ARB Air Locker Master Shim

The ARB Air Locker Master Shim is a precision differential shim made for installing and setting up ARB Air Locker air-operated locking differentials. It is also called an Air Locker shim or differential master shim. It is a thick, rigid spacer. During assembly, it sits between the Air Locker seal housing and the carrier bearing cup.

Key Features:

• Keeps the seal housing clear of the bearing cage, which helps protect the bearing during assembly and use
• Helps hold the thinner preload shims in place
• Helps keep the seal housing positioned so the air inlet stays between the two seal housing O-rings, which the locker needs in order to engage
• Used with ARB Air Locker shim kits for bearing preload and backlash setup
• Made by ARB to suit the Air Locker differential's design

ARB's installation instructions call for the master shim to be fitted with its rounded edge facing the correct way. Follow the instructions for your specific Air Locker. Proper shimming is important for the locker's sealing and bearing life.