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Discussion Starter · #1 ·
Hi!
After renovating a front brake caliper i notised that the pistons that go into the rubber bushings created a pushback (i belive it´s air inside) when i puched it together. Is it suposed to open again or should it stay closed?

Best regards
/Magnum
 

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Discussion Starter · #4 ·
The problem is that only the right side caliper does not release after braking. I have replaced the caliper but still have the same problem so i think it´s the proportional control valve.
 

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The problem is that only the right side caliper does not release after braking. I have replaced the caliper but still have the same problem so i think it´s the proportional control valve.
If it's only the right side caliper sticking, then it can't be the PCV. If the PCV was the problem, then the rear caliper would be sticking. If there was something wrong in the SMC, then only the rear would be sticking. If all the calipers were sticking, then it would be the brake pedal MC. It could the the delay valve but they rarely seem to cause any issues/ You could check that by making the right caliper stick, then release the pressure by cracking a line on the centre piston. I think :)
 

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:unsure:......hmmmm, it sounds like it still needs to be bled properly.

There could be an air bubble resisting removal, so maybe a vacuum bleeder will shift it, or perhaps rotating that caliper as you bleed might help shift it. (maybe your system needs new master and caliper kits ?......).

The bleeding procedure is detailed in the workshop manual, (manual and vacuum bleed).But two people are best for manual bleeding, including priming the DCBS if you have the FI model.
 

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:unsure:......hmmmm, it sounds like it still needs to be bled properly.

There could be an air bubble resisting removal, so maybe a vacuum bleeder will shift it, or perhaps rotating that caliper as you bleed might help shift it. (maybe your system needs new master and caliper kits ?......).

The bleeding procedure is detailed in the workshop manual, (manual and vacuum bleed).But two people are best for manual bleeding, including priming the DCBS if you have the FI model.
How does air in the system prevent the piston from releasing/retracting?
 

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G'day AusBB,

I've been out riding, so sorry for the delay responding. An air bubble in the system is like a balloon. As it heats up the air expands, so it will lock the pistons on the rotors and make the lever feel rock hard. When it cools down it shrinks and the lever then feels spongey instead of firm but with the normal play it should have.

Some bikes like my bloody Ducati, have Brembo calipers and these have a reputation for being :poop:'s to bleed as they can trap air inside.

I think this BB has some damage to it's pistons which just may be causing them to stick, but due to the age of our BB's, it could also be that it needs a full caliper refurbish, especially if the fluids have been neglected over many years. Gunk builds up, moisture contamination is also absorbed by brake fluid and corrodes the alloy parts and seals can go hard with age....... but if it's just an air bubble.... ;) easy.
 
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