How to Free Frozen Pins in Heavy Equipmentby Cody Sorensen
Pins used to hold pieces of heavy equipment together wear and rust over time. This wear and tear causes the pins to often get stuck. To free a frozen pin in heavy equipment more than physical strength is needed. Rust often causes metal to metal surfaces to bind together. If you start trying to pound the pin out without first attacking the rust, you may just end up bending or mushrooming the ends of the pin. Once this happens, the pin must be ground, reamed or cut out.
Release all hydraulic and mechanical pressures bearing down on the pin, if applicable. Many pins won't have either of these two pressure loads. The way these pressures are released, will depend on the type of equipment being repaired.
Saturate all exposed areas of the pin with rust penetrating oil. This is usually squirted onto the pin's surface. Allow the oil to sit on the pin for 24 hours.
Scrub the exposed areas of the pin with a wire brush to help work the oil into the pin hole. Apply another coating of rust penetrating oil.
Grip the head of the pin with a pipe wrench. The wrench size used will depend on the size of the pin head. Twist the pin back and forth with the wrench until it spins freely inside the pin hole. This may take several coatings of oil and several twisting attempts.
Remove the cotter pin with a pair of pliers. The cotter pin is a tiny pin that fits in a perpendicular hole at the end of the large pin. This keeps the pin from coming out of the pin hole during operation.
Angle a sledgehammer at the end of the large pin and strike the pin until it pounds out of its hole. Pull the pin the rest of the way out with the pipe wrench.
- Wear safety glasses, leather work gloves and a hard hat when working on large machinery.
Items you will need
- Rust-penetrating oil
- Pipe wrench
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