Case IH Precision Hoe 800 Air Drill Service Manual (incl. Wiring)

Remove the metering discs and inspect for dust packing, cracked flights, or debris bridging the seed cells. Clean or replace worn discs. Check the air system for blockages at each run tube — any partial restriction causes uneven seed distribution across rows. Verify seeder hopper gaskets are sealing; a compromised gasket bleeds air pressure and disrupts metering. Consult the troubleshooting procedures starting on page 485 for depth and seeding uniformity diagnostics.

Start by sequencing the hydraulic system per : connect to tractor, cycle the circuit to purge air, and verify pressure holds at each stage. Check all fittings — 1/4-inch O-ring boss fittings torque to 20 Nm max and 1/4-inch 37° flared lines to 18 Nm min (page 21). If pressure still bleeds off, pull the valve block and overhaul per , inspecting seals and spool bores for wear or scoring.

Check frame leveling first. Level the booms and toolbar frames per the procedures, adjusting caster height until all openers contact soil uniformly. Inspect depth control bearings for wear — a loose bearing lets the opener pivot arm float under load. Confirm packer wheel bolts are torqued to 149 N·m (page 482) and that no packer tires are flat, which shifts weight distribution and causes uneven opener penetration across the toolbar.

Torque V-bolts on the opener head bracket to exactly 122.0 N·m (90 lb ft) per page 486 — over-torque is the primary shear cause on this machine. Inspect the opener head bracket for hairline cracks before reinstalling. Verify the shank is fully seated in the bracket before tightening; any gap concentrates load at the thread engagement zone. If bolts continue breaking, check the toolbar for twist that puts side-load on the opener assembly.

Check tire pressure on the single caster outer wing tires: inflate to 410 kPa (page 327) and verify wheel bolts are torqued to 170 Nm. Low pressure accelerates soil packing in the tread. Inspect caster alignment on page 336 — a toe-in or toe-out condition drags the tire sidewall through soil instead of rolling cleanly. If mud buildup persists, confirm the tire size matches the specified 11L x 15FI (D) and that no bent axle is forcing the wheel to run at an angle.

Measure valve solenoid coil resistance at the connector pins: a healthy solenoid reads between 4 Ω and 8 Ω (page 176). Outside that range, replace the solenoid before suspecting the Rate ECU. When repairing connector terminals, strip wire to 4 +/- 0.5 mm and crimp per page 419 using the correct DTM or WeatherPack tooling — undersized strip length causes a cold crimp that reads in-spec cold but fails under vibration. Clear the fault code and retest the circuit before returning the drill to field use.