Rebuilt Machines
Brooke Wisdom | April 1, 2011

Track-type tractors

New, used and rental aren’t your only options

By Tom Jackson

Mechanically speaking, rebuilding an older bulldozer from the ground up is a lot of work, but relatively straightforward. There are seven or eight major component groups, depending on what you count, that can be pulled and replaced with new or rebuilt components.

When this Cat D8L was brought in (left picture), it had more than 25,000 hours after being used by a utility company to work their coal stockpile. (The ROPS was removed for transportation purposes.) At right, the rebuilt machine prior to shipping.

The challenge is figuring out if a rebuild is the right thing to do financially. “Customers are looking for ways to get more value for their money,” says Philip Ringenberger, senior marketing consultant for Caterpillar’s Certified Rebuild program. “They have to make the decision to keep fixing it, or replace it, but the rebuild program gives them some distinctively different options.”

Traditionally, the options facing a contractor with an aging dozer (Cat prefers the term “track type tractor”) include: buying new, buying a low-hour used (3,000 to 5,000 hours) machine, dealer rebuilds, or rental.


“Caterpillar’s Certified Rebuild and Certified Power Train rebuild give the customer a couple more choices at some unique price points,” Ringenberger says. “It fills in some of the gaps between other pieces of iron that might work for that customer on that day.”

Decision points

Dozers are expensive machines and rebuilding one is not cheap. That makes it important for you to have clear goals for doing a rebuild. For that reason most contractors who opt for the rebuild will put the dozer back into full production, rather than use it as a backup or utility machine, Ringenberger says.

Doing a rebuild for a machine you only plan to keep another year also might not be the best financial decision, he says. If you spend the money to rebuild a dozer with 12,000 hours on it, in most cases you need to put another 12,000 hours on the rebuilt machine to get your full value out of the rebuild. “You’ve paid a premium price for a machine that can be rebuilt, and you can extract more of that value from the machine if you rebuild it, but you have to consume that value yourself.”

The D8L had all wiring harnesses replaced, as well as every component tested.

Ringenberger characterizes the rebuilds as a niche product. “A CCR is not the answer for every track type tractor in every application, but there are a lot of people who fit in that niche. As a general rule that tends to be people with high production, high availability and high hour needs.”

Likely candidates

The decision to rebuild a dozer doesn’t line up with any set number of hours or years for the machine. Ringenberger uses 12,000 hours as a reference point but that can vary depending on the severity of the application and other factors.

Stripped down to the frame, the Cat D8L had all major components either rebuilt or replaced. Before being rebuilt, the frame was inspected, repaired, sanded and repainted.

“Each rebuild is a unique,” Ringenberger says. “There are many variables that must be considered such as application, future expectations for that machine, cost, etc. The major components are tested to determine their overall condition, and the solution for any given component is determined by what is the best for the customer at that time on that machine. There may be times when the component can easily be rebuilt to like-new specs. There may be other situations where there are significant problems with that component that might make it more efficient to replace the component with a remanufactured item or a new item. This is determined by the dealer and the end user customer. There are no hard and fast rules.”

Timing is key

The components of a dozer are designed as a system to wear out at roughly the same rates, but this doesn’t happen on a predictable basis. Different applications, environments and load factors have different effects on engines, hydraulics and other components.

Technicians repaired and rebuilt the blade.

“Sometimes customers will just rebuild the engine and put it back in the old track-type tractor with an old transmission and an old torque converter,” Ringenberger. “They’ve got a nice new, tight engine, but you can bet the farm in the next few hundred or thousand hours that engine is going to take the transmission out. Then you fix the transmission and who knows what may be next – the torque converter, final drive or a differential.”

For contractors whose work requires high production levels, the rebuild downtime can be a critical factor. Trailering a key machine back to the shop for numerous individual rebuilds can cause expensive delays on jobs. “Once a machine has progressed to the point where there are issues with multiple components it might just be best to do all of them at the same time,” Ringenberger says. “This can minimize the number of times the machine is taken out of production for repairs. You want to take it down one time. Plan it, schedule it, fix everything and get back to work.”

Emissions upgrades and Tier 4


If you work in a region of the country with strict off-road diesel emissions regulations, you might have an additional reason to rebuild an existing dozer. Many contractors in California, and parts of New York and Illinois add exhaust retrofit devices or repower their machines with a newer, cleaner engine to meet emissions requirements or bid on publically funded jobs.

“If you do an emissions repower at the same time as a rebuild it can save you a bit of labor,” Ringenberger says. “You don’t just drop one of those engines in. It’s a heck of a job to fit all the stuff you need in there. You might have to make some modifications to the cab, frame or engine mounts. And if you have the machine torn down already it gives you some elbow room to work.”


Tier 4 Interim engines will start appearing on many dozers in 2012, followed by Tier 4 Final engines in 2014. Because these engines are expected to cost more, this may be an additional incentive for contractors to consider rebuilding their existing dozers with Tier 3 engines. EW

CCR or CPT: what’s the difference?

A Caterpillar Certified Rebuild (CCR) is a complete remanufacture of the dozer to the original factory specs by the local dealer. The machine is torn down to the frame and rebuilt from the ground up with rebuilt or new components. When finished, the rebuilt dozer is as good or in some cases actually better than when it originally left the factory, Cat’s Philip Ringenberger says. Improvements to the original come when engineering updates that have occurred since the original date of manufacturer are included in the rebuild.

A Caterpillar Power Train rebuild covers everything that makes the machine, go, stop and stay cool, plus a couple electronic control modules and some wiring harnesses. What is not covered in the CPT are hydraulics and aesthetics: the cab, paint, sheet metal and glass, unless otherwise directed.

“The parts of the machine that make you money are in the powertrain,” Ringenberger says, “so the CPT is still a comprehensive bit of work. Sometimes they’ll do the CPT and a little work on the cab or hydraulics, what the dealers call a CPT-plus. That enables the dealer and customer to customize the rebuild. It won’t be as much as a full CCR but a little more than the basic CPT.”

Undercarriage rebuilds are treated as a separate item in both scenarios since these are rebuilt several times before the engine or drivetrain are nearing the end of their lifecycles.

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