clutch cylinder

[jerseyvixen]

any one used a burtons slave cylinder the one on the gearbox input shaft .
i have a problem as the piston does not fully return and leaves the release bearing in contact with clutch fingers .
have pressure bled no better .
changed master cylinder from .625 to .7o no change
thanks

[Steve_D]

What fluid did you use?
Have had owners in the Ultima forum who have used DOT5 on that type of slave cylinder and it melted the seals causing the whole thing to become gummed up.

Steve

[jagracer]

It wont release unless the engine is running and even then the bearing will probably still turn against the forks.

[Mr2Mike]

Either your master cylinder is not fully returning, or the the spacer underneath the slave cylinder is not of the correct height and needs machining down.

Are you getting clutch slip, or will it not engage at all?

Edited by Mr2Mike on Friday 21st May 20:17

[jagracer]

When you fitted it was there any clearance between the running face of the bearing and the clutch forks with it fully retracted?

[perdu]

almost certain to be spacer dimension

Burton sell those spacers in various sizes, I made my own to suit the Midget and type 9 box application

the release bearing is supposed to run against the fingers though but not under tension

[jerseyvixen]

thanks
using dot 4 fluid
bearing has about 7 mm clearance but does not return back and stays on fingers
master cylinder returns back fully

[jagracer]

jerseyvixen said:

thanks
using dot 4 fluid
bearing has about 7 mm clearance but does not return back and stays on fingers
master cylinder returns back fully

So what's the problem, it sounds normal.

[jerseyvixen]

burtons/rally design tell me it wont last if in contact

[perdu]

jerseyvixen said:

burtons/rally design tell me it wont last if in contact

All the evidence I collected when I was planning to "concentricate" the Midget with a Burton Nose unit and a Saab slave suggests that "in contact" is normal

My "National Clutch Components" parts catalogue advises checking with the vehicle manufacturer, seems to make sense!

It says "some vehicles require the release bearing to run in constant light contact with the cover asembly diphragm, where others demand significant free play."

My car had a spate of damaged diaphragms before I changed to concentric and has run for three years now (variable use, sometimes constant sometimes very occasional, always fairly rapid use) and has not damaged the fingers or the bearing and it is running in contact constantly

I checked the condition last October when I pulled the engine and box to repair an oil leak/loose slave cylinder problem. (Do not expect Loctite to work on chromed cap head screws, they are so slippy shiny that the seal cracks up)

[Mr2Mike]

jerseyvixen said:

thanks
using dot 4 fluid
bearing has about 7 mm clearance but does not return back and stays on fingers
master cylinder returns back fully

Totally normal with a concentric slave, most even have a spring in order to ensure this.

[stevieturbo]

would imagine any hydraulic system would have to run "in contact"

WHereas a cable operated system by nature may be able to have a little clearance built in.

That would be impossible in a hydraulic system IMO

[jagracer]

stevieturbo said:

would imagine any hydraulic system would have to run "in contact"

WHereas a cable operated system by nature may be able to have a little clearance built in.

That would be impossible in a hydraulic system IMO

Exactly, with a remote slave cylinder setup you have a return spring on the bearing arm to bring it back, you'd normally set them up to have about 1/16th free play. With a hydraulic one, if it were to fully return you'd have to pump the clutch pedal once or twice every time you want to change gear.