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Buyer's guide: McHale 998 square bale wrapper

Initially launched in 1998, McHale’s 998 square bale wrapper has secured itself as a favourite of contractors and farmers alike, when making silage with square bales. Alex Heath sought expert advice on what to look out for when considering a used example.


Although the original design of McHale’s 998 square bale wrapper has changed little in its 22 years of production, some improvements have been made throughout the years, with the addition in 2018 of the 998 High Speed model.


Headstock and pump

Headstock and pump

The McHale 998 comes as standard with a fully integrated pto driven, load-sensing hydraulic system with a maximum output of 60 litres/min at 165 bar, while the oil reservoir is 130 litres. This allows it to be operated using lower horsepower tractors from 80hp.


Run the pto pump at 700rpm until the oil is warm, then inspect the pump for any external oil leaks. It is recommended that both the return filter and the suction filter on the hydraulic tank is changed. This should be done before the start of each season. If necessary, the hydraulic oil level should be topped up also.

Inspect the linkage pivot pin that attaches the headstock to the tractor for wear. If wear is excessive, the bush may need replacing.


Intake conveyor

Intake conveyor

Used prices

  • 998 Standard, 2002, 60,000 bale count: £13,000 + VAT
  • 998 Standard, 2018, 22,000 bale count: £24,000 + VAT
  • 998 Standard, 2014, 40,000 bale count: £19,000 + VAT
  • 998 Standard, 2004, 70,000 bale count: £13,500 + VAT
  • 998 Standard, 2008, 36,000 bale count: £16,500 + VAT

Lifting the bale off the floor is the front conveyor. Ensure that all conveyor chains are present and correct – these may need adjusting if they are slack. Check the tension of the chains and adjust if they are slack.


There are two trigger arms fitted on the conveyor to detect the bale. Ensure these are present, in good working condition and that they do not foul when pivoting forward and back as they control the sequence of the wrapping cycle safely. Check the tension springs, fitted to the trigger arms, are present and positioned correctly.


As the bale moves to and from the wrapping position, it is transferred using the slat conveyor. Check to ensure all slats are fitted on the conveyor and that they are not bent or damaged. A damaged conveyor slat will foul a wrapped bale once lowered down on the conveyor after it has been wrapped.


Bale positioning

Bale positioning

During the wrapping process, the bale is supported using four rollers. Inspect these rollers for any scuffs or damage. If a roller is scuffed or damaged, this will cause a tear in the bale wrap as the film is being applied.


Remove the chain guarding and inspect the condition of the chains used to turn the rollers. These may require adjustment to ensure tension.


Potentiometers control the wrapping angle of the bale and are connected using slotted arms. Inspect these slotted arms and ensure they are straight. Any bend or kink in these arms will foul the potentiometer and place the wrapped bale down on the conveyor incorrectly. This can lead to the plastic getting damaged while the bale is being ejected from the conveyor.


When looking at the potentiometers, ensure the wiring for both raising the height of the bale and adjusting the angle of the bale are in good operational order and no damage to the wire is present.


Wrap dispensers

Wrap dispensers

The wrapping of the bale is carried out using two, 750mm dispensers. Check and ensure that both tension springs on each dispenser are not worn or have lost their tension. If damaged or worn, these will need replacing.


Next, check to ensure that both dispenser bobbins are in-line vertically, if they appear to be out of line then spiral binding will occur on the roll of film as it is being applied.


While inspecting the dispensers, look at the drive gears on the aluminium dispensers. The drive gears on the dispensers should be able to rotate – some grease may help.


Check to make sure the magnet on the film break sensors are present. If the magnet is not present this will lead to incorrect operation of the film break sensors. Ensure that both film break sensors are working, and the battery has not failed. The manufacturer recommends that these be changed every 30,000 bales to ensure correct operation.


All 998 machines are fitted with safety trip arms that are equipped with yellow flags. Check that these are present on the machine and inspect the condition of both the trip arms and safety flags. Fit new flags if the original flags have been damaged or discarded to avoid defeating this safety feature.




Common part prices

  • Main Conveyor: £549
  • Joiner link: £10
  • Conveyor slat: £11
  • Front conveyor pick-up chains: £115
  • Dispenser tension spring: £21
  • Conveyor trigger spring: £6
  • Film break caps: £124
  • Read sensor: £78
  • Potentiometer: £143

All dispensers on these machines come fitted with a hydraulic cut and hold. Check and adjust the bearings on the cut and hold slider rails, if needed. The blade used to cut the film should be inspected and replaced if damaged or blunt. Ensure safety is taken when carrying out this procedure.


After wrapping, the bale is delivered off the conveyor onto the ground through heavy duty rollers. Check the operational condition of the bearing on the rear of the conveyor and ensure that the rear conveyor rollers are turning smoothly by hand. These are designed to rotate freely and should not feel coarse while rotating.


Wrapping motor and arch

Wrapping motor and arch

The wrapping dispenser and motor are supported from the main arch. Ensure all bolts that connect the top arch with the main arch are secure and tight.


From there, it is important to check the wrapping dispenser motor and the gearbox, which are positioned on the top of the machine. Check the condition of the motor and gearbox. Ensure all bolts are tight and there are no oil leakages externally.


Finally, carry out an overall inspection of the machine. This should incorporate an inspection of the valve chest on the machine and ensure there are no major oil leaks from the main valve chest or adjacent smaller valves.


Check the condition of all hoses to ensure they have not perished, preventing downtime during the season.


Inspect the control console and its leads and connections. Ensure the unit is powering up and all functions are working correctly on the console. From here, the total bale count can also be found.

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