Check the following items and replace if necessary.

Caliper
Check the cylinder inner wall for wear, cracks or damage.
■ CAUTION ■
Always clean with new brake fluid. Never clean with mineral oil such as gasoline and light oil. 
Piston
Check the piston surface for wear, cracks or damage.
■ CAUTION ■
A piston sliding surface is plated. Never polish with sandpaper. 
Pad Pin
- Check the piston pin for corrosion, wear, cracks or damage.
- Check the metal bushing of pad pin for settling and damage.

Cross Spring
Check the cross spring for wear, cracks or damage.