Ride-on or walk-behind, a trencher is the machine you need for digging phone, cable, TV or electrical trenches as well as plumbing and irrigation trenches. But you can dig yourself into some downtime, or reduced equipment performance, if you don’t properly maintain the machine.

Regular maintenance not only helps you maintain productivity but also extends the useful life of the equipment. It also contributes to trencher safety.

Adopt basic maintenance best practices

When you perform inspections and maintenance tasks, pay attention to any safety precautions outlined in the owner’s manual. Turn the machine off first (except when checking engine gauges) and wear the appropriate PPE for the task, including work gloves and work boots.

1. Inspect the trencher before each use. Look for signs of wear and tear. Frequent inspections will help you spot trencher problems early. Specific components to inspect are outlined later in this article.
    
2. Keep up with preventive maintenance tasks. Most manufacturers specify preventive maintenance, including engine oil and filter inspections and changes, at 10, 50, 100, 250 and 500 hours of operation. Follow the schedule in the owner’s manual.
    
3. Check and change the oil regularly. Some trenchers require an oil change after 10, 20 and 100 hours of use. The user’s manual will spell out the intervals. Use oils and coolants recommended by the manufacturer and maintain recommended levels.
    
4. Lubricate if needed. If the machine requires it, lube necessary parts with a small amount of multipurpose grease after each use. Depending on your trencher, that may include the pivot head shaft bearing, the pivot bushing, the auger bearing, wheel tracks and tail roller. Manufacturers are increasingly using sealed bearings on pivot points to reduce lubrication needs.
    
5. Clean the trencher, including the chain, often. Some dense soils, such as clay soil, are relatively easy to remove when moist but become cement-like when given time to dry.
    
6. Check the air filter regularly. When working in dusty conditions, check it daily.

If you need help maintaining a large fleet, contact the United Rentals' Customer Equipment Solutions team. Tiered offerings include an on-demand inspection, maintenance and repair plan and a managed maintenance plan that includes ongoing preventive maintenance and inspections.

Inspect the trencher chain, teeth and sprockets

The digging chain, digging teeth and sprockets of the trencher are the primary wear parts, and they require regular inspection. Visually inspect all three after each job or roughly 10 hours of operation.

Follow the manufacturer’s specifications for matching the digging teeth, sprockets and digging chain to the digging conditions. If you’re working in rocky or sandy soil, you’ll need to replace the teeth, chain and sprockets more often.

Trencher chain

Follow the manufacturer’s recommendation on chain tension and check the chain tension before and after each use. As a general rule, you should be able to fit two fingers between the chain and the lowest part of the boom when the boom is parallel to the ground. A chain that’s too tight causes premature wear on the rollers, boom and sprockets. A loose chain can cause the equipment to vibrate, and it may hit the boom and eventually bind the tail roller.

Also inspect the chain for wear. A worn digging chain can jump off the sprockets or end roller and damage other parts of the digging system.

Trencher teeth

One of the most common trencher maintenance mistakes is not replacing digging teeth often enough. Digging teeth should be sharp. Worn teeth force the trencher to work harder because they create higher shock loads on the chain and boom.

Check that the face of each cutting edge is intact. Broken teeth should be replaced right away.

Different types of teeth work best in specific situations. Cup teeth work well in soft, medium or sticky soils. Tougher teeth with carbide bits work better in rocky soil or frozen ground. Choosing the right teeth for the soil reduces stress on the trencher.

Trencher sprockets

When you find worn sprockets, replace them and the chain at the same time to maintain the system tolerance and increase the life of the machine. If you replace one and not the other, the newer component will be impacted by the worn one and degrade faster.

Inspect the trencher tires, fluids and gauges

The tires, fluids and gauges of a trencher are often overlooked, but they are critical to ensuring good performance.

Trencher tires

Check the tire pressure. You’ll also want to tighten the tire mounting bolts to the manufacturer’s specifications since the stress of digging loosens them.

Trencher fluids

Check the levels of hydraulic fluids, engine oils and coolants, and look for leaks while you’re at it.

Eyeball the hydraulic hoses for weathering, damage or bulges that can lead to bursting under pressure.

Trencher gauges

Start the engine and check each gauge. All temperatures and pressures should rise to levels specified in the user’s manual and remain there. If you get any abnormal readings, shut down the trencher and remove the machine from service until the problem has been fixed.

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