why does my clutch's hydraulic system build up "extra" pressure? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

d r i f t swift · 09-26-2005, 05:40 PM

heres the deal. just finished the 5spd swap, took out the clutch dampener box, rebuilt the slave cylinder, using a used master cylinder from the jy.

now the problem.. bled the clutch thought it was fine until i drove it and realized it was slipping. so i jacked the car up to check if the clutch was disengaging all the way..so i backed off the bleed screw on the slave cylinder and the clutch pushed the slave cylinder rod back in. so i was driving the car with the clutch half way disengaged. the next morning the same thing happened. so my question is why the hell does it do that? it builds up "extra" pressure almost instantly if anyone can help me out id appreciate it thanks.

kandyflip445 · 09-26-2005, 05:46 PM

Restricted line, pedal free play or the MC cup seals aren't working right. You could try a new MC and see if it works right.

ranisron · 09-26-2005, 07:40 PM

kandy, what do you mean by MC cup seals? The rounded rubber seal inside the MC cap??

kandyflip445 · 09-26-2005, 07:46 PM

They're the rubber cup seals that are in the cylinder of the MC. Part of the moving assembly.

240Stilo · 09-26-2005, 09:10 PM

Quote:

Originally Posted by d r i f t swift

rebuilt the slave cylinder, using a used master cylinder from the jy.

If you didn't make a typo then that is probably the problem. First of all, seals should be new if you're planing on rebuilding something. Second, using master cylinder parts to rebuild a slave cylinder? I aint hearda dat....

kandyflip445 · 09-26-2005, 11:23 PM

I'm pretty sure he meant that he rebuilt the slave and is using a MC from the junkyard.

d r i f t swift · 09-27-2005, 01:54 AM

well i put in a new master cylinder and that wasnt the problem.. the "extra" pressure wasnt really extra, the slave cylinder somehow was getting stuck halfway out so i replaced the slave cylinder and that seemed to do it. well for now. we'll see what happens tomorrow

orion::S14 · 09-27-2005, 07:00 AM

Typically, if it works fine, then builds up presure as you drive...you have too little clutch pedal freeplay, and need to adjust the rod on the clutch pedal.

Do it 1/2 a turn at a time...keep adjusting, then drive it...if it builds pressure again, add more freeplay, then drive it again, etc...

- Brian

09-26-2005, 05:40 PM	#1
d r i f t swift Zilvia Junkie Join Date: Jan 2004 Location: macramento Posts: 380 Trader Rating: (0) Feedback Score: 0 reviews	why does my clutch's hydraulic system build up "extra" pressure? heres the deal. just finished the 5spd swap, took out the clutch dampener box, rebuilt the slave cylinder, using a used master cylinder from the jy. now the problem.. bled the clutch thought it was fine until i drove it and realized it was slipping. so i jacked the car up to check if the clutch was disengaging all the way..so i backed off the bleed screw on the slave cylinder and the clutch pushed the slave cylinder rod back in. so i was driving the car with the clutch half way disengaged. the next morning the same thing happened. so my question is why the hell does it do that? it builds up "extra" pressure almost instantly if anyone can help me out id appreciate it thanks. __________________ rip bobby.. you will be missed..

09-26-2005, 05:46 PM	#2
kandyflip445 Post Whore! Join Date: Sep 2002 Location: Arden, NC Age: 40 Posts: 4,460 Trader Rating: (1) Rides Gallery: kandyflip445 Feedback Score: 1 reviews	Restricted line, pedal free play or the MC cup seals aren't working right. You could try a new MC and see if it works right. __________________ My 240 vBgarage

09-26-2005, 07:40 PM	#3
ranisron Zilvia Addict Join Date: Aug 2003 Location: Bloomington, IN Age: 43 Posts: 766 Trader Rating: (0) Feedback Score: 0 reviews	kandy, what do you mean by MC cup seals? The rounded rubber seal inside the MC cap?? __________________ U13 and S13 zilvia members are friendly

09-26-2005, 07:46 PM	#4
kandyflip445 Post Whore! Join Date: Sep 2002 Location: Arden, NC Age: 40 Posts: 4,460 Trader Rating: (1) Rides Gallery: kandyflip445 Feedback Score: 1 reviews	They're the rubber cup seals that are in the cylinder of the MC. Part of the moving assembly. __________________ My 240 vBgarage

09-26-2005, 11:23 PM	#6
kandyflip445 Post Whore! Join Date: Sep 2002 Location: Arden, NC Age: 40 Posts: 4,460 Trader Rating: (1) Rides Gallery: kandyflip445 Feedback Score: 1 reviews	I'm pretty sure he meant that he rebuilt the slave and is using a MC from the junkyard. __________________ My 240 vBgarage

09-27-2005, 01:54 AM	#7
d r i f t swift Zilvia Junkie Join Date: Jan 2004 Location: macramento Posts: 380 Trader Rating: (0) Feedback Score: 0 reviews	well i put in a new master cylinder and that wasnt the problem.. the "extra" pressure wasnt really extra, the slave cylinder somehow was getting stuck halfway out so i replaced the slave cylinder and that seemed to do it. well for now. we'll see what happens tomorrow __________________ rip bobby.. you will be missed..

09-27-2005, 07:00 AM	#8
orion::S14 Nissanaholic! Join Date: May 2003 Location: Orange Park, FL Posts: 1,666 Trader Rating: (0) Feedback Score: 0 reviews	Typically, if it works fine, then builds up presure as you drive...you have too little clutch pedal freeplay, and need to adjust the rod on the clutch pedal. Do it 1/2 a turn at a time...keep adjusting, then drive it...if it builds pressure again, add more freeplay, then drive it again, etc... - Brian __________________ www.KA24DEvelopment.com