Breaker Bushing Pin Care & Troubleshooting

Bushing pins (bushing lock pins) play a vital role in protecting your breaker's front head: they index and lock the upper and lower bushings in place to maintain open grease channels.

Failures Directly Caused by Bushing Pin Breakdown

• Grease Hole Misalignment & Lubrication Starvation: When a pin shears, the bushing rotates. The grease passage on the bushing shifts away from the grease nipple. Grease can no longer reach the chisel shank, leading to dry friction.

• Bushing & Chisel Heat Fusion (Burnout): Without grease, temperatures between the chisel and lower bushing exceed 300℃. The metals score, gall, and eventually fuse together, destroying both components.

• Front Head Bore Ovalization: A broken or undersized pin allows the bushing to vibrate and slap against the front head inner wall, turning the round housing bore into an oval shape and requiring expensive re-boring.

Troubleshooting & Prevention Protocol

1. Check Grease Flow Daily: When applying grease, confirm that fresh lubricant extrudes smoothly down the chisel shank. If grease backs up around the fitting, stop work—the bushing has rotated due to a sheared pin.

2. Inspect Pins During Bushing Service: Whenever replacing chisels or bushings, pull the bushing pins and inspect for stepped wear, shearing marks, or bending. Replace any pin showing flat spots exceeding 1 mm.

3. Never Drive a Breaker Without Bushing Pins: Operating without lock pins allows immediate bushing rotation, permanently damaging front head grease ports.

4. Use Dual-Hardness Carburized Pins: Always select replacement pins featuring a carburized surface (HRC 56–62) and a shock-absorbing core (HRC 32–40).

SLYM Quality Assurance

SLYM manufactures replacement bushing pins from 20CrMnTi alloy steel, precision-ground to micron tolerances. SLYM lock pins prevent bushing rotation, keep grease channels aligned, and safeguard your front head from costly repairs.

Need OEM replacement bushing pins or technical support? Contact SLYM Machinery directly at info@slymmachinery.com.