A thorough inspection helps you find hidden problems in a used excavator. You can spot common problems with the equipment before you buy it. Your check of the equipment should cover several key areas.
Look for structural cracks and poor welds.
Examine the bucket, bucket teeth, bucket pins, bucket linkage, and the bucket structure.
Check for hydraulic leaks during operation.
Listen for unusual engine or pump noises.
Verify the maintenance history.
This process helps avoid future problems and ensures the excavator’s safety.
Phase 1: The Static Walk-Around Inspection
Your first step is a detailed walk-around inspection with the engine off. This initial review helps you find major issues before you even start the machine. A proper equipment inspection at this stage can save you from expensive mechanical failures later.
Frame, Boom, and Stick Integrity
You should begin by examining the excavator's main structure. The boom, stick, and frame handle immense stress during operation. Hidden structural damage is a serious safety risk and can lead to catastrophic breakdowns. Look closely at all connection points, especially where the boom meets the main body and where the stick connects to the boom and the bucket.
Pay special attention to any welds. A previous repair can be a red flag if not done correctly. You can often tell the difference between a quality repair and a quick fix.
Feature | Unprofessional Weld | |
|---|---|---|
Bead Appearance | Smooth and uniform | Irregular, with pits or craters |
Tie-In | Blends smoothly into the metal | Creates a sharp edge or undercut |
Spatter | Minimal | Excessive spatter around the weld |
Defects | No visible cracks or holes | Obvious cracks or porosity |
Also, search for signs of stress that might indicate deeper problems. Even small clues can point to significant structural damage on the equipment.
Look for hairline cracks in the paint.
Watch for rust streaks coming from joints or welds.
Check for any bulges or deformations in the steel plates.
Examine the areas around the bucket pins and main joints for cracks.
Uncovering Common Problems in the Undercarriage
The undercarriage of an excavator accounts for a huge portion of its maintenance cost. Worn components affect the machine's stability, increase fuel use, and can be very expensive to replace. A full undercarriage replacement can cost over $15,000, so this area needs your full attention.
You need to measure key components for wear. Use tools like calipers and a depth gauge to check the following parts. As a general rule, a component may need replacement when it is worn down by about one-third of its original size.
Tip: You can find the specific wear measurements for the equipment in its technical manual. Comparing your measurements to the manufacturer's chart will tell you the exact percentage of wear.
Walk around the entire track system. Check the track pads, rollers, and sprockets for damage. Look for missing bolts or cracked links. A worn-out undercarriage is one of the most common problems you will find on a used excavator. This can lead to serious mechanical issues if not addressed.
Identifying Hydraulic Leaks and Fluid Issues
Hydraulic system failures are another major concern. The hydraulic system is the muscle of the excavator, powering the boom, stick, and bucket. Start by visually checking all hydraulic components for leaks.
Common leak locations include:
Hoses and their connection points
The swing motor area
The main hydraulic pump housing
Next, you should check the hydraulic fluid itself. Find the hydraulic tank and check the fluid level on the sight glass or dipstick. Clean fluid is typically clear or amber.
Note: Milky fluid indicates water contamination, which can cause rust and damage the pump. Dark or burnt-smelling fluid signals that the oil has broken down and is no longer protecting the mechanical parts of the system.
Contaminated fluid can lead to slow operation and damage sensitive components, making this a critical part of your inspection. A healthy hydraulic system is essential for the excavator to perform its job correctly.
Phase 2: Inspecting the Bucket and Attachments
The bucket and its related components do the heavy lifting. Wear and tear in this area is normal, but you must know how to tell the difference between acceptable wear and a critical failure waiting to happen. A careful check of the bucket attachment can prevent major excavator bucket problems.
Solving Excavator Bucket Problems Before They Start
You should inspect the bucket for signs of damage and excessive wear. A damaged bucket reduces digging efficiency and can compromise the safety of the equipment. Even small cracks can grow quickly, leading to a sudden failure of the bucket. Look for any bends or warping in the steel plates, as this indicates structural fatigue.
Pay close attention to the teeth and cutting edge of the bucket. These are the first points of contact with the ground. You should look for these signs of wear:
A worn-out bucket is one of the most common problems you will find on a used excavator. Addressing these issues early is much cheaper than replacing the entire bucket later.
Checking Pins, Bushings, and Couplers
Pins and bushings connect the bucket to the stick and hydraulic cylinders. Worn connections create "slop" or excessive movement. This reduces digging accuracy and puts extra stress on the entire structure. To check for wear, have someone slowly curl the bucket while you watch the connection points.
Pro Tip: A small amount of play is normal. A new pin and bushing might have a clearance of around 0.010 to 0.015 inches to allow for grease. Anything more than a slight wiggle suggests significant wear.
If the excavator has a quick coupler, check its condition. Look for visible cracks, corrosion, or hydraulic leaks. A failing coupler may be difficult to connect or make strange noises during operation. This is a critical safety component of the equipment.
Examining Auxiliary Hydraulic Lines
Many excavators have extra hydraulic lines to power attachments like hammers or thumbs. You need to inspect these lines carefully. Look for any fluid leaks, especially around fittings and connections. Damaged O-rings or loose fittings are frequent sources of leaks. Check the hoses for cracks, bulges, or abrasions. Damaged auxiliary lines can disable an expensive attachment and cause hydraulic system contamination.
Phase 3: The Operational Test of the Excavator
After your walk-around, it is time to start the engine. The operational test reveals how the excavator performs under real working conditions. This phase is crucial for uncovering hidden mechanical issues that are not visible when the machine is off. Proper pre-operation inspections and a thorough operational test can prevent costly mechanical failures.
Engine Startup and Exhaust Analysis
You should start the engine from a cold state if possible. Listen carefully as it turns over and idles. Some older diesel engines make loud noises on a cold start, especially in low temperatures. This noise might disappear once the engine is warm. However, a persistent knocking or banging sound points to a serious internal problem.
Next, you need to analyze the exhaust smoke. The color of the smoke is a direct indicator of the engine's health. You can learn a lot about the engine's condition from a quick look.
Black Smoke: This means the engine is getting too much fuel or not enough air. It points to issues like faulty injectors, a clogged air filter, or a turbocharger problem. This condition reduces engine efficiency.
Blue or Grey Smoke: This color tells you the engine is burning oil. This is a mechanical problem. It could be caused by worn piston rings, bad valve seals, or a faulty turbo seal. You will often smell burning oil with this smoke.
White Smoke: A little thin white vapor on a cold day is just condensation. Thick, persistent white smoke is a major red flag. It often means the engine is burning coolant from a blown head gasket or has unburnt fuel passing into the exhaust due to low compression or bad injectors.
Let the equipment warm up to its normal operating temperature. Listen for any new noises that appear as the engine heats up. A healthy engine should run smoothly without any loud or unusual sounds during operation.
Testing Hydraulic Speed and Power Under Load
The hydraulic system gives the excavator its power. You must test its speed and strength. First, cycle all the hydraulic functions. Raise and lower the boom, extend and retract the stick, and curl and uncurl the bucket. All movements should be smooth and responsive. Sluggish or jerky operation signals a problem with the hydraulic pump or valves.
You also need to check for hydraulic drift. This happens when a cylinder cannot hold its position under load. A drifting boom or bucket is a safety hazard and hurts productivity.
Raise the boom so the bucket is several feet off the ground.
Extend the stick straight out.
Shut off the engine.
Watch the boom, stick, and bucket for at least five minutes. They should not sink or drift downward. Any movement indicates an internal leak in the cylinders or control valve.
Finally, test the hydraulic power. If possible, dig into a pile of dirt or lift a heavy load with the bucket. The engine should not struggle or stall. If the machine feels weak, it may have a worn-out pump or relief valves that are set too low. This test also shows how the machine handles a load, which is important for avoiding issues related to overloading the excavator. Consistent power during operation is key. Overloading the excavator can cause long-term damage, so a strong system is vital.
Evaluating Swing and Travel Functions
The swing and travel functions are essential for the excavator's mobility and operation. Start by swinging the upper part of the machine left and right. The movement should be smooth and quiet.
Listen for specific noises from the swing bearing, which connects the upper structure to the undercarriage.
A grinding, popping, or clicking sound often means the bearing raceways are worn or lack grease.
A faint whine under a heavy load can be normal, but loud grinding is a sign of a problem.
Excessive play or movement when you stop the swing indicates significant wear.
Next, you must test the travel motors. Drive the equipment forward in a straight line for at least 50 feet. A machine that pulls to one side likely has a weak final drive motor or an issue in its travel system. You should also try driving up a small slope. Both tracks should pull with equal power. A weak track motor will struggle on an incline, which severely limits the machine's usefulness on a job site. This part of the operation test helps you understand the condition of the final drives, which are expensive to repair. Be cautious of overloading the excavator, as this can strain the entire drivetrain.
Phase 4: Prioritizing Operator Safety and Cab Condition
You must check the operator's cab for safety and functionality. A well-maintained cab protects the operator from accidents and injuries. It also shows how the previous owner cared for the equipment. Following proper safety protocols is essential to prevent accidents.
Inspecting the Cab for Safety Features
You should first inspect the cab's protective structures. These features are your main defense against serious accidents and injuries. The excavator should have systems to protect you from rollovers and falling objects. These hazards are common on job sites.
System | Function |
|---|---|
ROPS (Roll Over Protection System) | Protects operators if the machine overturns, a frequent cause of accidents. |
FOPS (Falling Object Protective Structure) | Shields operators from falling objects like rocks or tools, reducing injuries. |
Check these structures for any cracks, bends, or unauthorized modifications. Damaged safety structures fail to prevent accidents and injuries. While OSHA does not require seatbelts in all excavators, you should check for one. A working seatbelt adds another layer of safety and helps prevent injuries during sudden stops or rollovers. Adhering to safety protocols minimizes hazards.
Verifying Controls, Gauges, and Electronics
Next, you need to test all the controls inside the cab. A functional dashboard is critical for safe operation. You should verify that every button, switch, and lever works correctly.
Check all gauges for proper function when the engine is on.
Test the horn, lights, and windshield wipers.
Ensure the main display screen is bright and shows no error codes.
Confirm the heater and air conditioner work for operator comfort.
Faulty electronics can hide serious mechanical problems. Correct operation of these components is part of good safety protocols.
Common Excavator Operating Mistakes to Look For
You can often see evidence of past excavator operating mistakes. These mistakes cause premature wear and lead to accidents and injuries. Inadequate training is a common reason for these mistakes. Look for signs of overloading the bucket. A bent or heavily damaged bucket suggests the operator frequently exceeded the machine's limits. This puts stress on the entire excavator.
Improper use of the bucket or other attachments also causes damage. These excavator operating mistakes shorten the machine's life. Comprehensive training helps operators avoid these common mistakes. Good training improves safety and long-term productivity. Avoiding excavator operating mistakes is key to preventing accidents and injuries. Following safety protocols during operation is the best way to avoid these mistakes.
Phase 5: Verifying History and Documentation
A machine's paperwork tells a story. You should review all available documents to understand the excavator's past. This final check helps you confirm the machine's condition and uncover potential long-term issues. Proper documentation provides a clear picture of the machine's history and its future reliability.
Scrutinizing Maintenance and Service Records
You must ask for the complete maintenance and service records. A detailed history shows a commitment to proper care. These records can reveal recurring problems and confirm that regular maintenance was performed. Look for consistent entries over the machine's life.
A good maintenance log should include:
The date and hours of operation at the time of service.
The type of maintenance performed, such as a routine check or a specific repair.
A list of all parts that were replaced.
Notes from the technician about their findings.
Consistent maintenance is key to a machine's longevity.
Cross-Referencing the Hour Meter
You should always compare the hour meter reading to the machine's overall condition. The physical wear on the pedals, joysticks, and seat should match the hours shown. On some older models, owners can easily tamper with or unplug the hour meter. A machine with low hours but a heavily worn cab or rotted base is a major red flag.
Condition is the most important factor you should consider. A paper trail of maintenance history from a dealer can help verify the hours. However, you should trust your physical inspection over the number on the meter.
Checking for Safety Bulletins and Recalls
You need to check for any open safety bulletins or recalls. Manufacturers issue these notices to address known defects or improve machine safety. You can get this information directly from the manufacturer's website or an authorized dealer. A service bulletin index provides an organized database of these updates. Checking for these bulletins ensures the machine is compliant with the latest safety standards and protects your investment. This step is critical for operator safety and preventing future failures.
A systematic inspection is your best defense against buying an excavator with expensive hidden problems. You can avoid common problems and costly mistakes by checking the equipment's structure and hydraulics during operation. Combining your physical inspection with the maintenance history helps you make a smart investment in this excavator. Avoid critical mistakes by checking for a worn bucket, a damaged bucket, or a weak bucket. Overlooking play in the bucket or a damaged bucket are mistakes that risk your safety and the equipment's reliability. This process prevents future problems and ensures your safety.
FAQ
What is the most important part to check on a used excavator?
You must check the bucket. A damaged bucket or a weak bucket causes many problems. A failing bucket can lead to serious accidents. Inspect the bucket teeth and the structure. A worn bucket is a common issue. The bucket needs a close look.
Why is operator training important?
Proper training prevents many accidents. Good training teaches operators to avoid mistakes that cause injuries. Untrained operators can damage the machine and cause accidents. Training is key to safety.
What happens if I ignore a small crack in the bucket?
A small crack in the bucket can grow quickly. This weakness can cause the bucket to fail during a lift. This failure leads to dangerous accidents and severe injuries. These accidents are preventable.
How does a worn bucket affect safety?
A worn bucket reduces control and stability. This can cause unexpected movements, leading to accidents and injuries. These accidents can cause serious harm. Ignoring a bad bucket leads to more accidents and injuries.
