So I was bleeding my clutch after changing the angle of the master cylinder banjo bolt. After the third or so cycle of squeezing and bleeding, the lever lost all its resistance. Now when I squeeze it, it just goes flat against the bar and comes back. It is not pushing fluid. I made sure my reservoir was still full, then pulled the banjo bolt completely off the master cylinder. I expected the fluid to come gushing out but - nothing. I also tried putting vacuum on the slave bleed screw and it is just sucking bubbles from somewhere. I took the slave off - looked okay.
I don't know but it seems like something is wrong in the master and it is just pushing air around. I can't find any leaks or puddles of DOT 4 hiding anywhere. It was working fine up till now. Any ideas?
Use the vacuum pump as a pusher (mine does this) to pus fluid back into the ressy and see if some dirt got lodged in the line.
Just make sure you've got something over the ressy as if there is something lodged, when it comes loose you don't want that fluid spraying all over.
As I waited for the wisdom of the board, I decided to go jack with it some more. I took the banjo bolt off the master cylinder, stuck it down in my bottle of DOT 4, and sucked fluid into it. Then I took the clutch assy. off the bar and poured DOT 4 down into the hole where the banjo bolt was. Then I slammed it all together. Would you believe it worked? I still don't understand why it happened or why the fluid in the reservoir wouldn't come down when I tried to bleed the air out. Anyone? I verified that the fluid would move now by bleeding it once again. No problems at all this time. Sure enough the reservoir fluid level dropped as it should. I remember a thread where somebody (Ducpainter?) had posted a cutaway view of the master cylinder assy. Does anyone have a link to that?
Quote from: vaclav on August 08, 2009, 07:30:42 PM
As I waited for the wisdom of the board, I decided to go jack with it some more. I took the banjo bolt off the master cylinder, stuck it down in my bottle of DOT 4, and sucked fluid into it. Then I took the clutch assy. off the bar and poured DOT 4 down into the hole where the banjo bolt was. Then I slammed it all together. Would you believe it worked? I still don't understand why it happened or why the fluid in the reservoir wouldn't come down when I tried to bleed the air out. Anyone? I verified that the fluid would move now by bleeding it once again. No problems at all this time. Sure enough the reservoir fluid level dropped as it should. I remember a thread where somebody (Ducpainter?) had posted a cutaway view of the master cylinder assy. Does anyone have a link to that?
Wasn't I that posted the cutaway....
I think you got a bubble in the master somehow. I've had it happen by turning the bars with the fluid level low.
Sounds like you got it out.
I had to stick a bleeder bolt on the master banjo side to get air out of top. And snapped lever a bunch. Air seems to collect there- sometimes.