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Chocking and Blocking Equipment

Equipment that is not held in place can roll, slip or drop. Chocking and blocking add physical barriers, but they must be the right kind and used the right way.

What is the difference between chocking and blocking?

Chocking means placing wedge-shaped blocks against wheels to keep a machine from rolling. Blocking or cribbing means using solid supports to hold up a raised part, such as an implement, a wagon tongue or a machine frame, so it cannot fall.

Both are secondary protection. They do not replace the parking brake, the shutdown routine or the manufacturer's service procedures.

Many farm injuries involving rolling and falling equipment are preventable with the right habits. Learning the vocabulary makes it easier to talk about these controls with workers and service providers.

When do you need them?

Consider chocks when parking on any slope, when disconnecting trailers or wagons, when servicing near wheels, and any time a machine could move unexpectedly. Consider blocking whenever someone needs to be near a part that has been raised.

The manual for each machine can tell you where it can be safely supported. Requirements and best practices differ by equipment, so confirm with the manufacturer and the official safety sources.

Think ahead. If a task will take you near a raised part, bring the supports to the machine before you begin, not after you are already under it. If you are unsure whether a method is acceptable, stop and ask. Extension safety specialists, equipment dealers and OSHA's agriculture resources are good places to start.

• Parking on slopes
• Uncoupling trailers and wagons
• Working beside or beneath raised parts
• Storing equipment for long periods

Why are hydraulics not enough?

Hydraulic cylinders can leak down or fail. A raised loader, hopper or implement that appears stable can drop without warning. People have been crushed beneath equipment that was supported only by its own hydraulics.

This is one of the clearest hazards covered in agricultural safety guidance, and NIOSH and OSHA both publish information worth reading.

A small leak in a seal can let a cylinder settle slowly or suddenly. That is why people who service equipment commonly use mechanical supports, and why manufacturers describe their own recommended methods in the manual.

What makes a good block?

Proper blocking material is solid, stable and suited to the load. Concrete blocks with voids, bricks, cinder blocks, rusty drums or random scraps can crack or shift. Wood must be sound and sized for the job, but the specific size and type depend on the load.

Ask the manufacturer or an extension specialist what supports they recommend. This page cannot give ratings or sizes.

Keep proper supports in the shop where they are easy to find. When the right blocks are handy, people are less tempted to grab whatever is nearby.

How do you place chocks safely?

Place them snugly against the tire on the downhill side, and on both sides when the manual or conditions call for it. Make sure the ground is firm and the chock cannot slide. Check them again before leaving the machine.

Do not stand in the path of a rolling machine when placing chocks. Set the parking brake first.

On soft or sloping ground, chocks may not be enough. Move the machine to firm, level ground when you can, and follow the manual for parking and securing.

What mistakes are common?

Using the wrong material, relying on a single small block, working under a raised implement without supports, and forgetting to remove chocks before driving off are all frequent mistakes.

A simple walk-around before moving a machine, checking for chocks, blocks and people, catches many of them.

Include chocks and blocks in the inspection routine. Replace cracked or worn items, and teach every new person how to use them.

Where can you learn more?

Use your operator manuals, OSHA's agriculture page and the NIOSH agriculture program. Hands-on training from your extension office or equipment dealer is valuable. If someone is trapped or crushed, call 911 and do not attempt an improvised rescue.

Share what you learn. A short talk at the start of the season about chocks, blocks and raised equipment gives new workers a chance to ask questions, and gives experienced ones a reason to check their own habits.

Last reviewed: November 12, 2026. Written by the Farm Safety Editorial Team. See our editorial policy.