Bleeding clutch system

DanEC · #1 (**permalink**) 10-13-2012, 06:31 PM

Nose is jacked up in the air. Hose on the bleeder nipple buried in a jar of brake fluid. Couple loose connections at the start but after tightening them up the system was tight. Most of my cars have had manual clutch linkages - but guys, I've been bleeding brake systems for at least 25 years. I agree - something is wrong.

Are you vacuum bleeding or pressure bleeding from the slave bleeder? Are you leaving the pushrod to the clutch fork in?

patrickt · #2 (**permalink**) 10-13-2012, 06:36 PM

Quote:

Originally Posted by DanEC

Are you vacuum bleeding or pressure bleeding from the slave bleeder? Are you leaving the pushrod to the clutch fork in?

Yes, don't touch the rod to the fork. Put the surgical tubing on the slave bleeder, put the other end in a jar, crack the bleeder a bit, pump the pedal from inside the car, and the jar should fill up obviously and quickly - the tube will fill as well. If it doesn't do this, there's something wrong.

DanEC · #3 (**permalink**) 10-13-2012, 06:46 PM

Except for the pressure and vacuum bleeding experiment I've mostly tried to bleed it according to the manual - "Work the arm on the clutch pedal shaft (instead of pushing on the clutch pedal itself". Think I'll go back to stroking the pedal.

patrickt · #4 (**permalink**) 10-13-2012, 06:53 PM

Quote:

Originally Posted by DanEC

Think I'll go back to stroking the pedal.

That's what I do. When you have a nice stream coming out of the tube, filling the jar, and no tiny air bubbles anywhere, then you just adjust the fork nut, as per the manual, and you're done. Now, once in a blue moon you can get an air pocket in the slave cylinder and you can burp it out by pushing the slave's plunger back in manually with your fingers a couple of times. What will tip you off that that's occurring is if you've apparently bled the system well, but you don't get a lot of plunger travel against the fork when you push the pedal after you've closed off the bleeder.

Gaz64 · #5 (**permalink**) 10-13-2012, 10:35 PM

Seen this many times with hydraulic clutch systems.

Is the bleed nipple on the slave at the highest point on the cylinder?

Jaydee · #6 (**permalink**) 10-14-2012, 02:31 AM

Is the piston in the master cylinder bottoming out on the circlip. If not, then the port to the reservoir will be blocked by the cup. Occasionally, if the cup has swelled for any reason, it will also block the port.
JD

Gaz64 · #7 (**permalink**) 10-14-2012, 03:12 AM

Quote:

Originally Posted by Jaydee

Is the piston in the master cylinder bottoming out on the circlip. If not, then the port to the reservoir will be blocked by the cup. Occasionally, if the cup has swelled for any reason, it will also block the port.
JD

A very good point.

If the slave won't gravity bleed, this could be the reason.

DanEC · #8 (**permalink**) 10-14-2012, 05:26 AM

Quote:

Originally Posted by Jaydee

Is the piston in the master cylinder bottoming out on the circlip. If not, then the port to the reservoir will be blocked by the cup. Occasionally, if the cup has swelled for any reason, it will also block the port.
JD

I am getting fluid through the system so I tend to think I don't have this problem. Thinking back I think the cylinder of the slave was rotated where the bleeder was not on top - I'll see when I get back to it today. Also I think trying to bleed it by stroking the slave from the shaft arm instead of the pedal is working against me.

DanEC · #9 (**permalink**) 10-14-2012, 05:22 AM

Quote:

Originally Posted by Gaz64

Seen this many times with hydraulic clutch systems.

Is the bleed nipple on the slave at the highest point on the cylinder?

Good thought - it rotates but the braided line kind of fixes it in one position typically - I'll double check today. Don't have this issue with brake calipers (or mechanical clutch linkage). May need to loosen the braided hose and readjust.