The fluid seal (piston seal) [A] is placed around the piston to maintain clearance between the pad and the disc. If the seal is in a poor condition, it could lead the pad to wear excessively or the brake to drag, which may cause the temperature of the discs or the brake fluid to increase.

Brake fluid leakage around the pad.
Brakes overheat.
Considerable difference in inner and outer pad wear.
Seal and piston are stuck together.
If the fluid seal is replaced, replace the dust seal [B] as well. Also, replace all seals every other time the pads are changed.
Front Caliper [C] Rear Caliper [D]

Caliper Installation
Rear Caliper Dust Boot and Friction Boot DamageThermostat Installation
Replace the O-rings [A] with new ones, and apply grease
to them.
Assemble:
O-rings
Thermostat Housing [B]
Thermostat [C]
Thermostat Cap [D]
Install the thermostat [A] in the housing so that the air
bleeder hole [B] is on top.
Tighten:
Torque - Thermostat Cap Bolts: 5.9 N ...
Intake Air Pressure Sensor #1 Removal
NOTICE
Never drop the intake air pressure sensor #1 especially
on a hard surface. Such a shock to the sensor
can damage it.
Remove:
Air Cleaner Housing (see Air Cleaner Housing Removal
in the Fuel System (DFI) chapter)
Intake Air Pressure Sensor #1 Connector [A]
Remove the intake air ...
Brake Hose and Pipe Replacement
NOTICE
Brake fluid quickly ruins painted plastic surfaces;
any spilled fluid should be completely washed away
immediately.
Remove:
Upper Fairing Assembly (see Upper Fairing Assembly
Removal in the Frame chapter)
Brake Hose Fitting Bolt [A]
Brake Hose Banjo Bolts [B]
Bolt [C]
Clamp ...