Farm Ireland

Saturday 21 October 2017

Tanker efficiency key to maximising slurry benefits

As the spreading season kicks off around the country, Derek Casey looks at key tips for tanker maintenance so that farmers can make most of the valuable nutrients found in slurry

Regardless of whether you are using your own equipment or hiring someone in to do the job for you, a properly maintained tanker is essential for getting the optimum value from slurry
Regardless of whether you are using your own equipment or hiring someone in to do the job for you, a properly maintained tanker is essential for getting the optimum value from slurry
CAPACITY: Ground conditions are not up to supporting the weight of tankers in many parts of the country, but slatted tanks are full to capacity at this stage
Derek Casey

Derek Casey

With so much rain in recent weeks, slatted tanks are at full capacity on many farms. The pressure is now on to get some slurry out, but ground conditions are just not up to it in a lot of cases.

Contractors I spoke to this week are reporting brisk demand, with phone calls from farmers looking to get slurry out once ground conditions improve. In other cases many farmers are using their own tankers to get slurry out.

Regardless of whether you are using your own equipment or hiring someone in to do the job for you, a properly maintained and serviced tanker is essential for getting the optimum benefit from your slurry.

It is a valuable nutrient source on the farm, but it is only as good as the spreading system that delivers it. It has to be used wisely to give the best results in terms of early grass growth, and key to this is how well the slurry tanker is spreading.

There are a number of things you can do to your slurry tanker before you start. The aim is to ensure it is spreading correctly and that your grass is getting the best nutrient boost possible from the slurry.

Before you start, wash the tanker. It sounds quite simple, but begin at the drawbar and work backwards as this will allow you to better see any defects in the body.


Wear on the drawbar is inevitable so be sure to pay close attention to this area. Wear is also possible at the pivot, particularly if it hasn't been greased in a while.

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As ever, be sure to check the PTO guard for any wear and tear. Guard safety is hugely important on tankers because on all but the newest models the operator still dismounts the tractor during filling.

Statistics from the Health and Safety Authority show that the greatest number of PTO-related accidents happen due to loose clothes becoming entangled in an uncovered or spinning shaft.

Staying on the PTO shaft, with the tractor turned fully off, wriggle the PTO joints and knuckles. If there is any movement, change worn items before they self-destruct during the 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 risks seizing up the pump vanes. 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.

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 aren't 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.


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, and support 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 and 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.

Irish Independent