With easier handling and
more efficient storage in
their favour, square bales
for silage are growing in
popularity, and there is a
good supply of second-hand
balers for farmers who
cannot justify the cost of a
new one. Mervyn Bailey
checks out what to look for
when buying a square baler
with a bit of history behind it
OVERALL appearance and the condition of components prone to damage or wear should be the first considerations when looking over a used big square baler, according to Roger Haines.
As service engineer at New Holland dealer Oakes Bros, East Ilsley near Newbury, Berks, he knows these machines inside out, along with their strengths and weaknesses.
"For example, the condition of the groovers on the bale chamber floor are not only essential for producing a decent bale, they give a clue as to how well the machine has been looked after," he points out.
If the groovers are damaged or missing, it is a fair bet that some hefty foreign object has found its way into the bale chamber. Either way, they should have been replaced; the type of weld holding them in place gives a clue as to whether they are originals or replacements. Original groovers will be secured by a clean machine weld, replacements by more uneven hand welding.
"If the groovers are damaged, there will be a build up of trash which can be pushed into the knotters when the needles pass through the chamber," explains Mr Haines. "Better shaped guards around the stuffer transmission area on the more recent New Holland BB models allow rubbish to fall to the ground."
On pre-1996 New Holland models, shear bolts protecting the stuffer mechanism were inclined to give way all too often in wet conditions. Most of these balers have been retrofitted with a trip system instead, which can be identified by a spring and rod used for setting the flake density in the pre-charge chamber.
While in this area on the left-hand side of the baler, the condition of the knotter drive should be checked. This is a crown and pinion set-up on the D1010, but a gearbox on the BB range.
Dirt can build up on the crown and pinion, although the auto lube system should keep this mechanism clean when working. If the chain for the knotter drive crown is rusty, then it is clear that the auto lube is not working as it should.
"There should be about 3mm of backlash in the crown and pinion gears – any more and it needs adjusting," points out Mr Haines. "This is done by taking out some of the shims from behind the crown gear and tightening it up again."
These balers were not designed to cope with the fast road speeds of modern tractors, and when transported along rough roads, sharp shocks can crack the shaft going into the main gearbox. To overcome this, New Holland fitted a band brake to support the flywheel and cushion against such shocks. Tyres with excessive wear on the outer shoulder hint at high road mileage.
At least the main bale forming mechanism should be in good shape.
"The plunger ram bearing should not give any trouble as long as it has been kept well greased and I have yet to replace one," remarks Mr Haines. "The clutch and brake should be good for several thousand bales but should at least be checked annually, if not changed as a precaution against breakdowns."
Check for burn marks around the plunger brake, which indicates that the discs may not have been changed when worn out.
"When most people think of square balers they normally think of knotter problems," adds Mr Haines. "But there have been vast improvements in knotter design over the years and they rarely give serious problems these days."
Flags on top of the baler tell the operator that the knotters are working properly – they go down when the bale is being tied and pop up again when the knotters have completed their task. So it is important to make sure these are all in place ready to indicate any problems.
Regular maintenance goes a long way to reducing knotter problems. For example, it is worth changing the retaining spring every season so that the string is always held in place for the knotter. The jaw hooks, which turn the string to create a knot, should all be present and correct; if they are not in view, check whether the pin for the retaining spring has broken.
Similarly, check that the toothed bar that regulates bale length has a full set of teeth, otherwise bale size will be inconsistent.
"If fans are fitted above the knotters this is a bonus as they will help keep the knotter mechanism clear of debris," emphasises Mr Haines. "It is not a perfect solution but it is a 90% cure and on more recent balers the fans are more efficient."
Other extras worth having are a chopping unit, although the initial cost means there are not many machines about so equipped. Likewise, a hydraulic bale ejection system, which apart from removing the last bale of each field, makes it a lot easier to tackle problems with the groovers or the needles than when the chamber has to be emptied by hand.
As with any baler, the pick-up needs to be in good condition, so run through the standard checks for cams and track condition, and missing tines. The windrow guard is a crucial part of the pick-up as it helps produce an even flow of material into the chamber.
On pre-1996 New Holland models, the windrow guard fingers were made of quite light material and tend to break off. Tougher steel was used on later models to help keep them in place. *
Left: Overall appearance of the baler will give a good indication of its
work-load and how well it has been looked after.
All panels on this 1995 model are
in good shape.
Below: Cracked lugs and excessive wear
on the shoulder of
the balers tyre indicate heavy
Above: Check the pick-up for excessive wear and signs of damage – it needs to be in good condition. The windrow guard fingers on pre-1996 New Holland models were made of light steel and tended to snap off; later versions use heavier material.
Below: Raising the knotter out of work shows the condition of the cutting knife and the jaw hooks that turn the string a full rotation to create a knot.
Above: Early New Holland balers suffered excessive breakages of the shear pins protecting the stuffer mechanism. This machine, like many of its age, has the retro-fit trip arrangement. The crown gear wheel can also be seen, with the knotter drive shaft engaging it at an angle. The condition of the drive train indicates whether the auto lube system has been working properly.
Left: The groovers positioned on the bale chamber floor are critical to the functioning of the needles and knotters. If missing or damaged, the needles can push built up trash into the knotting mechanism. The "hay dogs" on the side and top of the chamber prevent the flake collapsing on the needles when the plunger retreats.
Below: The stuffer forks and
pre-charge chamber should be in good condition with no dents or obvious signs of excessive wear.