The new A1 service kit uses a set screw to hold the piston sleeve. The old service kit uses a circlip to hold the piston sleeve.

Rebuild video for set screw version

Service Kit for LH4 Lever and Caliper

• diaphragm
• piston
• front o-ring
• o-ring
• oil port o-ring (2)
• lever piston spring
• caliper piston o-ring (4)
• piston sleeve
• grub screw
• o-ring between caliper clamshells

• Lewis LH4 User Manual
• Bleeding tutorial (video)