I would remove the caliper and then the brake pad pin and check your brake pad thickness as well as the condition of the single pad pin for corrosion. Then I would separate the caliper and check there is enough of the correct grease on the sliding pins and that they too are not corroded.

Pump out the piston a few millimeters, (if it's not already out too far) and check for corrosion. If this is corroded it has difficulty withdrawing back in to the calliper when the brake is released.

Be care full with the rubbers as they are prone to expanding if they have been exposed to the incorrect 'cleaning' fluids / sprays.

A sure sign those sliding pins are sticking will be that one of the two brake pads is thinner than the other.

Also check your rear disc for scoring on both sides as this may occur if a pads has worn away too much.

When correctly fitted back on the bike you should be able to feel, by hand, a very small amount of 'float' in the calliper.

Forgot to mention......refilling with too much brake fluid after a change, or bleed, will cause the pads to deploy and then get hot, expanding the brake fluid and further deploying braking force.

When it's back together, don't forget to pump your brake pedal to bring the pads back to the disc.

These Brembos are used on many motorcycles and the cheaper parts supplier for rubbers is BMW. Yamaha charge twice as much for the same part.

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