230 compact clutch drag

[ab140]

I have a Mercedes 230 compact, 6 cylinder, around 1970 vintage, with a 4 speed manual gearbox.

I have recently replaced the clutch master and slave cylinders and don't seem to be able to bleed the clutch adequately. The clutch will only partially disengage and I can't put it into gear with the engine running.

Does anyone know of any tricks for clutch bleeding on this model or have any other ideas as to what is causing this problem?

 

[slade1]

You may have the slave cylinder up side down. The bleed nipple should point up.

 

[ab140]

Thanks for your suggestion.
The hydraulic pipe comes in at the top (with the bleed nipple at the rear), so it will only go in 1 way.

 

[slade1]

Do you have a power bleeder? Can't remember the name, they hook up to tyre and use air pressure to bleed the system.
The work very well

 

[ab140]

No I don't, but I might have to find one and give it a try.

 

[colinallcars]

No I don't, but I might have to find one and give it a try.

Try bleeding it backwards. Connect a length of tubing to the slave cylinder bleed nipple and lead it up through the engine compartment. Fit a funnel or similar to the end and pour fluid in. Open the nipple and let the fluid run through. You’ll need a helper with a syringe to remove excess fluid from the master cylinder. I’ve used this method successfully when the orientation of the nipple meant it was difficult to eliminate air from the system.

 

[ab140]

I might give that a try.
I have already tried using a syringe to inject fluid from the slave cylinder bleed nipple, but your method could allow me to get a much larger volume of fluid through in one go!

 

[Bellow]

Another method I've heard of is to detach the SC and raise it as high as the hose will allow to encourage any trapped air to escape. The straightening of the hose and general movement of the hose must help in dislodging trapped air bubbles. For sure, pumping an air bubble downwards is an attempt at defying gravity.

 

[colinallcars]

I might give that a try.
I have already tried using a syringe to inject fluid from the slave cylinder bleed nipple, but your method could allow me to get a much larger volume of fluid through in one go!

With a bit of dexterity you can balance it out so that you can move it up and down to help dislodge any bubbles of air.

 

[colinallcars]

Just a thought. Are you sure you haven’t reversed the positions of the feed hose and bleed nipple when refitting?

 

[ab140]

I have finally got my clutch to work by extending the M/C push rod about 10 mm and removing virtually all the slack.

There is no air in the hydraulics and no free play in the clutch mechanism in the bell housing.

I still think that this is fixing the symptom rather than the cause as it worked before disassembly (but with a tiny bit of drag).

I suspect that the pressure plate is not lifting evenly and may not have been helped by me compressing it fully in my press when I couldn't see anything wrong with it?

Anyway, hopefully it will keep behaving itself.

 

[optimusprime]

AB140 For some reason the W123 have two pushrods one longer than the other .