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Massey Ferguson 235 Orchard, MF 245 - Hydrostatic steering system

MF 230, 235, 240, 245, 250 Tractors Repair Operations

Hydrostatic steering

Hydrostatic steering system used on MF 235 Orchard models and all MF 245 models except Vineyard.

Lubrication and bleeding - The hydrostatic steering hand pump and steering cylinder assembly are lubricated by the operating fluid. Permatran Oil is recommended. The system is self bleeding, but steering should be cycled and reservoir refilled as often as necessary until level stops dropping.

Steering cylinder

Overhaul - Two types of steering cylinders have been used. If two steering cylinders are used on Massey Ferguson 235, 245 tractor (Orchard models), both cylinders should be alike. To disassemble the cylinder, remove oil from cylinder by working piston back and forth. Remove rod end and star washer, then unscrew cap. Renew all seals when assembling. Heat Teflon rings in warm oil to soften before installing. Install piston in inner tube from end opposite hole. Do not push piston and seal ring past the hole. Lip of scraper should be out. Lubricate all parts before assembling. Tighten cap to approximately 400 Nm (300 ft-lbs.) torque.

Hydrostatic hand pump

Remove and reinstall - Remove the hydrostatic hand pump, first remove the battery and the steering wheel. Disconnect the oil pressure line at gage and tachometer cable at both ends, then remove the tachometer cable and cable housing. Mark all wires to facilitate reassembly, then disconnect all wires from instrument panel gages. Remove lights from panel gages and disconnect fuel shut-off from injection pump (Massey Ferguson 235, 245 diesel models). Remove the complete instrument panel with gages. Disconnect wires from starter switch and light switch, then unbolt and remove the rear hood assembly wilh starter and light switches installed. Disconnect linkage from both ends of the throttle cross shaft, then slide shaft from left side of tractor. Remove the complete air cleaner assembly and the battery platform. Clean the area thoroughly before disconnecting any power steenng lines. Disconnect the four hydraulic lines and plug all openings to prevent entrance of dirt, then unbolt and remove the hydrostatic hand pump. Reinstall, reverse the removal procedure. Be careful to connect wires to instruments conectly. Bleed the hydraulic system aner all lines are connected. Be sure that system is not allowed to operate without fluid in reservoir.

MF 235, 245 Orchard overhaul

Massey Ferguson 235, 245 Orchard tractors are equipped with a Char-Lynn open center type hydrostatic hand pump. The rotary valve sleeve spool and housing are available as a matched set only. To disassemble the removed unit, first remove cap screws and withdraw end plate, gear set, spacer and drive link as a urut. Unbolt and remove upper housing and input shaft as a unit. Withdraw the control spool and sleeve as a unit from bottom end of housing. Remove Teflon discs, then push pin and centering springs out of sleeve. Carefully slide spool (splined end first) from sleeve. Insert a bent wire through port in valve body and push plug from body, then remove check valve seat using an Allen wrench. Remove check ball and spring. Inspect centering springs for cracks or distortion and renew if necessary. Inspect spacer plates and gear set for wear or scoring. Parts should be renewed if measurable wear exists. Inspect control spool and sleeve and housing bore for nicks, scoring or wear. If any part is damaged, renew steering pump assembly. Renew all O-rings and seals. When assembling the unit, tighten check valve seat to a torque of 17 Nm (150 ft-lbs.).

Assemble spool in sleeve making sure spool rotates smoothly in sleeve. Align spring slots in spool and sleeve, then insert centering springs (two sets of three each) so arched center sections are together. Insert pin into spool and sleeve assembly and install a Teflon disc at each end of pin. Install assembled control spool unit from bottom of valve body using a twisting motion. Do not allow sleeve to move beyond flush with machined surface of metering end of valve body. Install upper housing with input shaft over splined end of spool and onto valve body. Tighten retaining cap screws evenly to 25 Nm (220 ft-lbs.) torque. Be sure pin slot in drive shaft is aligned with a valley of inner rotor to ensure correct timing of control sleeve. If drive slot is improperly aligned, steering unit will operate in reverse or "kick back" when hydraulic pressure is applied. Assemble drive link, spacer, gear set and spacer onto valve body. Note that spacer should be flush with outer surface of gears if drive link is properly engaged with control spool pin. Install end cover and tighten reta ining cap screws evenly to 17 Nm (150 ft-lbs.) torque.

MF 245 Standard models overhaul

All Massey Ferguson 235, 245 tractors except Orchard are equipped with the hydrostatic hand pump. The valve spool and body are available only as a matched set. To disassemble the removed steering control valve assembly, install a fitting in one of the four ports in valve body, then clamp fitting in a vise so input shaft is pointing downward. Remove cap screws and end cover. Lapped surfaces of end cover, 4 commutator set, manifold, stator-rotor set, spacer and valve body must be protected from scratching, burring or any other damage as sealing of these parts depends on their finish and flatness. Remove seal retainer and seal, then carefully remove washer, commutator set and manifold. Grasp spacer and lift off the spacer, drive link and stator-rotor set as an assembly. Separate spacer and drive link from stator-rotor set. Remove unit from vise, then clamp fitting in vise so input shaft is pointing upward. Place a light mark on flange of upper cover and valve body for aid in reassembly. Unbolt upper cover from valve body, then grasp input shaft and remove input shaft, upper cover and valve spool assembly. Remove and discard seal ring. Slide upper cover assembly from input shaft and remove Teflon spacer. Remove shims from cavity in upper cover or from face of thrust washer and note number of shims for aid in reassembly. Remove snap ring and seal assembly. Remove snap ring, thrust washers and thrust bearing from input shaft. Drive out pin and withdraw torsion bar and spacer.

Place end of valve spool on top of bench and rotate input shaft until drive ring falls free, then rotate input shaft clockwise until actuator ball is disengaged from helical groove in input shaft. Withdraw input shaft and remove actuator ball. Do not remove actuator ball retaining spring unless renewal is required. Remove plug and recirculating ball from valve body. Thoroughly clean all parts in a suitable solvent, visually inspect parts and renew any showing excessive wear scoring or other damage. Using a micrometer, measure thickness of the commutator ring and commutator. If commutator ring is 0.038 mm (0.0015 inch) or more thicker than commutator, renew the matched set. Place the stator-rotor set on the lapped surface of end cover. Make certain that vanes and vane springs are installed correctly in slots of the rotor. Arched back of springs must contact vanes. Center opposite lobe on crown of stator, then using two feeler gages, measure clearance between rotor lobes and stator. If clearance is more than 0.15 mm (0.006 inch), renew stator-rotor assembly. Using a micrometer, measure thickness of stator and rotor. If stator is 0.05 mm (0.002 inch) or more thicker than rotor, renew the assembly. Stator, rotot, vanes and vane springs are available only as an assembly. Before reassembling wash all parts in clean solvent and air dry. All parts, unless otherwise indicated, are installed dry. Install recirculating ball and plug with new O-ring in valve body and tighten plug to a torque of 14,19 Nm. Clamp fitting (installed in Massey Ferguson 235, 245 valve body port) in a vise so top end of valve body is facing upward. Install thrust washer, thrust bearing, second thrust washer and snap ring on input shaft. If actuator ball retaining spring was removed, install new retaining spring. Place actuator ball in its seat inside valve spool. Insert input shaft into valve spool engaging the helix and actuator ball with a counterclockwise motion. Use the midsection of torsion bar as a gage between end of valve spool and thrust washer, then place the assembly in a vertical position with end of input shaft resting on a bench. Insert drive ring into valve spool until drive ring is engaged on input shaft spline.

Remove torsion bar gage. Install spacer on torsion bar and insert the assembly into valve spool. Align cross holes in torsion bar and input shaft and install pin. Pin must be pressed mto shaft until end of pin is about 0.8 mm below flush. Place spacer over spool and install spool assembly into valve body. Position original shims on thrust washer, lubricate new seal ring, place seal ring in upper cover and install upper cover assembly. Align the match marks on cover flange and valve body and install cap screws finger tight. Tighten a worm drive type hose clamp around cover flange and valve body to align the outer diameters, then tighten cap screws to a torque of 24-30 Nm. With drive link installed, place spacer plate on valve body with plain side up. Install stator-rotor set over drive link splines and align cap screw holes. Make certain vanes and vane springs are properly installed. Install manifold with circular slotted side up and align cap screw holes with stator, spacer and valve body. Install commutatot ring with slotted side up, then install commutator over drive link end making certain that link end is engaged in the smallest elongated hole in commutator. Install seal and retainer. Apply a few drops of hydraulic fluid on commutator. Use a small amount of grease to stick washer in position over pin on end cover. Install end cover making sure that pin engages center hole in commutator. Align holes and install cap screws. Alternately and progressively tighten cap screws while rotating input shaft. Final tightening should be 24-30 Nm (08-22 fl-lbs.) torque. Relocate the unit in vise so input shaft is up. Lubricate new seal and carefully work seal over shaft and into bore with lip toward inside. Install snap ring with rounded edge inward. Remove unit from vise and remove fitting from port. Turn unit on its side with hose ports upward. Pour clean hydraulic fluid into inlet port, rotate input shaft until fluid appears at outlet port, then plug all ports until installation.