160054, OPR, HYSTER, Hyster2, SRM

//-->.pos {position:absolute; z-index: 0; left: 0px; top: 0px;}INTRODUCTIONGENERALThis section has the description and repair proceduresfor the steering housing and the steering control unit.Additional information on parts of the steering systemare in the following sections:STEERING AXLEandHYDRAULIC SYSTEM.steering cylinder to the steering control unit and then re-turns to the hydraulic tank.Turning the steering wheel actuates three main parts ofthe steering control unit: (1) The spool for the controlsection, (2) the sleeve for the control section and (3) therotor in the metering section. When the steering wheel isnot moving, the spool and sleeve are held in the neutral(center) position by springs. During this time, oil flowsfreely through the steering control unit. The oil does notflow to the steering cylinder.As the steering wheel is turned, the spool just begins torotate. The springs try to move the sleeve to keep theneutral position between the spool and sleeve. However,the force necessary to turn the rotor is greater than thepressure of the springs. The springs begin to bend, let-ting the spool move a small amount within the sleeve.The spool stops moving when it touches the center pin.In this position, the holes in the sleeve and the spool arealigned. Oil coming into the control unit flows to themetering section.More rotation of the steering wheel causes the spool torotate the pin. This action causes the rotation of thesleeve and the rotor in the metering section. The oil thenflows to one side of the steering cylinder. Hydraulic oilfrom the other side of the steering cylinder returnsthrough the control section of the steering control unit.When the steering wheel stops moving, the metering ac-tion in the metering section also stops. The neutral posi-tion springs return the sleeve to the neutral positionstopping oil flow to or from the cylinder. The pressurestays in the steering cylinder to keep the steer tires in po-sition. Oil from the pump flows through the steeringcontrol unit to the tank or other parts of the system. Toreturn the steer wheels to the straight position, the steer-ing wheel must be rotated in the opposite direction. Thesteering control unit will operate as described, but allparts will rotate in the opposite direction.DESCRIPTION (See FIGURE 1.)This section has a description and the repair proceduresfor more than one brand of steering control unit. Theunits are similar in construction and operation with hoseconnections on the side at a manifold or valve block as-sembly. See FIGURE 2. or FIGURE 4. Some manifoldsalso have a relief valve.The steering control unit is a hydrostatic unit that is con-trolled by the steering wheel. The control unit is in-stalled in a housing or on a bracket at the cowl and is op-erated by the column assembly and steering wheel. Thesteering control unit has a control section and a meteringsection.The steering system is a hydraulic system that does nothave a mechanical connection between the steeringwheel and the steering axle. The control of the steeringis through a hydraulic circuit.If the hydraulic pump for the steering system does notoperate, steering is still possible. A check valve permitsthe steering control unit to control the steering cylinder.The lift truck is difficult to steer when the steering pumpis not operating, but the steering control unit can operatethe steering cylinder and make steering possible.OPERATION (See FIGURE 1.)The steering control unit is a rotary valve operated bythe steering wheel. During the steering operation, thesteering control unit controls the direction of flow andamount of oil that flows to the steering cylinder. Thesteering cylinder in the axle actuates the steering linkageto move the steer tires. Hydraulic oil returns from theREPAIRSSTEERING WHEEL AND COLUMNASSEMBLY(See FIGURE 1. through FIGURE 4.)The upper end of the steering shaft has splines for thesteering wheel. A large nut holds the steering wheel ontothe steering shaft. The horn button is the cover for thecenter of the steering wheel. The lower end of the steer-ing shaft has splines or a tang to engage the steering con-trol unit. Contacts at the horn button (see FIGURE 2.), awire in the column and slip ring contacts in the columnassembly (see FIGURE 1.) allow for horn operation bythe operator.15824STEERING SHAFT ASSEMBLY TYPICALOF INTERNAL COMBUSTION UNITSFIGURE 1. STEERING CONTROL UNIT2There are two types of steering column assemblies dis-cussed here; Type “A” and Type “B”. Type “A” has acolumn housing that is a support for the mount bracketof the steering control unit as shown in FIGURE 3. Type“B” has a mount bracket of the steering control unit thatis the support for the column housing as shown inFIGURE 4.The steering column assembly is adjustable and held inposition by a latch. The assembly position can bechanged as needed for operator comfort. An access cov-er on the steering column gives access to the steeringcontrol unit hose connections.6. Remove the two springs for the latch. Remove the twocapscrews, nuts, washers and spacers at the pivot pointsof the column housing. Remove the mount plate.7. Remove the four capscrews, washers, grommets andspacers that fasten the bracket for the steering controlunit to the column housing. Carefully remove the steer-ing control unit, bracket and column from the columnhousing. If necessary, remove the latch assembly fromthe column housing.8. Remove the four screws that fasten the bracket andsteering column to the steering control unit. Do not losethe spacers or washers. Remove the two screws that fas-ten the manifold or valve block to the port side of thesteering control unit. If necessary, disassemble the steer-ing control unit as shown in FIGURE 5.Assembly And Installation(See FIGURE 2. and FIGURE 3.)1. If necessary, assemble the steering control unit asshown in FIGURE 6. Install the manifold or valve blockon the steering control unit using new O–rings. If re-moved, install the latch assembly in the column hous-ing.2. Install the steering column and bracket on the steeringcontrol unit as removed during disassembly. Install thisassembly in the column housing. Do not damage thehorn wire contact (see FIGURE 1.) or column grommet.Make sure to install the grommets, washers and spacersas a sound isolator for the steering control unit.3. Install the two capscrews, nuts, washers and spacersat the pivot points of the column housing and mountplate. Install the two springs for the latch. Install themount plate and column assembly on the cowl of the lifttruck.TYPE “A” STEERING COLUMNASSEMBLYRemoval And Disassembly(See FIGURE 2. and FIGURE 3.)CAUTIONDisconnect the negative battery cable on internalcombustion trucks. Disconnect the battery connec-tor on electric trucks. Disconnect the battery beforeremoving the covers.1. Attach a tag on the battery connector or negative cablestating “DO NOT CONNECT BATTERY”. Move thesteering column to the most forward position. Removethe access cover from the steering column.2. Put tags for identification on the hydraulic hoses at thesteering control unit so that they can be connected cor-rectly during assembly. Disconnect the hydraulic hosesat the bottom of the manifold or valve block. Installplugs at all hoses and ports to prevent dirt from enteringthe steering hydraulic system.3. Carefully lift the horn switch at the center of the steer-ing wheel and pull the switch wire out of the steeringshaft. See FIGURE 1. Pull the switch assembly out ofthe steering wheel and disconnect it. Remove the nut. Ifpossible to install, use a puller to remove the steeringwheel.4. Put tags for identification on the meters and gaugewires at the steering column housing so that they can beconnected correctly during assembly. Also put a tag onthe horn wire. See FIGURE 1. Disconnect all wires.5. Remove the capscrews that fasten the mount plate tothe cowl and remove the steering column assembly fromthe lift truck.WARNINGThe hydraulic hoses MUST be connected to the cor-rect ports and fittings or the steering system will notoperate as expected. This operation that is not ex-pected can cause damage or personal injury. Makesure the hoses are identified and connected correctly.4. Install all wires and hoses as removed during disas-sembly. Install the steering wheel and nut. Push the hornswitch wire into the steering shaft and install the switchin the steering wheel. Install the access plate, remove thebattery tag and connect the battery connector or cable.31.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.STEERING WHEELHORN BUTTON ASSEMBLYNUTFASTENERPLUGBRACKETSPACERCAPSCREWWASHERLATCH BRACKETGROMMETSPACERSPRINGCOWL8GROMMET9STEERING COLUMN12 101123145671617H20.00–32.00F/FS(H440–700F/FS) SHOWN.OTHERS SIMILAR.18151319211420252126222225232728191717.18.19.20.21.22.23.24.25.26.27.28.24STEERING COLUMN HOUSINGSTEERING CONTROL UNITMANIFOLD BLOCKLATCHCOVERTILT BRACKETHOSE CLAMPSPACERSPRINGPINTYPE “A” STEERING COLUMNCAPSCREWO–RING (2)12398FIGURE 2. STEERING WHEEL AND STEERING COLUMN ASSEMBLY4TYPE “A” STEERING COLUMN11.2.3.4.5.6.STEERING WHEELHORN BUTTON ASSEMBLYSTEERING COLUMN GROMMETSTEERING COLUMN HOUSINGLATCH BRACKETSPRING2H8.00–16.00XL (H165–360XL) SHOWN.OTHERS SIMILAR.34910581166121377.8.9.10.11.12.13.MOUNT PLATELATCHBRACKETCOVERSTEERING COLUMNSTEERING CONTROL UNITMANIFOLD BLOCKFIGURE 3. STEERING WHEEL AND STEERING COLUMN ASSEMBLY5

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