[Rupes]

Guys,

I have a question after reading several DIY's on removing the CDV. How do I bleed the line. Please be very specific. Do I loosen the nut then go inside the car and pump the clutch a few times, then go back to the nut and tighten it again? How do I know when I've cleared the line? If I loose some fluid from the CDV do I add more fluid to the brake fluid reservoir? Which kind should I buy? I've never even changed my oil before so I'm quite nervous.

[Efthreeoh]

You bleed the line the same as would bleed the brakes. You need to follow one of three methods:

Use a pressure bleeder that pressurizes the brake fluid reservoir and then open and close the bleed valve on the slave cylinder. Attach a clear tube on the bleed valve and put the other end in a jar with a bit of fluid in it so as to not let air back in the system

Or, use another person to pump the clutch pedal while you open and close the bleeder valve. The valve should be opened while the other person slowly presses the clutch pedal, which will bleed the air out of the line and then close the valve while the clutch pedal is still in the down stroke. Use the same clear tube setup as above. Make sure the person pumping the pedal does not bottom-out the clutch pedal.

Or get a vacuum canister (oil extractor) and attach it to the bleed valve to pull the hydraulic fluid through the slave cylinder.

Any of these procedures takes very little fluid to move through the system the get the air bled out.

[Rupes]

Originally Posted by Efthreeoh

Or, use another person to pump the clutch pedal while you open and close the bleeder valve. The valve should be opened while the other person slowly presses the clutch pedal, which will bleed the air out of the line and then close the valve while the clutch pedal is still in the down stroke. Use the same clear tube setup as above. Make sure the person pumping the pedal does not bottom-out the clutch pedal.

Thanks! So I stop the open / close method once fluid (and not air) comes out when the clutch is depressed?

[Efthreeoh]

Originally Posted by Rupes

Thanks! So I stop the open / close method once fluid (and not air) comes out when the clutch is depressed?

I'll try to explain the system to you so you can understand what happens. The hydraulic clutch system works in the same way the brake system does. The there is a "master" cylinder attached to a "slave" cylinder via a hydraulic line. There is a piston in each cylinder. When to press in the clutch pedal it forces an equal amount of pressure on the piston in the slave cylinder, which then disengages the clutch.

When you open the system to the atmosphere, like when you disconnect the line to remove the CDV, the vacuum in the system is broken and air is allowed into the line since air always fills a void (vacuum). The best way to minimize the amount of air introduced into the system is to clamp the hydraulic line at the very end with a hydraulic line clamp. Once you reattach the clutch line, you then apply pressure to the system by either applying pressure to the hydraulic oil in the brake fluid reservoir (it feeds the clutch master cylinder), or you pump the clutch pedal, or you pull a vacuum on the line.

Once the air goes out of the line you close it. Use clear tubing to see the air bubble move out of the bleed nipple, then close the bleeder valve.

[Rupes]

Originally Posted by Efthreeoh

I'll try to explain the system to you so you can understand what happens. The hydraulic clutch system works in the same way the brake system does. The there is a "master" cylinder attached to a "slave" cylinder via a hydraulic line. There is a piston in each cylinder. When to press in the clutch pedal it forces an equal amount of pressure on the piston in the slave cylinder, which then disengages the clutch.

When you open the system to the atmosphere, like when you disconnect the line to remove the CDV, the vacuum in the system is broken and air is allowed into the line since air always fills a void (vacuum). The best way to minimize the amount of air introduced into the system is to clamp the hydraulic line at the very end with a hydraulic line clamp. Once you reattach the clutch line, you then apply pressure to the system by either applying pressure to the hydraulic oil in the brake fluid reservoir (it feeds the clutch master cylinder), or you pump the clutch pedal, or you pull a vacuum on the line.

Once the air goes out of the line you close it. Use clear tubing to see the air bubble move out of the bleed nipple, then close the bleeder valve.

Ok, I'll give it a shot. If for some reason I don't do this correctly, and a tiny bit of air remains, will that eventually find it's way out or will it lead to some kind of catastrophic event?

[Efthreeoh]

Originally Posted by Rupes

Ok, I'll give it a shot. If for some reason I don't do this correctly, and a tiny bit of air remains, will that eventually find it's way out or will it lead to some kind of catastrophic event?

No catastrophic event. But you may notice a spongy, non-direct feeling pedal for a bit. When I took my valve out, I did not bleed the system, I never noticed an issue.

[Zero_09]

Originally Posted by Efthreeoh

You bleed the line the same as would bleed the brakes.

I also have some questions about this procedure. I bought a Motive brake bleeder kit to do my brakes. From what I read you supposed to bleed the brakes by opening the bleeder valve at each caliper. Where is this same brake bleeder valve that you're talking about?