Check for mismatched tread patterns, uneven tread depth, and sidewall/tread cuts.
Used machines are smart ways to complement or round out your fleet — and if you know what to look for (and ask about), you can feel more confident that the equipment you purchased will be with you out in the field and not in the shop.
It's never a guarantee, obviously, but here are some tips on inspecting some of the more critical components on a used machine to ensure its condition is in line with the asking price:
Ask Who Owned the Machine: It's not uncommon for buyers to ask who owned the machine, where it was used, and in what application — so don't hold back. Knowing upfront where and how it was used helps you know what to inspect more thoroughly. For example, if the machine was used in a caustic operation, you'll want to look for excessive corrosion. Corrosion usually begins forming under fender wells, on hose fittings, under loader frames, on rims, and on the underside of frames. Machines used in scrap, waste and logging tend to incur more abuse and wear, so you'll want to closely inspect components like the tires and transmission. If a crawler excavator was operated in sand versus dirt, that will put more wear on the undercarriage. Always start by asking where and how the machine was used to determine how the rest of your inspection will go.
Tires: This short video from Volvo Construction Equipment has some good tips on properly inspecting the tires on wheel loaders. Similar to loaders, artic truck tires need the same evaluation. Check for mismatched tread patterns, uneven tread depth, and sidewall/tread cuts.
Transmission: Most transmissions will last up to around 8,000 hours before you start having to make repairs. One thing you always want to check for is leaks, but you also need to operate the machine to make sure it's shifting the way it's supposed to. The only way to do that is to have ample room to actually drive and shift the machine. If a transmission doesn't shift out, it could be that the differential lock got disengaged, or sometimes it's a bad sensor and the computer just needs to be calibrated.
Engine: If you can, get a service history to know what's been replaced and when. While you can easily get 10,000 hours out of an engine, it's usually around 5,000 or 6,000 hours that you start having to replace things like rings, bearings, etc. Always check for leaks and be sure to look for signs like coolant in the water or metal in the oil.
Undercarriage: This excavator walkaround video has good tips on properly inspecting an undercarriage. The expected life of an excavator's undercarriage will vary greatly depending on how it was used. For example, excavators working on a slope tend to produce more wear on one side than the other. Be sure to check for corrosion and pitting on roller frames and the undercarriage — corrosion over time will make the metal more brittle. Undercarriages on large highway projects or pipeline applications generally experience greater wear due to increased traveling. When possible, the most accurate way to evaluate undercarriages is to measure them. You'll need the conversion charts for each brand to convert them to percent worn.
Some additional things you can look for:
- One telltale sign that the undercarriage is starting to get worn out is the sprocket— the thinner the teeth get, the more wear they have. If they get to a point where it looks like you could shave with them, they're worn out. And if they are, that's usually a pretty good indicator that the rest of the link assembly likely needs to be replaced. Note: You can put new sprockets on used rails, but you cannot run worn sprockets on new rails.
- Be sure to measure the pins and bushings to see if they're stretched out. Bushings have both internal and external wear. External wear can be felt by running your hand over the bushing in between the links. Internal wear can be visible by looking at the position of the track adjuster. Eventually the bushings and pins will stretch so much the track adjuster will no longer remove any slack for the rail. You also should check for any external cracking and waving. If one has a wave, that means the bottom of that link has a lot of wear. You also can count the links to see if one was removed from the link assembly in an effort to tighten the undercarriage. If someone has made it too tight, that will spell trouble in the near future.
- Check the condition of the bushings. Typically, bushings are under considerable load at the sprocket's six-o'clock position, and that wear will distort bushings over time. Feel if the bushings are U-shaped versus circular. If you reach up and feel past the bushing and touch or see the pin that's in the center, they're worn out.
Drop Box: You can expect to get 7,000 to 8,000 hours out of a drop box. If one's up there in hours, check for any leaks and excessive noises like grinding. You'll hear grinding or popping when a gear inside starts going bad. A new drop box can cost around $40,000 or $50,000, so it's worth a thorough inspection.
Axles/Differentials: These will usually last 10,000 to 12,000 hours before you start having any problems. The biggest issue you could have is external cracking, holes and leaks. With planetaries on articulated haulers, there's a mark that states where it's level to make sure they're not overfilled with oil which can indicate accidental overfilling or a failing seal causing a brake leak.
The life of components on a used machine will always vary depending on how the machine was used, so asking about its previous use and requesting a service history will give you a good starting point before you start a machine inspection.