Inertia coupling maintenance
CAUTION! OVERCENTRE HANDBRAKES MUST BE SECURED IN A SAFE POSITION PRIOR TO UNDERTAKING ANY MAINTENANCE!
Coupling mounting bolts - check for tightness. 12mm 8.8ht bolts should be 76 to 80Nm torque.
Coupling head bolts - check for tightness. 12mm 8.8ht bolts should be 76 to 80Nm torque.
Visually check for stress cracking of the coupling body around the mounting bolts (Most likely on pressed steel bodies).
Coupling head - using a new 50mm towball (to meetBSAU 113c it must be between 49.61mm and 50.00mm) check that it locates and locks correctly in the coupling head and that any wear/location indicators are functioning. Lubricate the mechanism and lightly grease inside the coupling socket.
Draw tube - check, by moving the shaft up and down, that the bearings that support the draw tube are not worn. The amount of end float between the shaft and the brake lever that is acceptable varies between manufacturers and should be checked in their service instructions
Drawtube gaiter - check for splits and tears. Replace if damaged.
Damper - with the handbrake tied down and wheels chocked, push the coupling in by hand. It should move in steadily with uniform resistance. A damper with no resistance at all or conversely, very high resistance but flies out when released is faulty. Replace immediately. N.B. it is essential that the correct specification of replacement damper is used and that manufacturers' fitting instructions are followed.
Handbrake - check the action for correct movement. All modern inertia couplings are designed for auto-reverse brakes. The handbrake assembly will include an energy store that is under high pressure. DO NOT REMOVE! WARNING! Do not operate the handbrake unless the coupling is connected to a complete brake linkage. If not connected, the handbrake MUST be tied down.
Lubricate the pivots, including any grease nipples underneath.
Grease nipples - apply a grease gun to nipples on top of the housing, ensuring that a liberal amount of grease is applied.
Breakaway cable - check for kinks, fraying, operation of the clip and that the cable is securely attached to the "burst" ring. If replacement is required, ensure that a genuine part is used. It is essential that the cable passes through a hole or guide near the front of the coupling to ensure it’s final pull is in a straight line in the event of a breakaway.