Getting your tanker ready for action
A well maintained machine is essential for making the most of the slurry season, writes Derek Casey
Slurry spreading season reopens this week in most counties, with the exception of those in Zone C, who must wait until the end of January before they are allowed to get slurry out.
In the meantime, there is now an opportunity to get your slurry tanker ready for the workload ahead.
A properly maintained tanker is essential for getting the optimum benefit from your slurry. Regardless of the spreading system used - splash plate, trailing shoe or injection - there are a number of things you can check on your tanker before the season kicks off.
Begin at the drawbar and work your way back with a thorough clean and power wash as this will allow you to see any defects in the body.
Staying at the front, check for wear on the drawbar which is inevitable due to heavy loads. Wear is also possible at the pivot, particularly if it hasn't been greased in a while.
Make it your New Year's resolution to replace any damaged guards on the farm with brand new safer units. Check the PTO guard for any wear and tear. Guard safety is hugely important on tankers because operators are often in close proximity to the drive shaft during tank filling. End-of-year statistics from the Health and Safety Authority show that most PTO-related accidents happen when limbs and loose clothing, such as overalls or jumper sleeves, become entangled in an uncovered spinning shaft.
Staying on the PTO, with the tractor turned off and the key in your pocket, wriggle the PTO joints and knuckles on the drive shaft. If there is any movement, change worn items before they self-destruct during the busy spreading season.
Check that the shaft can slide in and out without sticking; if it binds under power, it can't telescope as the tanker crosses bumps and dips, so high forces are fed into the pump gearbox and tractor, potentially causing extensive damage.
Replace a binding shaft if separation, cleaning and re-greasing doesn't manage to free it up. Check the pump input shaft as well - in particular, look for oil leaks where it leaves the casing.
Check the pump gearbox. The main areas are the filler plug, drain plug and level plug. Remove the level plug and some clean oil should be allowed to dribble out. If no oil appears, then top it up with some SAE 90 gear oil.
If you notice that the oil is milky, this means it is contaminated with water. Drain the oil and replace with new oil. Be careful not to overfill the gearbox as the seals may blow. On some pumps, a saddle tank holds lube for the pump's internal rotor vanes. Clean the area around the dipstick before pulling it out to prevent dirt dropping into the reservoir. Top up to the dipstick mark with fresh vacuum pump oil (not gear oil). Keep the tank as full as possible as this helps to cool the pump.
The oil dropper should drop oil at a rate of about one drop every two seconds - anything less and you risk the pump vanes seizing up. Oil lubricates the vacuum pump vanes and diverter and then leaves through the exhaust.
Have a look and clean off the clock pressure gauge. The clock usually shows tank pressure on one side and the tank vacuum on the other. If the hand doesn't return to zero, then replace it with a new one.
Also check the sight glasses; if they have turned cloudy, brittle or are hard to remove, they might need replacing as well. These gauges are important to let you know if the tanker is performing properly so they should be kept clean at all times.
If your tanker is a trailing shoe model and is fitted with a macerator, be careful to only carry out maintenance and repair work with the key removed from the tractor and PTO switched off. The inflow and drain hoses of the hydraulic motor should be depressurised; this will help relieve a build-up of back pressure from the slurry when opening the macerator. Check and empty the stone trap regularly for solid items. If removing or replacing worn or leaking slurry outlet hoses from the macerator, ensure they are fitted back on to the same outlets.
All greasing points should be greased weekly or every 50 working hours. It is critical to lubricate a macerator before use, but it is equally important to grease the macerator if it is not going to be used for an extended period of time (failure to do so could result in the macerator's components seizing up).
Gate valves on the slurry tanker control the flow of slurry into and out of the tank. Common problems are leakages or worn edges.
Check the slide's leading edge as it can be chipped or worn by stones, preventing an effective seal. Undo the operating rod's gland nut and take out the O-ring seal - if this is broken then air or slurry will leak past it and performance suffers. These parts can be replaced easily and are not expensive, but they make a big difference to performance.
The exit valve is normally held closed by a spring return ram or gas cylinder and opened hydraulically. A worn or damaged slide, a broken spring or a failing return cylinder could mean a big mess on the road, so these parts need regular inspection. Oil leaks at this point typically point to dodgy ram seals.
Brakes and tyres
Tyres need to be in good condition especially if you are doing a lot of road work. Inflate the tyres to the tanker manufacturer's recommended figure and remember to check and clean the lights on the tanker regularly.
Commercial axle brakes found on a lot of slurry tankers are easy enough to adjust. Jack the wheel so it's just clear of the ground, supporting the axle on stands if necessary.
Then move the adjuster until the brake locks the wheel. Back off the adjustment until the wheel just turns freely; repeat for the remaining wheels.
For the handbrake, check that it moves easily and that its ratchet works. Check that the handbrake is fully applied well before the lever reaches the end of its travel. If that is not the case, shorten the cable until it is - then see that the wheels still turn freely with the handbrake off.
Finally, when the wheel is jacked it's a good opportunity to check wheel bearings as well. When the weight is off the wheel, move it back and forth. A little movement is ok but if there is a lot of movement, the bearings need to be adjusted.
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