Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > Sport Touring: ST4 / ST3 / ST2 > Bleeding clutch

[Derek]

The slave will be full of air too. With it off the bike, open the nipple, push the piston in as far as it will go, tighten the nipple and release the piston. Do this 2 or 3 times and hopefully you will get there. Once the piston starts to move I found it useful to release the nipple with the lever held in. The clutch pushes the piston back and purges the air out of it. Tighten the nipple before releasing the lever or it will draw air back into the line.

[ColinF]

I kept this letter to the ed of Classic Bike when I found it some time ago because I've had the same probs you've had and this guy seemed to have it sussed
".....my experience after 30 years in the old bike business?Bleeding brakes the simple quick and cheap way.
Required: cheap plastic or glass syringe,preferably greater than 100cc.The bigger it is the fewer times you have to empty it.

Although it was not mentioned in the article,the design of the bleed nipple with the bleed holes in the side above the bottom taper means that a certain amount of air will be sucked down the bleed nipple threads when using any vacuum bleed sytem.I always remove the nipple first and wind a couple of turns of plumbers tape around the threads, just enough to seal.Be careful not to cover the small bleed holes above the bottom taper.

Screw the nipple into the caliper until it bottoms and back off around one turn.

Use syringe to suck fluid through system, maintaining fluid level in master reservoir.
Continue until fluid is no longer aerated.Lightly tapping lines, master, calipers etc as you draw fluid throught the system ensures a quick, highly effective bleed time and time again.

Tighten bleed nipple.Thread seal tape can be left in situ.It is actually best to leave it there as it seals the threads, minimizing water entry and the dreaded expensive 'broken nipple' syndrome!

To rebleed the system merely loosen nipple again and use the syringe.

A couple of pounds for a syringe is a much more economical proposition than a vacuum pump.

Occasionally customers have brought in bikes with brake systems that have defied their every efforts to bleed by the usual pump and release method. I love the looks on their faces when they see the job done to perfection in five minutes at the most.I refuse to charge them and give them a syringe to take home."

I haven't needed to try it yet but it reads well eh?
Goodluck

[mara]

Thanks for all the suggestions, I sorted it last weekend, the trick was to prime the slave cylinder. Doing this moved air much quicker and soon made the lever pumping method more productive. I haven't tried the syringe method, but it sounds good.

Tips for novices like me:
1) Prime the master and slave cyliner following instructions above (I found the easiest way to compress the slave piston, was to have it loose on the bike and pushed the whole slave unit onto the bike to compress the piston).

2) It really helped to have the drain tube I attached to the nipple and bottle to catch the fluid above the bleed nipple, this means the air floats up the tube, reducing the risk of drawing back into the system.

3) Keep an eye on the master cylinder and make sure the reservoir doesn't empty, otherwise you'll draw air back into the system - this is very easily done.

3) Be patient, it takes much longer than you'll expect (maybe the syringe method is the way ahead).

I'm back on the road.