[clenart50]

I'm looking for some pointers on clutch bleeding. My usual approach is typical: tube on bleeder valve, squeeze lever, open and close bleeder, repeat until bubble-free. It works well enough but I'm wondering if anyone has any general tips and also, specifically, how does one bleed the reverse direction?

Using my MityVac on push (as opposed to pull) with a fluid-filled tube to the bleeder valve, can I push fluid (and bubbles) up to the reservoir? Do I need to loosen the nut I see in the reservoir ('04 999)? Worry about a geyser?

Is there any advantage to this approach?

Thanks,
C

 

[tye1138]

I usually suck through a bunch of fluid with my fluid evacuator. Then I bleed the clutch master, then slave using the pump 3 times, hold lever, open valve and close method. Works every time and you're pretty guaranteed to get it right almost every time.

 

[clenart50]

Thanks for the quick reply. What's the difference between bleeding the master and the slave? I bleed via the slave. Am I missing some basic maintenance step? I don't recall LT Snyder mentioning master bleeding.

 

[Largerthan9]

Remove the wheel and brake pads to avoid contamination of the rotors and the pads. Position the lever so that the highest point in the system is the inlet for the reservoir. That way you do not have to "burp " the lever afterwards. I always bleed from the bottom up to the reservoir because of physics. When you bleed from the top down bubbles will try to raise up against the downward flow of the fluid. pushing the fluid from the bottom the bubbles will naturally raise up with the fluid. It also helps to push the caliper pistons fully into the caliper to ensure that you got all of the old fluid and bubbles out of the whole system. I use a regular plunger type syringe. It is not complicated. I will bleed the system twice. once to get all the old fluid out. then I will close the system and compress/squeeze the lever with a strap or zip tie and let it sit for a while. While it sits tap on the system with the handle of a screwdriver to break loose any bubbles that are clinging to the inside of the calipers and the lines. This compression pressurizes the fluid and causes any trapped air molecules to form bubbles that will come out on the second bleed. It also helps to push the caliper pistons fully into the caliper to ensure that you got all of the old fluid and bubbles out of the whole system. Once you open a bottle of brake fluid throw out the leftovers. The fluid is hydrophylic meaning it attracts moisture from the air. Water is very bad for brake systems.

 

[DMCTRUBY]

There was a lengthy thread on bleeding about a month or so ago. I noticed in your "process" above you did not mention burping the clutch master. Even the best slave end bleed will leave some tiny amout of air, which will rise to the highest point. So as a last step it is always a good idea to open that master bleed screw, pull the clutch lever in slow and hold it, then tighten back down the bleed screw and slowly let out the clucth lever. Make sure before you do that the clutch fluid is topped off to the proper level first.

 

[Largerthan9]

Fixed it. I do not "Burp the lever".

 

[clenart50]

When describing bleeding the master, do you mean loosening #14 in the pic above? Do you then squeeze the lever again or do you push fluid up from the slave?

 

[clenart50]

Oh--one more question that was never clear to me:

how does the position of the lever influence the efficacy of the bleed and the feel of the lever once done? I have pazzo levers--if I bleed it when it's dialed to 6 (longest pull distance), does that mean I should ride at 6? If I want a 3, should I bleed at 3? Or bleed at 6 and then dial down when done?

 

[st2lemans]

Fixed it. I do not "Burp the lever".

That's because you don't have a xx9. The design allows air to become trapped under the bleed screw inside the reservoir, and can only be removed by bleeding at the screw.

And yes, it's the screw that seems to be #14 (but isn't). It has two parts, and you loosen the inner part with a 6mm wrench (the outer part attaches the reservoir)

The lever position has nothing to do with bleeding. Bleed it at any setting you like, and use it at any setting. Probably easiest to bleed at the longest setting, though.

Tom

 

[clenart50]

... you loosen the inner part with a 6mm wrench...

Tom, thanks for the tip. Adding that step to bleeding was revelation. After routine slave bleeding, I loosened the 6mm in the reservoir, gave the lever a squeeze and tightened it. Wow. I haven't had that good a clutch feel for many miles.

C

 

[DMCTRUBY]

yep, that was what I was trying to tell you

Tom, thanks for the tip. Adding that step to bleeding was revelation. After routine slave bleeding, I loosened the 6mm in the reservoir, gave the lever a squeeze and tightened it. Wow. I haven't had that good a clutch feel for many miles.

C

 

[clenart50]

very cool! thanks for your help and thanks to everyone who chimed in. i just finished a quick ride and, wow, what a difference!