How to service your tanker

With the slurry season finally in full swing in some areas, farmers and contractors are taking advantage of the unusually mild weather and good ground conditions to relieve strained slurry storage facilities.

This time of year is commonly busy in the second hand tanker market as many people are looking to change or upgrade their tankers for larger, newer versions in order to get through their work more efficiently.

When looking at any used vacuum tanker, be it your own or one you wish to purchase, there are some key points to pay close attention to in order to avoid potential breakdowns and associated costs down the line.

The same principles apply to all brands and sizes of tankers and should be used to check over your tanker before commencing work this season.

Over time and excessive use the hitch will wear from the friction between it and the tractors pick up hitch, this can be reduced by regularly applying grease to reduce the friction but cannot be avoided. When looking at any used machine pay attention to the hitch as this is a major safety concern if worn, as it is in many cases the only link between the tractor and tanker.

Worn hitches should be immediately replaced by an approved dealer or repairer.

As always, PTO safety is vital on any machine and even more so on tankers, due to the fact that the operator works in close proximity to it changing between pump and discharge.

According to the Health and Safety Authority, the greatest number of PTO related accidents are because of loose clothing becoming wrapped around an uncovered or spinning shaft.

It is critical that the safety guard is fitted to the complete shaft and is undamaged. The shaft should also be inspected in relation to mechanical condition by moving the universal joints and knuckles checking for resistance and play.

Worn components will need to be replaced to avoid breakdowns and downtime.

Check that the shaft can slide in and out without sticking; if it binds this may indicate that it is slightly bent. If it cannot expand under power when the tanker crosses rough ground, high forces can be transferred into the pump gearbox and tractor, potentially causing damage.

Replace a binding shaft if separation, cleaning and re-greasing doesn’t manage to free it up. Also check that all grease nipples are in place and not blocked.

The main working component on any tanker is the vacuum pump itself, which removes the air out of the tanker creating a vacuum which in turn sucks up the slurry.

It also works the opposite way by pumping air back into the tank creating pressure to discharge the slurry. At the front of the pump a small gearbox transfers the drive from the PTO into the pump. The oil in this gearbox should be checked regularly to make sure that it is to the correct level and good quality.

If no oil appears, it should be topped up to the relevant mark with SAE 90 gear oil. If you notice that the oil is milky, it is contaminated with water and should be replaced with new oil.

Be careful not to overfill the gearbox, as this may cause the seals to blow or leak. The front seal where the stub shaft comes out should be closely examined that it is not cracked, worn or leaking. The bearings in the gearbox can be checked by moving the stub shaft up and down checking for movement.

Excessive play may indicate a problem with the gears or bearings and should be investigated further. Try to rotate the pump by hand with the PTO shaft turned at 90 degrees for leverage.

This will give you a good indication of the vane and overall pump condition before applying power to it from the tractor.

At this stage it is a good idea to fit a tractor to the tanker in order to run the pump. With the pump running, check that the oiler is working correctly.

The oil delivered from the oiler lubricates the vacuum pump vanes and diverter before leaving through the exhaust. As a rule of thumb at least one drop should be clearly visible every two seconds.

If the oiler is not working correctly, it may be due to dirty oil or blocked pipes, worst case scenario the oiler pump itself may be faulty.

Some pumps are fitted with a header tank for feeding the oilers. Before checking the oil level, clean the area around the dipstick before pulling it out to prevent dirt dropping in.

Top up if necessary to the mark with fresh vacuum pump oil, never use gear oil.

Check all pipes on the tanker for their general condition. Rubber will weaken and crack over time and should be closely inspected for problems. Worn or cracked pipes should be replaced.

These should be cleaned regularly as they can build up with silt over time depending on the type of liquid the tanker is working with.

If the trap becomes full of dirt it may stop the diverter ball returning fully to create a seal which may cause contamination getting into the pump. The silt trap is normally made of a hard clear plastic and can become cloudy or crack over time and will need to be replaced.

Pressure gauges are important as they let you know if the tanker is performing properly. They should be kept clean and operational at all times.

The pressure gauge usually shows tank pressure on one side and the tank vacuum on the other. If the hand doesn’t return to zero, then there is a problem with the gauges accuracy and it should be replaced.

For safety all tankers are fitted with at least one pressure relief valve which will open if the pressure or vacuum becomes too much.

The tanker will need to be running in order to check the pressure relief valve, which is done by pushing or pulling the end. Faulty valves should be replaced immediately as they are an important safety feature.

Most tankers are fitted with at least one sight glass to give the operator an idea of the level of liquid inside the tank. These sight glasses can become brittle over time and turn cloudy obscuring visibility. If this occurs they will need to be replaced.

Tankers can be supplied with numerous gate valves in different locations. Gate valves control the flow of slurry in and out of the tank and are subject to wear and tear.

A common problem is leakages due to worn edges. Worn edges will prevent an effective seal being achieved which will affect the tankers performance.

To replace the seal, undo the operating rod’s gland nut and take out the seal. If it is broken, then air or slurry will leak past it affecting performance. Replacing the seal is inexpensive, but will make a big difference to performance.

At the rear of the tanker an exit valve is fitted which is held closed by a spring return ram or gas cylinder and is opened hydraulically to discharge the slurry.

If the exit valve becomes faulty due to a worn or damaged slide, a broken spring or a faulty hydraulic cylinder, it could lead a big mess on the road and a major headache.

It is vital that these parts are regularly inspected. Oil leaks typically mean that the ram seals are becoming faulty and should be replaced.

Check over the complete tanker in relation to its structural condition. Pay close attention to structural points where the barrel meets the chassis, as these would be subject to increased stress and can crack.

Any dents or welds may weaken the barrel and potentially cause it to implode. Inspect any repairs previously carried out, making sure they were carried out correctly and not hiding any further issues. The best place to inspect the tanker is underneath the barrel at the rear.

It is at this point that all the slurry passes internally to the exit valve and will therefore wear more than other places.

All rear lights must be operational and in good condition for safety before the tanker can be taken out on the public road. It is good practice to keep the lights working correctly regardless of whether you are on farm or the road.

All hydraulic pipes should be checked over for general condition paying particular attention for wear and cracks, which may burst during operation leading to downtime, fluid loss and possible environmental contamination.

Damaged pipes should be replaced before commencing work.

As there is no weight regulation on slurry tankers the tyres can be subjected to heavy weights affecting their structural strength, especially when travelling at high speeds.

Take time to check over the complete tyre, paying close attention to cracks or previous repairs that have been carried out. Tyres are what connects the tanker to the road and can lead to a serious accident if they blow out while driving.

New tyres can be a substantial cost and therefore should be checked over regularly especially before committing to buying a used tanker.

Most modern tankers are fitted with commercial axles which are relatively easy to adjust the brakes on. Firstly, jack the wheel so that it’s clear off the ground and support the axle on stands for safety. Next, adjust the brake push rod until the wheel locks.

Back off the adjustment slightly, until the wheel just turns freely and repeat for the remaining wheels. In relation to the parking brake, firstly check that it moves freely and that the ratchet mechanism works.

If it is seized from dirt, then it will need to be freed up with oil before it can be adjusted.

To adjust it, check that the parking brake is fully engaged before the lever reaches the end of its travel. If that is not the case, shorten the cable until it is and then check that the wheels turn freely with the parking brake is off.

While the wheel is off the ground, it is a good opportunity to check the wheel bearings. This is achieved by rocking the wheel to and fro. If there is lateral movement, it may indicate a wheel bearing problem and should be investigated further.

While working at the wheel, check the studs making sure that they are all in place, tightened regularly and not cross threaded.

Put on the overalls and climb in under the tanker. Check the hinge points that attach the sprung drawbar to the chassis.

This pin can be subject to wear if not greased regularly, so it’s important that the grease nipple is working and the pin and bushings are not worn. Replacing these is a big enough job and should only be carried out only by an authorised dealer or repairer.

While underneath, check the drawbar suspension as well as axle suspension system where fitted. Check that the springs are in good condition and all U bolts are tight and in place. Any worn suspension components should be replaced.

There are some examples of clean second hand tankers available on the Irish market through the dealer network at realistic prices, which may be a viable option for someone looking to update their tanker without going as far as a new version.

Some examples include:

By following these few key points you should be able to find yourself a good value quality tank that will allow you to increase your efficiency and have a more profitable and safer slurry season.

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