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Clutch doesn't have any pressure

Stevey629

Stevey629

Contributing Member
Joined
25 October 2009
Messages
123
Location
San Diego, CA
Driving home today, I pushed the clutch to downshift, and all of the sudden, I just felt NO pressure on it. Terrifying feeling on the freeway, considering I was miles from my destination. The pedal didn't snap to the floor though, it sprung right back up just fine. It just didn't seem to engage the actual clutch. If I pressed it all the way to the floor, I got a tiny bit of grab, just enough to get it into gear while match revving. The second I let up from the floor, the clutch grabbed right away. From this point, the rest of the pedal travel is as I said before. It just has no positive pressure on my foot, but comes all the way back up to its resting position. It definitely got worse and worse as I neared my house, and thankfully I made it home. No gear grinding, and once in gear, the gas input was linear and completely normal based on rpm to mph, so I am assuming that the clutch isn't bad.

I inspected the footwell, and there are no drips or leaks. Checked the master cylinder reservoir, and low and behold, it was a dry well. The little float is was rattling around. I looked under the car by the gear linkage casing, and its definitely leaky.

So, to beat a dead horse, am I to assume that replacing the master and slave cylinder will cure my problem? Are there other things that I should fix while I'm at it? I've read quite a few really good posts already about how to replace them, but I am just wondering if my particular clutch symptoms might be something else in addition to/in lieu of leaky cylinders. NSXclear, thanks for your help. "clutch" in a time of crisis. :)
 
The NSX clutch hydraulic system is fairly straightforward, so it probably will fix the problem to replace both cylinders. My only thought is that you might have a leak on one of the clutch lines between the master and slave - it's a long way between the two and that missing fluid had to go somewhere. Therefore, check for a leak along the lines too.

Edit - I also replaced the rubber hose line that goes from the damper to the slave when I did mine.
 
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The clutch master is a pita to do because access is very tight at under the dash with that large intrusion from the side rails.
 
Stevey629 said:
I found an image on one of the threads here. I looked under my car, and that is what is soaked. The two lines coming out are also wet, or look to be anyway.

http://www.nsxprime.com/forums/attachment.php?attachmentid=1856&d=1058742976


^ original thread: http://www.nsxprime.com/forums/showthread.php?s=&threadid=20258
Click to expand...

Hmmm, well that pic is of the shift lever linkage on the transmission. Those two cables run back to the gearshift lever and do not interact in any way with the clutch hydraulics. Maybe your slave blew out and dripped onto it?
 
Check the Hydraulic pipe hasnt split. It runs from the slave cylinder to clutch damper line. Its easy replaced from above. Remove your airbox and you will see it.
 
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I'll check the line when I get home from the office today. Do you have a pic of the line? Can I see it without removing the coolant bottle?

EDIT: nvrmind. U just said remove airbox. Well, I have a K&N cone, so perhaps I should be able to see it after all?
 
Yeah you should be able to see it ok, I have a cone on my car and can see it no problem. I should have a pic so will post up shortly.


Stevey629 said:
I'll check the line when I get home from the office today. Do you have a pic of the line? Can I see it without removing the coolant bottle?

EDIT: nvrmind. U just said remove airbox. Well, I have a K&N cone, so perhaps I should be able to see it after all?
Click to expand...
 
Here you go

[VIEW FROM UNDERNEATH]

The silver cylinder on mine is the NSX-R damper joint, yours will look similar but more of a bronze color, beside that to the right is the clutch hydraulic line, [BLACK RUBBER HOSE]

SAM_0859-1.jpg
 
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Thank you so much for that pic. I will let you know once I have a chance to get home to check it out. Do the hoses typically fail at the joints? Pinhole leaks? Or do they have a tendency to just rupture/split?
 
The ones I worked on had splits on the hose itself, some were really bad some with just a pin hole.

Stevey629 said:
Thank you so much for that pic. I will let you know once I have a chance to get home to check it out. Do the hoses typically fail at the joints? Pinhole leaks? Or do they have a tendency to just rupture/split?
Click to expand...
 
Sudesh said:
Well if its leaking replace lol:smile:

Usually if I do a master cylinder and slave cylinder replacement, I replace that hose also along with a new O ring.
Click to expand...


This is what I was talking about in my earlier post. Also, my replacement hose came with an o-ring pre-installed on it.
 
First off, I'd like to personally thank VSYCLEAR. He came to the rescue and helped me out today with replacing the slave cylinder and clutch hose. I am pleased to report that pedal pressure has returned! And its smoother than ever. Fluid also needed to be changed regardless, (gunky and black) so this was a major improvement in clutch response and feel. I still need to replace my actual clutch at some point, but at least I know that for now, the hydraulic pressure is good.

After removal of the line and the slave, we found out that it was most likely just the hose. It was leaking right where the crimp joint is on the rubber line to the metal casing, on the slave cylinder side of the hose (not the hardline side). The slave looked very corroded around the boot joint though, and would have probably failed sooner or later, so replacing it was a good idea. The master looked like it had been replaced recently, so I didn't think it needed to be replaced.

Anyhow, just wanted to report my results in my thread. Thanks again VSY!
 
No problem. I'm just glad it all worked out and we were able to get it up and running.

My previous username was vsy05, but my new user name is NSXclear. That probably confused you.
 

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