All Balls Racing – Caliper Rebuild Kits, including rear caliper kits for the 21-23 Gas-Gas MC125 and the 2007 Gas-Gas MC125, and front caliper kits for the 84-86 Honda CR125R and the 21-23 Kawasaki KLX300 SM. Each kit carries the piston seals, dust boots and o-rings sized to the original caliper bore, so the piston slides straight and seals square instead of dragging on a swollen or nicked seal. Dirt bike calipers live in mud and pressure washer spray, and that combination is what kills them. Grit gets past a cracked dust boot, scores the piston, and the piston stops retracting fully. From there you get a pad that drags and cooks, a lever or pedal that goes soft as the fluid boils, and rotors glazed blue. A caliper rebuild kit costs a fraction of a new caliper and restores full piston travel, so pads release clean and bite hard on the next stop. Doing it alongside a fluid flush gets braking back to how the bike felt new. These brake caliper seal kits use fluid-compatible rubber rated for DOT 4. Bench bleed after assembly. Tell us your bike, year and front or rear and we will confirm the right kit before you order.