clutch problems

[CalicoDreams]

me and my buddy just picked up his new car, a 89 240sx. We knew it had a clutch problem so we towed it home. To me it doesn't sound like a clutch disc or anything like that. The guy that had it last said the slave, and master cylinder have been replaced, and the lines also. We bled the system through the little nipple by the tranny, and filled it back up with fresh fluid, then bled the system. We still are not getting any clutch pressure at all. Any ideas? we are trying to get it to work today so we can play with it a bit.

:edit: oh yeah, and that looping line in the clutch or whatever they had (I'm not into imports, the guy was talking about it) has been taken out, and redone. we did find a little leak there but we tightened up the joint there before we flushed and what not.

[slideways...]

the master cylinder gives the pedal pressure, not the slave cylinder.
id say the guy bought a faulty master cylinder, or more likely he didnt bleed the master cylinder before he installed it.

[TatII]

that is not true. the clutch system is a hydraulic system. it needs to be totally sealed for pressure to travel and build. if you have a faulty slave cylinder, your pedal would sink straight to the floor and not pop back up ( mine did it to me on the highway ) if the seals are gone, then fluid would just leak out of the cylinders whether it be the master or the slave. this means theres no seal so pressure is just leaking out.

when you bleed the clutches, you need to bleed both from the master cylinder and the slave. this way you can get every pocket of air out. this would take alot of filling and building of pressure as the clutch initial will feel completely dead and keep on doing it till you start to feel alittle pressure build it up and keep on doing it till you get full pressure back.

[slideways...]

yeah i agree but i was keeping it basic
the slave cylinder's only job is to return the fluid back to the master cylinder. pedal pressure is felt because of the sealed system, but the master cylinder has the piston that pushes the fluid, and the spring that helps push the piston back

[orestes]

lol

[240SXSlideStar]

hahahahahaha

[slideways...]

yeah yeah blow me

[TatII]

Originally Posted by slideways...

yeah i agree but i was keeping it basic
the slave cylinder's only job is to return the fluid back to the master cylinder. pedal pressure is felt because of the sealed system, but the master cylinder has the piston that pushes the fluid, and the spring that helps push the piston back

hahah alright guys enough with the owned pics, i'm not done yet. anyways its not the slave cylinder the causes the return pressure. the slave cylinder is the actual actuator that causes the mechanical motion required to release the clutch. the actual force that cuases return pressure going back to the pedal would be the diaphram spring on the pressure plate going up against the throw out fork pressing back against the slave cylinder.

[mmcleo11]

Getting back to the question at hand, depressing the clutch pedal would allow you to see the slave cylinder pushing the pin out and moving the clutch fork. If this is not happening, something is wrong with your line pressure.
1) fill the clutch fluid canister, the clutch master cyl should be bled by having your buddy put his foot on the clutch and bleed it at the master cyl output line. When the pedal sinks to the floor, tighten up the line, repeat 3 times.
2) top up the clutch fluid canister, bleed the slave cylinder in the same manner as before but using the nipple located on the slave cyl.
Again test to see if the clutch fork moves?

3) If however, the clutch fork moves and you have no clutch dis-engagement, your clutch diaphragm or clutch assembly is faulty.

[slideways...]

Originally Posted by TatII

anyways its not the slave cylinder the causes the return pressure. the slave cylinder is the actual actuator that causes the mechanical motion required to release the clutch. the actual force that cuases return pressure going back to the pedal would be the diaphram spring on the pressure plate going up against the throw out fork pressing back against the slave cylinder.

ok thx for the right info
that makes sense i just thought about it all the wrong way