Hydraulic Breaker Bushing Pins & Lock Pins

Q1: What happens when a bushing pin shears or fails inside the front head?

A: When a bushing pin snaps, the inner lower bushing loses its lock and begins to rotate inside the front head. As it spins, the grease holes on the bushing shift away from the front head grease nipple. Once grease flow is blocked, the chisel and bushing run dry, causing extreme heat, galling, and total bushing burnout within hours.

Q2: How can I tell if a broken bushing pin has caused grease port blockage?

A: If grease pumps out from around the front head threads or grease nipple base rather than flowing down the chisel shank during daily lubrication, the bushing has likely rotated due to a sheared or missing bushing pin.

Q3: Why do cheap cylindrical bushing pins deform or break so quickly?

A: Inferior bushing pins are often made from unhardened carbon steel or lack proper carburizing. Under high vibration, soft pins develop flat spots or shear at the housing junction, allowing the bushing to shift and damage the inner wall of the front head.

Q4: What is the exact difference between a Bushing Pin and a Tool Retaining Pin?

A: A Bushing Pin is a smaller cylindrical pin designed specifically to lock the upper and lower bushings against rotation. A Tool Retaining Pin is a larger pin with a flat notch designed to catch the chisel shank and prevent the tool from falling out of the hammer.

Q5: Should I replace the bushing pins every time I install new bushings?

A: Yes. Installing new bushings with old, worn bushing pins allows micro-play. This play concentrates shear forces on the worn pin, leading to early pin fracture and premature damage to your new bushings.