I believe Delboy from Delboy's garage (Youtube) surrounded the o-ring area with a tiny amount of silicon sealant, which formed a tight seal when the two halves were tightened
Delboy's Garage, Suzuki Bandit Brake Caliper (Full Rebuild).
Obviously for a Suzi Bandit but same principle - forward to 19 mins 30 secs or thereabouts
Delboy's Garage, Suzuki Bandit Brake Caliper (Full Rebuild).
Obviously for a Suzi Bandit but same principle - forward to 19 mins 30 secs or thereabouts