Welger AP 53 service schedule

1. Park on level ground, disengage the PTO, stop the tractor engine, take the key out and apply the brakes. Wait until the flywheel has stopped completely: it keeps turning for a while after the PTO is off.
2. Take off the crank guard.
3. Remove the filler bolt (with breather), the level bolt and the drain bolt, and drain the oil.
4. Clean and refit the drain bolt.
5. Fill with SAE 90 hypoid oil until it reaches the level bolt hole (about 1 L), then refit the level and filler bolts.
6. Refit the crank guard before running the baler.
7. New or rebuilt gearbox: change the oil after the first 10 hours.

Tools: Drain tray, Spanners, Funnel, Gloves

1. Disengage the PTO, stop the tractor engine, take the key out and apply the brakes. Wait until the flywheel has stopped completely.
2. Set the knotter trip safety latch to 'Aus' (off), so the needles can't come up while you work.
3. Wear gloves: the knotter knife and needle tips are sharp.
4. Loosen the lock nut and bolts, take off the leaf spring and remove the knotter unit as the manual shows.
5. Knock out the expanding pins, pull out the twine retainer and knotter bill, put a light coat of lithium grease on the shafts and wipe off the excess.
6. Keep grease off the retainer taper and the twine clamp: grease there lets the twine slip and the knots fail.
7. Refit everything with the pins in the right pinion positions.
8. Check the settings: twine tensioner spring length 26 mm; twine flicker gap 1–2 mm at its forward position; twine guide plate gap 1.5–2.5 mm; twine retainer spring preloaded 5 mm (bolt down to the spring, then 3½ turns).
9. Turn the flywheel by hand only, with the PTO shaft off the tractor.
10. Before the next season, clean the knotter beaks and twine retainers so the twine is held and can't wind round the retainer shaft.

Tools: Spanners, Pin punch, Feeler gauge, Rule, Rags, Gloves

1. Take the PTO shaft off the tractor, stop the engine and take the key out. Wait until the flywheel has stopped completely.
2. AP 42/53: remove the clutch plates (2) of the front overrun clutch and clean any grease off the faces with emery paper. Refit them.
3. Don't remove the plate spring completely. The torque is set at the factory; only reset it if the plates are worn, using the shims behind or in front of the spring.
4. Check the shear bolt behind the flywheel is an M7 × 50 grade 8.8. Never fit a stronger bolt. Carry spares.
5. AP 38/48 have a single slip clutch with a shear bolt instead: check it the same way.
6. Needle shear bolt: if it has broken, take out the expanding pin and pin, free the needle lift rod, remove the broken bolt and fit a new Welger bolt 0901.98.10.00. Tighten it carefully.
7. Pick-up slip clutch: set to 300–450 Nm. Never lock it solid.
8. Refit all guards before the PTO shaft goes back on.

Tools: Spanners, Pin punch, Emery paper, Rags

1. Park on level ground, disengage the PTO, stop the tractor engine, take the key out and apply the brakes. Wait until the flywheel has stopped.
2. Clean the protective grease off the tractor and baler PTO splines.
3. Check the PTO shaft: 330–600 mm between the PTO end and the drawbar hole, and at least 300 mm of tube overlap when driving straight. Shorten the inner and outer tubes by the same amount if needed.
4. Fit the PTO shaft so the slide pins snap in at both ends and fix the guard chain to the drawbar.
5. Clean the knotter beaks and twine retainers.
6. Put 4 twine balls side by side, upright, in the twine box, and thread them as the manual shows.
7. Grease all points with lithium grease until old grease comes out of the bearing sides. Clean each nipple first. Never grease the baler while it is running.
8. Check the lights and indicators work and are clean. Carry two wheel chocks on the baler.
9. Check the PTO speed with a watch from time to time: 540 rpm gives 100 ram strokes a minute.
10. New or repaired baler: tighten all bolts and nuts inside and outside after the first 20 working hours.

Tools: Spanners, Grease gun (lithium grease), Tape measure, Watch

1. Take the PTO shaft off, stop the tractor engine and take the key out. Wait until the flywheel has stopped.
2. Clean the baler thoroughly, including the knotter and chamber.
3. Cover all knotter parts with grease (but not the retainer taper or twine clamp).
4. Tighten all bolts and nuts.
5. Check all moving parts move easily.
6. Replace damaged and missing parts.
7. Touch up the paint where needed.
8. Store the baler in a dry place, with the drawbar jack down.

Tools: Brush and air line, Grease gun, Spanners, Touch-up paint