Rear Caliper Issues

[mkirkby]

Hi All,

I had issues trying to get the pins out of my rear caplier (1200 Bandit) so gave up in the end and got a 2nd hand replacement caliper. Fitted everything fine and bled the system but I still can't get a good solid feel on the pedal.

When I clamp the hose just before the caplier, everything is solid on the pedal so the issue is obviously inside the caliper. If have bled the brakes using gravity bleeding and am sure the all the air has been removed as much as possible using this method. Questions are:-

Using normal bleeding is it possible for the to still be an air pocket in the caliper that is very difficult to extract?
Assuming all the air is removed, what else could be wrong with the caliper? There is no sign of any fluid escaping past the seals so could something internal be broken? I though calipers where pretty simple things and that there isn't much to go wrong.

Thanks
Mel

[BuzZz]

It sounds like there is still air trapped in the caliper. If you have no access to a system that will reverse-bleed the system, you could try removing the caliper from the mount and bleeding it with the caliper at a different angle (or several angles). Just stick something about the width of the rotor in there to keep the pads apart.

Don't clamp the brakeline. That's just asking for a blown hose sooner than expected.

[PeterTrocewicz]

I had the same problem with my Honda a few years ago. I tried all thetricks suggested above. After about 4 hours of fighting with it, I went out and bought a vacuum air bleeder for my air compressor. Done in less than 5 minutes. Works great for other things too: emptying the coolant bottle on my bike when I'm changing the coolant, changing the oil on equipment where you cannot get to the drain plug (such as the Argos), replacing the calipers on my car. I know, I cheated.

[BuzZz]

Agreed, a power bleeder of some sort is best. Mine will suck or pump, so reverse bleeding is possible. It is much more effective to push a trapped air bubble up than to suck it down. Although either is easier than the 'ol pump-n-bleed method.

[mkirkby]

Thanks for the pointers guys. I'll assume I've got more air trapped and try a multitude of positions to get it to release.

Cheers
Mel

[mkirkby]

OK, just to update, all sorted now.

I actually ended up reverse bleeding with tubing and a syringe, but it was thanks to your replies that made me realise there could still be air trapped and that the caliper was sound.

Thanks for the pointers
Mel

[BuzZz]