Bleeding rear underslung brake

[greenmonster]

Pretty hard to do, especially if you've emptied the system, avoid it if you don't have to.
I emptied system, then tried all usual ways, pumping-bleeding, fast pumping,
filling from caliper. No cigar, very frustrating.

Tried the 2 pictured instructions page 1 in the http://www.apriliaforum.com/forums/showthread.php?t=15500. thread,
post 7 & 8:

https://www.apriliaforum.com/forums/attachment.php?attachmentid=32010&stc=1&d=1124045539

https://www.apriliaforum.com/forums/attachment.php?attachmentid=32011&stc=1&d=1124045657

Caliper bleeding, once w bleeder highest and once w fluid inlet highest, is ESSENTIAL. Period.

I did a lil bit more:
Loosend the rear screw of low chain slider and removed speedo cable.
so l could pry out fluid cable and hang caliper a little higher than fluid reservoir.
Bleed in both positions, bubbles out of both.
Left overnight w bleeder highest, no lid master reservoir. Was firmer next day.
Bleed both positions, all good.

Did this on my Multi, should be the same w similar systems.
Timeconsuming but do work.

[convict]

the only bleed i have ever managed on the rear on my s2r800 worth a damn is to remove the calliper and invert it.
 

[koko64]

Let's see, here's the methods I use, sometimes some, sometimes all.
1. Traditional lever/pedal pumping and bleed nipple drain hose (often with one way valve in the hose)
2. Moving the caliper to high point (pita on sss models)
3. Vacuum bleed pump (pulls it through)
4. Sonic method (vibrating instrument taped to line can jiggle out bubbles trapped in nooks and crannies)
5. Syringe reverse filling
6. Pedal held down overnight with block of wood or lever zip tied to bar
7. Bleed at the master cylinder nipple (if it has one) or its banjo bolt.

The rear brake line is too close to the exhaust on some models and Dot 5.1 might be needed. I've held off at present because changing fluid every 2-3 years is enough for me.

Strangely, keeping the rear brake pedal on with a small block of wood against the clutch cover case has worked well.

The secret is to persist with all the methods. It is a pita for sure as I get the job done on my old non abs monster in no time.