April 14, 201412 yr The calliper in the video does not seem to behave like monoblock / 1 piece construction, it looks like flex in a bolted together calliper, can you provide some video / photos of it from other angles. Your symptoms suggest one or more of following Air in fluid Dirt / corrosion in seal groove Corrosion / roughness on pistons Shaving of calliper bore between piston and bore - shaving / scraping off bore due to pushing piston in at slight angle Unidirectional seal fitted wrong way round. Edited April 14, 201412 yr by dadof2
April 14, 201412 yr This is what it looks like (sorry, no video now). The more I think of it, the more sure I am that something is wrong with the pistons....
April 15, 201412 yr You should still be able to pry or push the pads back to insure the pucks are moving. If not dragging on the rotor they are likely not stuck. I can only tell you that every time I have had to use the water method I thought "much better but not there yet", then either put the bike away for the day or resumed riding then later all seemed good! Galfer pads do not like to work well in water anyway is seems! All mine have been AJP, so cannot tell more. I know they had some issues on the master cyl's and mods to fix them, but the calipers I have not heard much. The AJP do flex a bit when pulling super hard! Much harder than what I think normal.
April 15, 201412 yr Can you undo the access caps on these callipers -need something like a large spline / torx drive tool Get the pistons and seals out then check the pistons move freely in the bores without the seals. Examine the seal grooves very carefully using a dentists magnifying mirror.
May 7, 201412 yr As I was doing some other work on the rear end I replaced the caliper seals and cleaned the master cylinder. The rear brake got much better, I'm actually able to lock the rear wheel now and making manouvers on rear wheel feels much more secure. One thing I noticed was that the rubber insert of the rear reservoar helps to push oil into the master cylinder if you create a bit of overpreassue when inserting the rubber. The problem seems to be that when I release the pedal, oil will get sucked from the caliper instead of the reservoir. This causes the pedal to not actuate early enough... Front is "good enough" but I will replace the seals in the front caliper as well.. when time allows.
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