My 2000 748s had soft rear brakes. I tried bleeding them, but had no luck getting a better pedal. I ended up replacing the master cylinder, brake line and caliper - basically the whole system - with new Ducati parts. I "bench bled" the master cylinder, installed the rear caliper and the new line. Now, despite getting fluid through the system with my power bleed pump, I can't get any pedal at all. I also tried removing the rear caliper from the mount and raising it up above the reservoir, but this didn't do it either. I get fluid bleeding through with the mitivac, but I cannot get any braking action. I've bled dozens of brakes on various bikes before and never encountered this issue. Everything has been replaced, so it should work fine. What am I missing? Thanks!
748 rear brake bleed question
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Here we go dude... the way the caliper is mounted is strange. What needs to be done is rather simple.
Just unbolt the caliper and slide it along the rotor until its gently resting at or near the 12 o'clock position...anywhere that the bleeder valve is pointing up. The way that its mounted on the bike makes it very to bleed-since the air bubble will rise to the uppermost part of the caliper, it will not bleed correctly as it rests upon the bike naturally.
Good luck and let us know how it goes.
I know exactly what you're going through-I also had to figure this out for myself.
P.S.-If you don't need your leftover parts, let me know
Just unbolt the caliper and slide it along the rotor until its gently resting at or near the 12 o'clock position...anywhere that the bleeder valve is pointing up. The way that its mounted on the bike makes it very to bleed-since the air bubble will rise to the uppermost part of the caliper, it will not bleed correctly as it rests upon the bike naturally.
Good luck and let us know how it goes.
I know exactly what you're going through-I also had to figure this out for myself.
P.S.-If you don't need your leftover parts, let me know
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205 Posts
The 12 oclock thing really works - just did mine yesterday. BTW, anyone know why these things need to be bled every few months? Is just scoring the in the MC bore due to dirt getting in there or is there a design flaw?
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Hmm...don't have to bleed mine every few months.
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Nor do I. i would check to make sure your lock nut on the foot pedal push rod isn't loose and allowing the shaft to spin in or out, in turn, shortening or extending the throw...making it feel as though your foot pedal has either gained feel (in my case, too much causing a lock up) or lost feel causing a gummy sensation associated to an air bubble. Take a look and let us know. Good luck!
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Bleeding Rear Caliper
I agree with Nacademus about re-mounting caliper so bleed valve is at the top. I actually extend this principle to bleed system effectively, particularly when replacing hose. OK - first ensure pedal actuation is working (might be a good time to lube pedal) and adjust freeplay on pushrod to minimal, but still with clearance! Remove brake hose cover on chainguard and any other components necessary to allow you to place caliper up on rear subframe. This means the brake hose will be running UPHILL all the way to the caliper. I then place a clean piece of flat material the same thickness as the disc between the pads, and secure this to the bike eg. with a G-clamp. Ensure bleed valve is at the top, bleed until air stops coming through hose, and re-mount caliper. This works for clutch etc. and saves time and fluid! (With clutch slave cyl. a short pushrod eg. from old bevel motor and a 'backing plate' to prevent piston moving is required). Good luck! Pat
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