In wet weather, run a wheel loader slowly with the bucket low, stop the tyres spinning before they dig in, and keep off slopes and soft edges. Before the rain, check the tyre tread and pressure. After working in water or mud, wash the loader and grease every pivot point. Most bogged loaders and wet-weather breakdowns come from pushing on when the ground has already turned to mud.
Prepare a wheel loader before the rain
A wheel loader's tyres decide how it copes with mud, so check them before the wet arrives. Loader tyres carry a code on the sidewall: L-2 is a traction tread for soft ground and L-3 is the general-purpose tread most loaders run. L-4 and L-5 are deep rock treads made for wear and cut resistance, not for soft mud, so most wet farms and yards are better served by L-2 or L-3.
Check tyre pressure cold, as part of the daily walk-around, and set it to the figure in the loader or tyre maker's guide. Never let air out of a hot tyre, and don't drop pressure for mud on your own: ask your tyre supplier for a figure that suits your machine, load and ground.
Walk around the rest of the machine too. Make sure the axle, transmission and hydraulic tank breathers are clean and fitted, the lights and wipers work, and the cab seals keep water out. Plan routes on the firmest ground you have, and lay gravel or matting at the spots that always bog.
Working a wheel loader in mud
Working a wheel loader in mud comes down to speed and traction. Enter a pile in first gear at a steady speed, with the bucket flat. As the bucket bites, lift and curl together, which pushes the front tyres down and gives them more grip.
Ease off the throttle the moment the tyres start to slip. Spinning tyres dig ruts, wear tread fast and bog the machine deeper. If your loader has a diff lock, engage it before the wheels start spinning and use it in a straight line. Switch it off before you turn, and follow the operator's manual for your model.
Carry loads with the bucket about 20-30 cm above the ground, so the loader stays stable and you can see where you're going. On rutted ground, slow down further, because the bucket bounces and spills more when the machine pitches.
Slopes, soft edges and rollover risk
Wet slopes are where wheel loaders roll. Drive straight up and down a slope with the bucket low, and never turn or travel across it. Keep well away from the soft edges of dams, channels, creek banks and fresh fill, which can give way under the weight of the machine.
Always wear the seatbelt. A ROPS only protects the operator who stays in the seat, and Australian WHS law requires businesses to control the risk of rollover for earthmoving machinery.
Black soil and clay country
Black soil is the hardest ground to work in the wet. These cracking clay soils, called Vertosols, hold 35% or more clay, shrink and crack when dry and turn into sticky, low-strength mud when wet. They are Queensland's most common soil, across the Darling Downs, the Central Highlands and the Brigalow country, and NSW has large areas on the Liverpool Plains.
On black soil, wet mud clogs tyre treads and buckets within minutes, and traction disappears. If the tyres are packing solid and the loader is sliding rather than driving, stop and wait for the ground to firm up. Buyers in that country can find more on wet-season set-up in the Queensland wheel loader buyer's guide.
Getting a bogged wheel loader out safely
When a wheel loader stops moving forward, stop spinning the tyres. Spinning only digs deeper. Some operators use the bucket to lift and push the machine back a short distance, but that loads the linkage and frame. If a try or two doesn't free it, call for a recovery machine.
A recovery pull is one of the most dangerous jobs on a wet site:
- Attach only to tow points the manufacturer designed for towing, never to the bucket or lift arms
- Use a rope or bar rated well above the bogged machine's weight, and a recovery machine heavier than the bogged one
- Keep the pull within about 30 degrees of straight
- Put a damper such as a weighted blanket, mat or old tyre over the line
- Keep everyone clear of the line while it is under load
- Never join snatch straps with steel shackles, which can fly off like a bullet if something lets go
Storms and overhead powerlines
Overhead powerlines are a bigger risk in wet weather, because rain makes arcing more likely and storms can bring lines down. In Queensland, keep every part of the loader at least 3 m from powerlines up to 132 kV, 6 m up to 330 kV and 8 m above that. The network operator can set other distances. The WorkSafe Queensland exclusion zones set out the details, and other states have their own rules.
Use a safety observer whenever a raised bucket could reach the exclusion zone. Treat every fallen line as live, and stop work during lightning.
Looking after a wheel loader after the wet
A wheel loader that worked in water or mud needs attention before the next shift. Shut the engine down and apply the park brake, then wash mud off the radiator and oil cooler cores, the belly guards, the articulation area and the axles. Don't blast high-pressure water straight at wiring connectors, sensors or seals, and dry the connectors after washing.
Grease every pivot pin, the articulation joint and the steering cylinder pins more often than the dry-weather schedule, until fresh grease shows at the joint. Wipe off the excess so it doesn't hold grit. Never let water rise above the bottom of the axle housings.
Wet brakes grab less. After driving through water or in rain, slow down and press the brake pedal gently a few times to dry the brakes, then test them on firm, level ground. If the hydraulic or axle oil looks cloudy or milky, or the loader has worked in water, send an oil sample to a lab before the water wears the pumps.
Wet, muddy work calls for more frequent greasing and cleaning, so tighten your wheel loader maintenance routine through the season. For longer wet spells, park the loader under cover, or on hard, dry ground with a cover, and keep the battery terminals clean and tight.
Cleaning a wheel loader between sites
Mud on a wheel loader can carry pests and weeds from one property to the next. In Queensland's fire ant biosecurity zones, a loader must be cleaned free of soil and organic matter before it leaves a site. Machinery moving from the infested area into NSW needs a Plant Health Certificate showing it was cleaned and checked.
Everywhere else, clean mud and weed seed off the wheels, bucket and belly plates before moving between properties. Don't track mud onto public roads: use a gravel exit, rumble grid or wash bay, and wash down where silt can't run into drains or creeks.
Choosing a wheel loader for wet sites
For wet farms and yards, a compact loader with the right tyres often does more than a heavy one, because it sinks less and is easier to recover. DJJ sells and hires LGMA wheel loaders from 3.8 t to 8.2 t at Silverwater, Meadowbrook and Bayswater. Call 1800 355 388 with the work and the ground you deal with.
