]

Master cylinder is duff, needs changing!

p.s. DO NOT DRIVE WITH FOOT ON CLUTCH PEDAL. It causes heat and wear.

 

[Rukka]

Just a quick update on this -

We bled the clutch at the weekend and all now seems to be OK.
The fluid that came out of it was really black and manky so looks to have degraded.

For those of you that are interested the Clutch Slave cylinder is just inside the gearbox bellhousing. It can be accessed by removing a rubber (oblong) boot that covers it. If you lie under the car it is on the O/S of the gearbox.

By the way - does anyone know where we can get a decent workshop manual for the CLK ?

Cheers

 

[Dieselman]

I can't see how bleeding can restore an intermittent fault. I suspect the master cylinder seals are not working properly and you have fixed these by cleaning dirt out whilst bleeding the fluid.

I for one won't be surprised if this fault returns.

Another alternative is that by riding the clutch your father has overheated the fluid causing air bubbles, but I doubt it.

 

[Rukka]

Another alternative is that by riding the clutch your father has overheated the fluid causing air bubbles, but I doubt it.

I doubt it too.

Like I said though - the brake fluid should be changed every 2 years, there is no mention of renewing the fluid in the clutch line!

It makes perfect sense that if the manufacturer recommends changing brake fluid at 2 years then it obviously degrades, and by that reckoning then the fluid in the clutch line will be degraded also.

I actually found (in the Merc Tech info) the same sort of fault with clutch dropping and sticking part way down when driving at high altitude - Remedy advised is to bleed the clutch.

Anyway - still working as it should and thanks for all your help.