Bleedin Hell

[Paranoid Dave]

Right, I'm a novice with a spanner and it's time to do that horrid job of bleeding brakes and clutch, or should I say now that I've tried and failed it's time for some help on how to bleed.

I've replaced the cables so it's not as if I'm just pushing new fluid through, I have no pressure at all to start with and can't figure how to push the fluid through. I've played and tried all I can :banghead:

Please help?

[Pomp1]

I've always found that on Ducati, for some reason, reverse bleeding is the best option.

[simons]

Had similar when changed fluid reservoirs on jimmy's s4. Airlock in master cylinder, it was just a case of modulating the pumping speed between fast and effing fast until the master 'caught'. Failing that, get yourself a big syringe off ebay and reverse bleed. Word of advice, put some ptfe tape on bleed nipple threads. i found that air gets sucked back through them while bleeding.

[Paranoid Dave]

what do you mean by reverse bleed. I have a large syringe and yes i did try pulling air out or pushing fluid in but as you said it leaked through the nipple threads.

[Shandy]

If i remember the front brake on mine was a nightmare due to airlocks in the mater cylinder, someone recomended to me tapping the master cylinder while pumping the lever. This helped no end you could see the air bubbles come back up in the resviour, still took a couple of days of leaving it over night though to chase it all out!!

[simons]

Reverse bleeding means that fluid is pumped in through the bleed nipple in the brake caliper and upwards to the master cylinder. You can use a big syringe connected to the caliper via plastic tube, you must be careful that fluid does not squirt out through the fluid reservoir and all over the paintwork - it will strip paint!!

[gary tompkins]

I think you also need to keep lever pulled into the bar with a cable tie. Otherwise the fluid can't get through to resevoir. I always try to prefill (prime) calipers and new lines, as it does help to get things started.

For regular manual bleeding - you need to open nipple, pump lever, hold lever at the end of stroke, lock nipple and release lever. Also make ensure end of bleed tube stays submerged in catch bottle, and reservoir is topped up as fluid is expelled.

[Paranoid Dave]

Right, next time i get in the garage I'll put all that into action, the tape around the thread sounds good as it could solve the leaky thread when unlock the nipple.
There's no bodywork so no paint to get sprayed, must remember to pull the lever in though when pumping uphill.

Thanks all, no doubt i'll be back...

[He11cat]

Good Luck Dave... :)

[Capo]

I think you also need to keep lever pulled into the bar with a cable tie. Otherwise the fluid can't get through to resevoir. I always try to prefill (prime) calipers and new lines, as it does help to get things started.
.

Actually, the hydraulic circuit is open to the reservoir with the lever in the released position. the action of squeezing the lever closes of the port to the reservoir and the brake action comences. (compesnation port action omited for simplicity)

When reverse bleeding it is important to ensure the hose connecting the nipple and the fluid is free of air as it will be drawn into the system.