A leaf spring shackle is usually mounted at the rear of the leaf spring and this has two functions, it mounts the spring to the chassis and it allows for the vertical movement of the spring.
When a vehicle is fitted with leaf springs, they are mounted to the chassis using a fixed pin(usually at the front) and a swinging shackle (usually fitted to the rear of the spring).
As the vehicle traverses over uneven road surfaces, the leaf spring flexes. The leaf spring is designed with an amount of camber, this is the arc of the spring.
When the spring moves upwards it has a tendency to flatten out and inturn, this will increase its length, to allow for this a swinging shackle is fitted.
Pedders Shackle kits are a heavy duty replacement fitted with grease nipples to allow “in-situ” greasing of polyurethane bushes.