Farm Ireland

Friday 19 October 2018

5 tips to prime your pumps and tankers for the busy slurry season

Spring spreading is by far and away the best way to make your slurry count.

Spring application can deliver over three times more nitrogen per ha than summer spreading.
Spring application can deliver over three times more nitrogen per ha than summer spreading.
Derek Casey

Derek Casey

Regardless of what zone you are in, there is an opportunity to get tankers ready for the forthcoming glut of work.

Spring spreading is by far and away the best way to make your slurry count.

Teagasc research has shown that 3,000 gallons per acre spread in spring will supply about 60 units of nitrogen per hectare - this compares to 13 units per hectare if the slurry is spread in the summer or autumn.

But spring spreading can only be done if your machinery is ready to roll when the opportunity arises. In most counties, the pressure is already on to get some slurry out, but ground conditions will need to be assessed on an individual basis.

Remember that heavy tankers will do more harm than good in soft conditions. If you have the storage space you are better off waiting for things to firm up a bit more. Contractors I spoke to this week reported brisk demand, with calls from farmers booking their services as soon as weather permits. In other cases farmers are using their own tankers to get the job done.

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

Wheel nuts and bearings should be checked daily during heavy use.
Wheel nuts and bearings should be checked daily during heavy use.

It is a valuable nutrient source on the farm, but it is only as good as the spreading system that delivers it.

Slurry has to be used well to yield the best results for early grass growth, and key to this is how well the slurry tanker is spreading.

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Here are some suggested maintenance tips to get the most from your spreader.


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

Wear on the draw bar is inevitable from lugging about heavy loads, so pay close attention to this area. Wear is also possible at the pivot, particularly if it hasn't been greased in a while.

A properly maintained tanker is essential for getting the optimum value from slurry this spring.
A properly maintained tanker is essential for getting the optimum value from slurry this spring.

PTO shaft

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.

We were all shocked at the 30 farm deaths recorded in 2014 and sensible steps must be taken to mimimise the carnage this year.

Information from the Health and Safety Authority shows that a large amount of PTO-related accidents happen due to loose clothing becoming entangled in an uncovered or spinning shaft.

Staying on the PTO shaft - with the tractor obviously turned fully off, wriggle the PTO joints and knuckles.

If there is any movement change worn items before they self-destruct during the spreading season. Check that the shaft can slide in and out without sticking.

If the shaft binds under power it won't be able to 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 - here you are looking for oil leaks where the shaft leaves the pump casing.


Check the pump gearbox. The main areas to look out for here are the filler plug, drain plug and the level plug. Remove the level plug and allow some clean oil to dribble out.

If no oil appears top it up with some SAE 90 gear oil. If you notice that the oil is milky, this means it is probably contaminated with water.

The answer here is to drain the oil and replace with fresh new oil. A word of warning; always read the oil level on the level plug carefully because overfilling the gearbox can lead to the pump's seals blowing out.

On some pumps a saddle tank holds lubrication oil 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 the diverter before leaving through the exhaust.

Clean off the clock pressure gauge and have a look to see that it works properly. Note that the clock usually shows tank pressure on one side and the tank vacuum on the other.

If the hand doesn't return to zero, 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 and checked regularly.

Gate valves

Gate valves on the slurry tanker control the flow of slurry into and out of the tank.

Due to the high pressures they deal with, common problems here are leakages or worn edges.

Check the slide's leading edge as it can be chipped or worn by stones, preventing an effective seal and causing slurry to pour out during road and field transit.

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 while they aren't expensive they can 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, as many contractors do.

Inflate the tyres to the tanker manufacturer's recommended figure and remember to check and clean the lights on the tanker regularly.

Broken indicator lights at this time of year are responsible for many road accidents as impatient road users attempt to overtake slowly moving tractors and tankers.

Are you're brakes up to the job? Commercial axle brakes found on a lot of slurry tankers are easy enough to adjust. Jack the wheel so that it's just clear of the ground, supporting the axle on stands to maintain safety at all times.

Then move the adjuster until the brake locks the wheel. Finally, 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 completely freely with the handbrake off. 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.

Once you get up and running it is useful to keep an eye on all of the things mentioned at regular intervals. During busy periods, daily checks should be made on the most important parts.

These include the gearbox for oil level, the wheel nuts and bearings, the pressure gauge, the PTO shaft and the the rear gate valve.

Weekly checks are adequate for the vacuum pump oil level, while the gearbox oil should be changed after each 300 hours of work done by the tanker.

Finally, in the midst of all the tanker prep it is easy to overlook the agitator.

This should be in good working order with a completely covered PTO shaft.


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