Like most replacement parts, digging chains vary in price and quality. Wren suggests looking past the initial purchase price and asking how the chain is made, what type of material it is made of and the expected life of the chain. “A higher quality chain may cost more initially, but will last longer. Digging chains are not created equal and vary in durability as well as performance,” he emphasizes.
Inspect the Engine and Hydrostatic System
The engine and hydrostatic system are expensive parts of any trencher and should be carefully inspected before purchasing a used machine.
“When starting the engine, listen and pay attention to how it sounds,” says Collins. “An engine can knock and blow smoke. There are various little things you can hear if it’s not finely tuned and running smoothly.
“Check the engine oil for the proper amount and if moisture exists,” he continues. “Check the air filter for telltale signs of abuse or neglect. Remove the air filter and inspect down the inlet to see if there is a dust trail.”
“Take pressure readings to see if the motor is producing the amount of output it should,” Kuyers advises. He also suggests checking the main hydraulic pump drive by taking oil samples and putting pressure gauges in the system to check that the readings are up to spec.
“Since almost all of today’s trenchers are hydrostatic, it would be wise to have an oil analysis report,” agrees Wren. “This will reveal the condition of the hydrostatic pumps and motors. If there are metal particles in the oil, it’s a clue to pass on purchasing the unit.”
“If pressure readings are poor or the hydraulic pumps have failed or are beyond their useful life, it is expensive to rebuild or replace them,” says Kuyers. “It’s not worth the risk. Consider buying a new machine if trenching is the cornerstone of your business.”
Of course, there is no better way to know how a machine will perform than to operate it. “When operating the trencher, make sure to listen to it. Put it in the ground… Trench with it,” Collins stresses.
When operating the trencher, pay close attention to the chain. “If the chain stalls frequently, it means the hydraulic pressures aren’t correct or the pumps are not working properly,” says Kuyers.
“By operating a used trencher, you’ll be able to see how all the controls work – how the steering feels, if any of the hydraulic cylinders are leaking or if the backfill blade is loose,” says Wren. “Paying close attention to how a trencher sounds, feels and looks can clue you in to how the machine was maintained and its current condition.”
How Well Was It Maintained?
The overall appearance of any used piece of equipment is an indicator as to how it was maintained. Check for bent metal, missing decals, scratches, dents and, most importantly, grease.
“Trenchers take a lot of abuse by the nature of the job they perform,” says Kuyers. “However, despite any cosmetic scratches, you should see telltale signs of grease.”
Some of the common failure points on a trencher are due to lack of lubrication. Regular greasing of the bearings on the sprocket, end idler bearings and trencher pivot points is required. “Looking at the grease fittings provides an excellent indication of how the machine has been serviced,” says Wren.
“Grease is the lifeblood of any trencher,” Collins adds. “Review the service points of the machine, making sure grease appears where there should be grease.”
If possible, obtain maintenance records for the machine. “If you are able to secure maintenance records on a used trencher, it is a telltale sign the previous owner has taken care of the equipment,” says Collins. He notes that dealers or rental stores often have detailed maintenance records for each piece of used equipment they sell.
If records exist, compare them with the hour meter readings and the age of the machine. Records should show that the machine has been maintained on a consistent basis. “Knowing who the previous owner was and how the machine was used is also helpful,” says Wren.
“From an engine and hydrostatic system perspective, it’s imperative to find out maintenance information from the previous owner,” says Kuyers. “These are big-dollar items and worth knowing more about.”