April 1, 2008
by Dave Drzewiecki and Michael Stec
When it comes to repairing an automobile, a good mechanic can oftentimes save you money in the long run. The same can be said for a good, trained service technician when it comes to keeping heavy equipment — the lifeblood of our operations — in top working order.
In today’s world, where machines have expensive price tags, extensive electronics, and are technologically advanced, it’s not wise to have “just anyone” service your machine. More damage than good would likely be the outcome.
Most major manufacturers offer service training at both the dealer and customer level in order to ensure maximum uptime and machine availability. This not only ensures that the technicians working on your equipment have undergone the appropriate training, but it’s also a good idea for a service manager to keep a “live” document or log of pertinent service information. This best-practice tip can save a lot of headaches and will keep a consistency within the department and relates to all aspects of the machine both big and small, from grease and engine/transmission service to major overhauls. Every service performed should be documented and logged for the records.
Many companies are mandating operator daily inspections or walk-arounds as a best practice. It does not have to be at a “technician’s level,” but to look for simple, obvious things that might hinder and affect the machine’s performance and tie in with maintenance or repair. Click here for pdf checklist.
It’s very important to develop a checklist of things to look for and have the operators go through each item, check it off, and hand in the completed checklist prior to operating the equipment.
It’s also important to note that not all wheel loaders are built the same. The design philosophy of a wheel loader varies from manufacturer to manufacturer. Some machines will need more repair and/or preventive maintenance than others.
What do I look for?
Before each shift, it is recommended that a daily walk-around on the wheel loader is conducted before operating the machine. If there are daily maintenance items or hourly servicing that need to be fulfilled such as greasing, oil change, etc., those need to be addressed before operating the loader. It is recommended the operator be aware or trained to look over a few points on the wheel loader before operating in order to ensure the safety of the operator and the others within the aggregates mine or quarry. A daily inspection list follows.
Daily inspection checklist:
Perform daily maintenance. Wheel loaders greasing points typically are associated with the boom, curling-linkage, steering, hydraulic cylinders, and center-hinge point. Centralized or automatic lube can save on time and maintenance.
Clean windows and mirrors. It sounds very simple and easy, but many operators do not keep their loaders, let alone their windows and mirrors, clean. It is very difficult, if not impossible, to operate the machine safely when these are dirty. Morning dew and bright sunlight will impair an operator’s ability to properly operate using the dirty mirrors when reversing. With clean mirrors and windows, other machines, people, and hazardous conditions on-site will be visible and hopefully be avoided. If a mirror is cracked or not visible, it is the operator’s job to report it to his superior in order to get the machine fixed as soon as possible for his or her own safety, the safety of others, and to avoid fines.
Check and wear your seatbelt. All operators need to check if their seatbelt is properly functioning. An operator needs to be fastened into his seat whenever he or she is operating to eliminate the chance of hitting his or her head on the roof and be knocked-out while still operating the machine.
Secondly, in case of an emergency, the seatbelt will ensure the operator is centrally located in a ROPS/FOPS (Rollover Protected Structure/Falling Object Protected Structure). Never jump out of a moving loader. Remain fastened into the seat at all times while operating the wheel loader.
Finally, if there are loose items in the cab, these items also need to be fastened. Many loaders are equipped with fire extinguishers or lunchboxes — these need to be fastened because they can move around in the cab and potentially cause injuries — or worse — to the operator in an emergency situation.
Maintain recommended tire pressures or adjust based on load and haul distances. Overinflation reduces ride comfort, increases vibrations, and reduces traction performance. Excessive tire pressures can induce high vibrations through the loader, which may lead to cracked welds and brackets and possibly other service problems. Secondly, the operator can visually inspect the tires. Look for and report larger cuts, imbedded metals or stone, odd wear, cracks in the sidewall, or any other unusual tire characteristics.
Look for leaks and loose parts while inspecting the machine. It is better to mistake early morning dew for hydraulic oil leak vs. not checking at all.
Adjust seat to proper comfort. Allow feet to reach full extension of pedals and the operator to sit erect and alert. Adjust the steering wheel as well.
Check control lamps when starting up the machine. Make sure the machine is checking itself and that there aren’t any error codes, warning lights, or audible alarms alerting the operator. If so, advise management of any service required or active service codes and alarms.
When climbing onto or off the machine, always face the loader. Use the “three-point stance,” meaning if you have two feet on the ladder, then one hand should be on it as well. If you have two hands on the ladder, then one foot should be on the ladder as well — and never, ever jump off the machine. Always climb down safely.
Check to see if both the front and rear lights work. When checking the rear lights, have the operator safely place the machine in reverse while stepping on the service brake to check if the reverse lights and reverse audible alarm are properly functioning.
Operate safely! Enough said.
Loader operator dos and don’ts
For inexperienced operators, learn technique, consistency, and control first — not speed! Short term, this will reduce accidents, risk, and wear on the machine. Again, get the “seat time” and experience and learn to become an “operator.” Speed and expertise will come with time. Here are some tips:
Control spillage. This will allow you to work on clean floors, reduce fatigue from road input, and maintain higher productivity through faster speeds and minimum cleanup.
Clean and maintain a fairly level floor in the loading area. This will allow easier, more consistent loading. This also minimizes cutting of tires in the loading area for loaders and haul trucks.
Maintain proper bucket capacity. If the loader is being operated correctly, you should be able to get respectable bucket capacity per material density. Forcing more into the bucket will probably end up with spinning tires, loss of production, and higher fuel consumption.
Load haul trucks to their payload capacity only. Do not overload. We do not want to repair or create additional maintenance on other machines!
If you have long distance travel, keep alert and adhere to site maximum speed.
If possible, have the bucket be slightly wider than the outside of both front tires to minimize damage and ensure longer tire life.
Keep the engine humming
To keep the engine on a wheel loader running smoothly and efficiently, follow these tips:
Check the engine oil levels daily either by dipstick or vehicle diagnostics (if equipped). Check the latest change interval to see if it is time for oil and filter change. Be sure you are using the manufacturer’s recommended oil for the specific machine and the proper viscosity range.
Injectors should be monitored through service diagnostics tools. Hard starting along with black exhaust smoke could indicate injectors failing or having an improper spray pattern.
Check fuel water separator for proper fuel level and drain bottom container. Be sure bottom bowl section has heater installed and plugged in to avoid freezing if equipped on machine.
Fuel filters must be checked and serviced per the manufacturer’s time intervals. Some machines require 500-hour interval changing due to engine compliance. Fuel fittings and “Banjo” fittings should be checked for possible ingress of air into the system. Usually “white smoke” could indicate air in the fuel lines in addition to water in fuel and cylinders.
Turbos and superchargers can be routinely reviewed for oil leakage and noise. Generally, low-boost pressure will lower machine performance under load and in addition to restricted air cleaner filters, could attribute to “black smoke.”
Fuel quality at the work site warrants a review. Bulk fuel tanks could have water ingression from improper breathers and/or fill caps. Proper use of fuel additives also is important.
Radiator cleaning is necessary for maximum cooling as well as coolant type and solution percentage. Checking the coolant level is a daily routine that should be performed. It is imperative that the correct type of coolant is used per the loader manufacturer’s specifications.
Essential electrical tips
Battery condition is vital for a loader to operate without starting and other electrical issues. The loader manufacturer designs cold cranking amps, reserve capacity, and battery size for proper starting and electrical load conditions. Replacing a battery with another type or size of battery will compromise the OEM design and electrical issues could occur, such as batteries draining during machine-off cycles, low starting current, and minimum system load requirements.
The batteries should be checked with a load tester rather than a simple voltage check. The battery electrolyte should be 10 mm (0.4 inch) over the plates in the battery. Top off with distilled water as needed. Keep dirt and debris off of batteries so they can vent properly and prevent voltage flashover. Also be sure the battery hold-downs are secure. In addition, battery cables and battery terminals are items that must be inspected to be sure that contact areas are free from corrosion and connections are tight. If a booster battery is required to start the engine, the instructions in the manufacturer’s operator’s manual must be strictly followed. If needed, charge the batteries with a battery charger. If the batteries do not take the charge, replace the batteries. Moreover, on a 24-volt system, never install a 12-volt option directly to one of the machine’s 12-volt batteries. This will allow the other battery to be overcharged by the alternator. Install the option to an approved 24-volt to 12-volt power converter. Finally, always turn the main battery disconnect switch off over the weekend.
Alternator output should be normally at 27.5 to 28.5 volts. Alternator, alternator belts, and terminals need to be inspected for maximum charging. Check that cable terminals and terminal studs are well cleaned and tightened every 500 hours. Always check belt tension every 250 hours. When replacing twin belts, be sure replacement belts are identical size and recheck tension after belt run-in period. Never disconnect the alternator leads while the engine is running or allow the alternator output socket to connect to the chassis, or reverse the power cables to the alternator. This could damage both the alternator and regulator. Starter ground cables must also be secure. Never connect jumper cables to the starter itself. When re-installing cables, multiple cables on starter terminals should be large diameter cables first then smaller sizes.
Wiring harnesses are the blood stream of the electrical system. They not only transport the current needed for components to function properly, today they are the devices that carry the digital information between computers onboard. These harnesses should be checked for proper routing and avoidance of sharp edges and heated surfaces. Their connectors, as well, have to be checked for fretting and possible corrosion. Most electrical problems are associated with unsecured negative grounds, so these are the first places to look at if multiple electrical circuits are affected.
Electrical components such as fuses, circuit breakers, relays, and computers all have to be checked periodically. When changing fuses and circuit breakers, always replace with the same type rating to avoid excessive current to circuit boards and wiring. Relays also need to be of the same size, capacity, and voltage. Be sure also that the specific relay is either continuous or intermittent duty concurring with the loader manufacturer’s design requirements. Also, when installing a two-way radio, mobile phone, etc., installation must be performed according to the manufacturer’s instructions in order to eliminate interference with electronic systems and components intended for the function of the machine. In addition, the computers onboard in today’s loaders have diagnostic capabilities to utilize in troubleshooting the root cause of electrical issues. It would be advantageous and cost prohibitive to utilize these diagnostic features in these computers to troubleshoot issues. Finally, before welding on the machine or on attachments, turn off the battery disconnect switch and unplug all connectors to onboard computers.
Machine work lights are essential for loader productivity and safety. These lights should be checked and replaced if needed to provide the operator with the best working conditions.
Maintaining hydraulics, steering, and brakes
Hydraulic and transmission oil and filters must be checked for proper level and condition. In doing sure, be sure to use the manufacturer’s recommended oil for the specific machine and the proper viscosity range.
Inspect the machine for hose rubs and potential leaks, making sure the fittings are properly tight for brakes, steering, and the hydraulic work circuits. Hydraulic pumps should be inspected for proper settings for specified pressure outputs. Cycle times of hydraulic boom, bucket, and steering all can be affected by too low of pump output.
Inspection of machine brakes and parking brake is vital for safe operation. Brake wear, accumulator pressure, and pump quality all play an important part to control loader-stopping parameters.
Other areas of concern
Tires should be examined for excessive wear and proper air pressure. Size and type are important for different applications and using different sizes on the same axle could lower driveline life and its internal components.
Greasing is essential for linkage points and pins on the loader especially the front frame and bucket. If the loader has an automatic greasing system, the grease reservoir needs to be checked daily to avoid air entering into grease circuits.
Other areas of concern to review are fire suppression systems, handrails and steps, loose hardware, cab windshield wipers and washers, and overall machine condition.
Cleanliness is a decisive factor for operational reliability of the machine’s systems. Therefore, keep the machine clean. Oil makes steps slippery and is also dangerous in combination with electrical systems or tools. Oily clothes or clothes drenched in grease constitute a serious fire hazard. Keep the machine especially clean when operating in environments with fire hazards, such as saw mills, transfer stations, etc. In such environments, suitable equipment to reduce the risk of accumulation of material and spontaneous combustion should be fitted (e.g muffler guard, radiator screen, heavy-duty pre-cleaner, etc.). Make certain that the windscreen, rear and side windows are kept clean in order to ensure proper visibility and adjust the mirrors accordingly.
Keep up to date with operator training manuals, service bulletins, service training courses, safety, and environmental issues. Perform a “walk-around” the machine to be sure nothing appears to be unsafe before operating or servicing machine. Always follow all instructions in the machine’s operator’s manual. Lastly, a safety-conscious person and a well-maintained machine make for a safe, effective, and profitable combination.
Michael Stec is a sales training specialist for compact road and GPPE products at Volvo Construction Equipment North America. Stec may be reached via phone at 828-65-2173 or via e-mail at firstname.lastname@example.org.