'pump up' clutch pedal issue - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

ProjectPanda13 · 09-19-2014, 06:27 AM

I have been having an issue with 'pump up', very much like what DSM encounter with their clutches. Before driving, the clutch pedal is soft and engages low, but as I drive the pedal becomes stiffer and the engagement point moves higher up. When I adjust the pedal lower, like what the DSM guys do, I can feel the pressure release. But if I adjust it too low, I am not able to get into gear.

All this happened about a year ago when I did a clutch replacement. I installed a ClutchMasters FX350 along with a their lightweight steel flywheel. I also installed new pilot and throwout bearing, not to mention arp flywheel bolts. After the install, I had to adjust the clutch pedal further out since I couldn't get into gear. The next morning, I drove the car to work and I first encountered the stiff pedal. I played with the adjustment for a week before finding a decent length that didn't allow the pedal to get too stiff, but still stiffer, and drove it til now. I also have to pop the clutch pedal sometimes to be able to get into gear. I also installed a Nismo slave cylinder to see if it helps, but it didn't

Last night, after a long drive in traffic, my pedal lost all pressure and I had to pump the pedal multiple times to get pressure and also adjusted the pedal to the end of the rod. I made it home but with difficulty. I rebleed the system and have been able to drive it, but have to pop the clutch pedal more often now.

Any idea what it could be? I am going to attempt to replace the master cylinder to see if that will solve the problem. Anyone experience this on their car?

Sorry for the long explanation.

Thanks,
-Dave

Rayne · 09-22-2014, 04:59 AM

Is the clutch line coming off of the clutch master cylinder connected to the: A) dampner box or b) directly to the clutch slave cylinder?

ProjectPanda13 · 09-22-2014, 10:44 AM

The line goes through the damper box. I am hoping to remove it this weekend and see.
-Dave

spiegel420 · 09-28-2014, 08:11 AM

Air. That damper box is a pain to bleed. Remove it, bleed it, done.

***FaLKoN240*** · 09-28-2014, 10:12 AM

I would've thrown the dampener box away when I changed the slave.

In fact, that's what I did when I changed my slave cyl out earlier this year.

ProjectPanda13 · 09-28-2014, 01:06 PM

Yea, I should have at the time. But I had this pump up problem when I first installed my clutch without opening up the system, so I didn't think air was an issue. I haven't had time to do my clutch master cylinder replacement this weekend liked I had hoped. So hopefully, I can free up some time this coming week. I'll, definitely remove the damper box also. I'll keep every posted. Thanks.
Latez,
-Dave

ProjectPanda13 · 10-20-2014, 08:54 AM

UPDATE:

So I replaced my clutch master cylinder and removed the damper box. This has solved my clutch pump up issue. However, with the clutch master I had to adjust the rod all the way out to the end to get enough movement to engage and disengage my clutch. I can now go in and out of gear smoothly but the rod is adjusted out to the max and the clutch stop bolt removed.

Would I run into any issues in the future with this?

Thanks and Latez,
-Dave

spiegel420 · 10-20-2014, 03:51 PM

I would use the stopper bolt. Otherwise their will be constant extra pressure on the master. Which may or may not encourage it to fail sooner. As long as youre happy with the pedal feel, and engament point, once that bolt is in, youre good! My car uses the cruise control release switch as the stopper.

09-19-2014, 06:27 AM	#1
ProjectPanda13 Zilvia Addict Join Date: Dec 2007 Location: Atlanta, GA Age: 36 Posts: 636 Trader Rating: (9) Feedback Score: 9 reviews	'pump up' clutch pedal issue I have been having an issue with 'pump up', very much like what DSM encounter with their clutches. Before driving, the clutch pedal is soft and engages low, but as I drive the pedal becomes stiffer and the engagement point moves higher up. When I adjust the pedal lower, like what the DSM guys do, I can feel the pressure release. But if I adjust it too low, I am not able to get into gear. All this happened about a year ago when I did a clutch replacement. I installed a ClutchMasters FX350 along with a their lightweight steel flywheel. I also installed new pilot and throwout bearing, not to mention arp flywheel bolts. After the install, I had to adjust the clutch pedal further out since I couldn't get into gear. The next morning, I drove the car to work and I first encountered the stiff pedal. I played with the adjustment for a week before finding a decent length that didn't allow the pedal to get too stiff, but still stiffer, and drove it til now. I also have to pop the clutch pedal sometimes to be able to get into gear. I also installed a Nismo slave cylinder to see if it helps, but it didn't Last night, after a long drive in traffic, my pedal lost all pressure and I had to pump the pedal multiple times to get pressure and also adjusted the pedal to the end of the rod. I made it home but with difficulty. I rebleed the system and have been able to drive it, but have to pop the clutch pedal more often now. Any idea what it could be? I am going to attempt to replace the master cylinder to see if that will solve the problem. Anyone experience this on their car? Sorry for the long explanation. Thanks, -Dave

09-22-2014, 04:59 AM	#2
Rayne Zilvia Addict Join Date: Feb 2005 Location: Earth Posts: 676 Trader Rating: (0) Rides Gallery: Rayne Feedback Score: 0 reviews	Is the clutch line coming off of the clutch master cylinder connected to the: A) dampner box or b) directly to the clutch slave cylinder? __________________ Do need the Factory Service Manual? Click here.

09-28-2014, 10:12 AM	#5
*FaLKoN240* Super Moderator Join Date: Jun 2004 Location: SoCal Temecula Posts: 16,885 Trader Rating: (73) Feedback Score: 73 reviews	I would've thrown the dampener box away when I changed the slave. In fact, that's what I did when I changed my slave cyl out earlier this year. __________________ Best way to do business with me? Make your best offer FIRST.

09-22-2014, 10:44 AM	#3
ProjectPanda13 Zilvia Addict Join Date: Dec 2007 Location: Atlanta, GA Age: 36 Posts: 636 Trader Rating: (9) Feedback Score: 9 reviews	The line goes through the damper box. I am hoping to remove it this weekend and see. -Dave

09-28-2014, 08:11 AM	#4
spiegel420 Join Date: Feb 2012 Location: washingotn Age: 37 Posts: 28 Trader Rating: (0) Feedback Score: 0 reviews	Air. That damper box is a pain to bleed. Remove it, bleed it, done.

09-28-2014, 01:06 PM	#6
ProjectPanda13 Zilvia Addict Join Date: Dec 2007 Location: Atlanta, GA Age: 36 Posts: 636 Trader Rating: (9) Feedback Score: 9 reviews	Yea, I should have at the time. But I had this pump up problem when I first installed my clutch without opening up the system, so I didn't think air was an issue. I haven't had time to do my clutch master cylinder replacement this weekend liked I had hoped. So hopefully, I can free up some time this coming week. I'll, definitely remove the damper box also. I'll keep every posted. Thanks. Latez, -Dave

10-20-2014, 08:54 AM	#7
ProjectPanda13 Zilvia Addict Join Date: Dec 2007 Location: Atlanta, GA Age: 36 Posts: 636 Trader Rating: (9) Feedback Score: 9 reviews	UPDATE: So I replaced my clutch master cylinder and removed the damper box. This has solved my clutch pump up issue. However, with the clutch master I had to adjust the rod all the way out to the end to get enough movement to engage and disengage my clutch. I can now go in and out of gear smoothly but the rod is adjusted out to the max and the clutch stop bolt removed. Would I run into any issues in the future with this? Thanks and Latez, -Dave

10-20-2014, 03:51 PM	#8
spiegel420 Join Date: Feb 2012 Location: washingotn Age: 37 Posts: 28 Trader Rating: (0) Feedback Score: 0 reviews	I would use the stopper bolt. Otherwise their will be constant extra pressure on the master. Which may or may not encourage it to fail sooner. As long as youre happy with the pedal feel, and engament point, once that bolt is in, youre good! My car uses the cruise control release switch as the stopper.