I have an 08 nismo and i replaced the clutch with an OS Giken twin disk clutch. The clutch line was never changed, the car has 4k miles on it. Everything is fine but the pressure inside of the hydraulic system seems to drop after driving for awhile (a few miles). We bled the system 3 times already, the first few minutes it feels perfect and then slowly drops and then the clutch pedal would get stuck about 3/4th of the way as if there is not enough pressure to push it back out. I've searched here and found that you have to bleed it for a long time till you get all the air bubbles out. We've done that. The way we bled it was push down a few times, hold it down, open the bleeding valve on the tranny, pump again, about 15 times total like this, and always made sure the reservoir is topped off with fluid. I don't know what else to do with it.

 

i had that problem in my o3 enth model. however i didn't have no working partner to help me. But me and my girl did it .. she ingaged the clutch petal and i while i turn the valve .. im pettle was perfected until driving it slowly drecreased back down while driving on the freeway.. my solution to this was as i come to a stop i would rapily pump the clutch to get the fluid to circulate.. however it does act up once in a while but im going to just change the master cylinder on the tranny... so problem would be solved.. so just make sure ur resivoir is full to max and that you do not have any leaks in ur system.. just purchase a new master cylinder install it and then see what it does from there.. i still havent gotten mines but it will get changed.. come to think of it my fluid was brown contaminated so, i had no choice but to drain it and replace new fuild in the resivoir... hope this works for you and wish you well..

 

There are quite a few detailed threads on how to properly bleed them.

You said you did it 15 times. 15 times doesn't constitute "a long time" like everyone says. It took me over an hour to bleed mine when i changed out the hydraulics. That's just an hour for the pumping and closing.

Also, it's not a pressure built system like brake systems. You have to open the valve slightly, THEN have someone push down on the pedal so it presses the fluid out of the cylinder. Then you close the valve before they lift up on the pedal. After a few times of that then stop and pump the pedal a number of times to see if you have good pressure. If not then keep doing it.

 

another question.

how do you know the pressure in your system drops? can you explain the symptoms you're having?

 

i did exactly what you said above. Thing is, when i pump the pedal and then keep it to the floor, we open the valve, then close it, then i release the pedal and it stays on the floor. I have to manually move it up and down until there is enough pressure to make it spring back up on its own.

The symptoms are I'm driving and the pedal feels stiff and the clutch feels great, no jerky shifts, smooth engagement every gear, and i can drive either slow or fast, with or without changing gears, the pedal gets softer and shifts become more jerky, every engagement is rough because of the pedal being soft and not having enough pressure to spring back up. and then a few minutes later it becomes stiff again, then goes soft again, on and on. But later it's worse and doesn't get better anymore like there is tons of air in the lines. It gets stuck half way and slowlowly comes back up, or gets stuck about an inch away from being back up and i have to pull it myself. It's irritating to say the least because i do not know what else to do. The master cylinder could not be the issue because the car has 4k miles on it and i never really pushed it hard. The stock clutch was perfect in terms of pedal feel so everything was 100% before the new clutch went in.

 

The pedal staying down is normal. It will continue to do that until all the air is out.

Like i was trying to say earlier these systems aren't a pressurized system like brakes. It's a ratio of input mastercylinder movement for slave cylinder output. They do'nt continiously build pressure when you pump them therefore you have to open the bleeder FIRST then push down the pedal so it squishes the fluid out. Putting it to the floor then opening the bleeder will remove SOME fluid, but not the amount that opening first then pressing down will. You'll be surprised on the amount of fluid that will come out when you do it like that. Then after a few rounds of that lock up the bleeder and pump the brake pedal up a few times. If it doesn't come up on it's own after a few pumps then there is more air to be removed.

This process takes a long time and for me I even had to do it a second time a week later just for extra measure.

Also, hydraulics can go out any time. Just because it was working before the clutch install doesn't mean it didn't crap out right after you installed the new clutch. It's a fluke and odd that it did it all of a sudden but that happens sometimes.

It sounds like the master or slave is dying by the amount you've bled it. I would keep trying before replacing them though. I went through a quart of brake fluid to get all the air out of mine.

 

Can I reuse the fluid that comes out of the tranny and recycle it or that fluid is no good once it went through the system? And also, the reason the system is not the same as before wiht the old clutch is because the tranny was taken out of the car completely and the lines disconnected, thus the air had got inside of it. I didn't know that you had to open first, then press down, that's a new one. Thanks for your help, i'll try it out asap and post the results here.

 

From the 06 Service Manual -

CLUTCH FLUID PFP:00017
Bleeding NCS00008
CAUTION:

Monitor fluid level in the reservoir tank to make sure it does not empty.

Do not spill clutch fluid onto painted surfaces. If it spills, wipe up immediately and wash the
affected area with water.
NOTE:
Do not use a vacuum assist or any other type of power bleeder on this system. Use of a vacuum assist or
power bleeder will not purge all the air from the system.
1. Fill the master cylinder reservoir tank with new clutch fluid.
2. Connect a transparent vinyl hose to the air bleeder.
3. Depress the clutch pedal quickly and fully a few times and hold
it.
4. With clutch pedal depressed, open air bleeder to release air.
5. Close air bleeder.
6. Release clutch pedal and wait for 5 seconds.
7. Repeat steps 3 to 6 until no bubbles can be observed in the
brake fluid.
8. Tighten air bleeder to the specified torque.


When I bled my clutch with this method, I had to lift the pedal back up after each bleed cycle. I was just bleeding it to get new fluid in - I didn't replace any parts or line.

 

dude, you have to keep at it.........thats the thing.......there is a peski azz airbubble up in dat hoe bag that isnt budging and your freak'n out..trust me i know from experience...

continue on and it will come out..

Since i drift and dont ever wanna deal with this crap again i did this:
https://my350z.com/forum/engine-driv...ht=power+bleed

with that mod, it takes longer to set up a tube and soda bottle at each wheel then it does to bleed the clutch line....

-J

 

I wouldn't reuse the fluid. The bottle you collect the fluid in could contain contaminates so it's not worth risking.

Just get a huge jug of DOT 4 at the parts store for a few bucks and go from there.

I know the service manual says to open the bleeder AFTER you depress the clutch but that's not the way most of the techs do it. I was shown the method i mentioned by a master BMW tech who works for Dreyer BMW and Infiniti. It bled perfectly for us this way and that's how he has done thousands of cars.

It's a serious pain in the butt.

 

fixed for accuracy!

-J lol..

 

you can never get all the air bubbles out by regular pumping style.
here watch this video the Best way to bleed Clutch system.
Start watching from 4min in. this method works for all cars and trucks.

http://www.youtube.com/watch?v=wdf--...eature=related

 

build a pressure bleeder you can make one for about $30 and you will wonder how you ever bled anything without it

 

that man in the video is a genius!

 

^ yup.

 

update

i bought a motive power bleeder the other day and bled my clutch again just like this guy does on the video. The problem is still there, and not immediately apparent, but only after a few miles of driving it goes soft again. Any help would be greatly appreciated. I'll try to bleed it tonight again by just pumping the pedal with the bleeder valve open and see if that does it.

 

took the car to the dealership and turns out it was my master cylinder that went out. They replaced it and now the problem is gone.

 

i was just about to say it was probably a hydraulic failure if bleeding it only worked for a short while.

 

Thanks for all the info guys, will be doing my clutch and line this spring and was wondering about the easiest way to do this

 

I just experienced this clutch bleeding ordeal on our '03 Touring. Could not get any new fluid to move through the system after repeated pumping and trying a vacuum bleeder.

Turns out the free play adjustment rod and pedal was stopping the clutch master cylinder piston from moving all the way to it's rear to open the fluid port to the reservoir.

Make sure you adjust that rod in so the piston moves all the way back, then it's just a simple pump and hold old school bleeding procedure.