[Vincentnova]

hi there
i have this issue
this is an hydraulic clutch system
this a weekend project still on stand...

when i put it together it was fine , clutch was releasing correctly ( at that time i didnt started the engine yet)


now the clutch wont release ( at this time i already started the engine )

i go under the vehicul , looking at the the clutch plates ,with the help of someone depressing the clutch pedal , i can see the clutch disengaging but quickly re engaging.....??
it look like the pedal half way disengage the clutch ,but once fully pressed the clutch engage again

any ideas here of what it could be ?

 

[johnsongrass1]

Master Cylinder or Slave cylinder leaking past the pistons and back into the reserve.

 

[BogiesAnnex1]

if you haven’t I start with bleeding to make sure no air is in the system.

Bogie

 

[curtis73]

Both of the above replies are where I would look. I would start with the bad master or slave because if there is air in the system it typically will just not move enough as opposed to moving and then falling back.

 

[Vincentnova]

thanks for all your reply

master cylinder brand new willwood

slave cylinder ( generate brand ) new as well

this evening i bled the entire system again....master cylinder out , bench bled , bled the system multiple time with an helper

i got a firm pedal

but the problem remain the same..

soon as I or an helper press the pedal the clutch disengage , pushing the pedal further clutch engage....

from a different window at the bell housing , i looked at the slave cylinder and it look like it is going out..it doesnt come back

i asked my helper to press the pedal and stop soon as i see the clutch disengaging , once the clutch disengaged he stop pressing and hold it there without moving
then i look at the salve cylinder and told my helper to keep pressing , the salve cylinder travel further ( and clutch engage...)

any idea guys ?

 

[curtis73]

New doesn't mean good. I had a brand new (not reman) Exedy slave for a Mazda that was crap from the factory. Wilwood does good stuff, but it doesn't mean it's good either.

An air bubble acts like a spring in the system. The bubble immediately compresses as you press the pedal, meaning it will limit how much the clutch travels. If you have a clutch that is disengaging and then drifting back to engaged, you have an internal leak. The fluid is leaking past an internal seal somewhere in the master or slave. There's just not really any other way around it.

 

[RWENUTS]

What style of pressure plate?
A diaphragm type can over center and act like yours.

A clutch like this.

Clutch Tech Part One: The Pressure Plate, Get a Grip! - Page 3 of 3 - MotoIQ

, Some clutches have two diaphragm springs stacked on top of each other to greatly increase the clamping force. The rivets you see in this picture around the clutch cover…

motoiq.com

 

[Vincentnova]

this is an ls7 basic clutch
it is on a ls truck engine with an ar5 transmission

 

[S10xGN]

Hydraulic cylinders can be forced to travel past their designed stroke which usually blows the seal and causes a big time leak. Could there be a slave designed to leak internally? Dunno. Maybe try adjusting the pedal stop until the clutch just disengages and watch to see what happens...

Russ

 

[Vincentnova]

ive been on it pretty much all day today

im wondering if Im overextending the pressure plate wich could also over extend the finger and diaphragm

because i can see the slave cylinder gong all the way out , and again the clutch disengage before the salve is completely all the way out , and slave cylinder fully out clutch engage

- would it be possible that the slave cylinder goes all the way out even with air or a leak in system ?

- does a diaphragm clutch pressed to far will start clamping again ?


- how much should a centric salve cylinder travel ?

 

[RWENUTS]

I guess you missed my post #7.
A diaphragm will do that.
Nothing like the thrill of the clutch pedal sticking to the floor when the fingers over centre.

 

[Vincentnova]

I guess you missed my post #7.
A diaphragm will do that.
Nothing like the thrill of the clutch pedal sticking to the floor when the fingers over centre.

yes sorry at first i didnt really understand when you sdaid ''diaphragm type can over center and act like yours.''

i build a clutch pedal stop , and now seems fine
i fund a lot of article about ''clutch pedal stop''


hoppefully i didnt damage the diaphragm