Sands Agricultural Machinery is one member of a big gaggle of British-based self-propelled sprayer manufacturers.

The unmistakeable Satsuma livery of the Norfolk-built machines has been treading the UK’s tramlines since Neal Sands started the company almost 40 years ago.

Early models were built on a high-clearance David Brown tractor and were a far cry from the Deutz-propelled machines of today.

But alongside the 50-odd new machines bolted together each year, the team of fitters also refurbishes second-hand models.

We joined service manager Shane Trenton to work through a 58-plate SLC 4000. With 4,155 hours on the clock the sprayer was closing in on the milestone 5,000-hour mark, so we’ve picked a few of the potential troublespots to look out for.

Any sprayer will want the cab filter replaced annually at least (more frequently for spud sprayers). Hoist up the cab roof to get to the filter 
– it’s just a case of unclipping the old one and slotting in the £134 replacement.

1. Tyres are an expensive, but necessary, inconvenience. Don’t let them wear much below 50%. Sands recommends sourcing new ones from Mitas or Michelin – a new set of 380/85 R30 boots will cost £1,600.

   

2. By the time it reaches the 3,000-hour mark there’s a good chance the running gear will look and feel worn. Check the axle keyte, track rods and bump stop every 1,500 hours – the lot can be replaced in eight to 10 hours – and keep them well-greased in the meantime.
3. A knocking noise while on the move could signal a worn keyte. Replacement takes about three hours depending on pin seizure. Jack up the machine, take both wheels off, then pull the front tripod down and feel for slop in the ball joint. If there’s play remove the nyloc nuts from either side of the pin and tap it out. A replacement assembly costs £137, including the two nuts. Once the new one is in place fit a new pair of washers either side and pinch the nuts tight to close the clevis.
4. Front and rear bump stops provide a comfortable buffer for the sprayer to sit on when it’s parked up. These can begin to split if they’ve been subject to varying temperatures or accidentally scored by something sharp. Unwind an 8mm thread to free the rubber stop – a replacement costs £58.
5. Track rods are a classic troublespot, so check for any slop just like you would with any other vehicle. If you can easily shunt it to and fro then it’ll want replacing. Start by loosening the 30mm nut and knocking the ball joint out. The replacement comes as a complete threaded item, so just wind it back in and re-track. Be sure to buy the ball joints with a grease nipple fitted – earlier versions didn’t have this and it should extend service life. A set of eight steering joints for the front and rear axles will set you back £550.
6. It’s also worth inspecting the hydraulic pipes for any scuffs or cuts. Check around the wheel motors too – any hint of oil means a bearing seal has been broken. Replace it immediately or the bill for a new motor could climb to £1,500. Reconditioned ones are closer to £800, so it might be cheaper to replace it than to strip and reassemble. Sands doesn’t recommend fixing it yourself, but if you do then remember to keep things squeaky clean – any contamination can wreak hydrostatic havoc.
7. The 208hp Deutz engine needs taking care of just like any other. Keep an eye on the radiators because heat is the killer of any hydrostatic set-up. Also make sure that the antifreeze-to-water ratio is 50:50 – any more antifreeze in the mix and it can start to corrode the aluminium manifold. Engine oil and and four hydrostatic filters are standard replacement jobs. A set of the latter will cost £130.
8. The tank sight gauge may well need recalibrating. The dry sight uses a stainless steel wire to pull the plunger and usually starts to stretch after a couple of years. Beg, borrow or steal a flow meter to check how much water is going into the tank. The wire can be adjusted accordingly – just get a 13mm spanner on the locking bolt. If you run out of adjustment on the wire then a replacement will cost £8.20. A new sight tube is another £23.
9. Sprayer pumps are prone to occasional leaks as valves and diaphragms tire. Look out for milky oil or fluctuations in the pressure as the pump starts spitting and sucking in air. If there’s a problem then it’s worth replacing all of the diaphragms, valves and O-rings. Four plate bolts hold the pump to the frame – get these undone then whip off the platic-capped pipes and liners. It should be a two-hour job to pull it apart and replace the set of six diaphragms, 12 valves and 12 O-rings, which will cost you £540.
10. Pins and bushes wear with time and are likely to want replacing around the 5,000-hour mark. Sands uses brass bushes to hold boom sections together – a more bulky but reliable alternative to plastic ones. Just knock out the pin and get a pal to hold the boom – a set of four bronze bushes and pins costs £106.