hyd clutch slow to return , experts please

[hermetic]

length of the master cylinder connecting rod could be critical! if it is not allowing the recuperating hole in the piston to open to the fluid reservoir thats the problem! set up on the bench you wouldnt see it!

 

[steveo3002]

length of the master cylinder connecting rod could be critical! if it is not allowing the recuperating hole in the piston to open to the fluid reservoir thats the problem! set up on the bench you wouldnt see it!

its fixed /nothing adjustable although i have pondered if i can make it adjustable

any suggestions how to see if its allowing this hole to work properly?

 

[hermetic]

disconnect it from the pedal and see if it returns more? Can you swap the rods over and fit the shorter one to the new master cylinder?
when the Mcylinder is in the rest position the hole is open to the reservoir, the first few mm of travel close it off, and the piston must return fully to open it again or it will be trying to draw a vacuum in the fluid.
Phil

 

[steveo3002]

the pedal has it pulled to max travel once its popped back

the different length rods are with the slave

 

[hermetic]

ok that shouldnt make a difference..........................or would it? there is a possiblity that the slave is returning to its minimum rest position and the fluid is holding the M Cylinder piston back, try swapping the slave cylinder rods, it might work! I am running out of ideas, but it is a simple thing which shouldn't give a problem yet something is causing it!

 

[hermetic]

is there a return spring on the slave cylinder? faulty new flexy pipe?, does the pedal pop up if you apply pressure to the slave cylinderif you can?

 

[steveo3002]

i have in the past swapped the slave rods over , it made little difference or if it did made the bite point lower

slave does not have a spring

tried several pipe combos all same , others are running this brand with no comments

cannot touch the slave in situ

 

[hermetic]

Buggr!

 

[steveo3002]

one other thought/question , the orig hose is no longer available unless i want to pay £80 for a ropey looking used one , but its a combo of hardline,flexi then a coiled hardline , im wondering does that coil giving it another foot of pipe make any odds

mine and most people use a braided flexi to replace it all now

 

[harveyp6]

I think the coil is either to combat vibration, or if it going between two different mounts to allow for a little movement depending on the application.

 

[PhillipM]

It's to add some inertia to the moving fluid, helps damp out chatter or vibration on engagement, and stops you getting unwanted NVH - it's basically a tiny fluid flywheel. The inside of hydraulic engine mounts has something similar in function.

 

[steveo3002]

It's to add some inertia to the moving fluid, helps damp out chatter or vibration on engagement, and stops you getting unwanted NVH - it's basically a tiny fluid flywheel. The inside of hydraulic engine mounts has something similar in function.

so wouldnt adding inertia move a bit more fluid and do what i want ? maybe?

not sure if that rubber is fatter than 3/16 bore , sort of looks it , i could make each end from brake line and order a custom flexi or find a brake hose to use as a flexi ?

 

[steveo3002]

right , had it out for a 2.5hr jaunt tonight , after a while im getting the occasional normal pedal , maybe one in four is normal , others same as before , no pattern to it , wild pumping on the pedal makes no odds , and tried it with no cap on the fluid tank

question - should pedal up be pulling the master rod to full extension? theres no pedal stop and never was so its pulling on it as far as it will go , i often wonder about seeing if i can make an adjustable stop

 

[m_c]

only in pictures its fairly rare here being a lhd one

To go back to this reply, LHD/RHD should have a similar setup in terms of pedal heights/stops.

Even if you can find a RHD to compare and check for anything missing, it'll give you a good idea of what you should be looking for.