JLG 26MRT, Service & Maintenance

Page 1: ...ie Australia Telephone 065 811111 Fax 065 810122 EUROPEAN OFFICE JLG INDUSTRIES EUROPE Kilmartin Place Tannochside Park Uddingston Scotland G71 5PH Telephone 01698 811005 Main Fax 01698 811055 Parts Fax 01698 811455 CORPORATE OFFICE JLG INDUSTRIES INC 1 JLG Drive McConnellsburg PA 17233 9533 USA Telephone 717 485 5161 Fax 717 485 6417 ...

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Page 3: ...t should be noted that the machines hydraulic sys tems operate at extremely high potentially danger ous pressures Every effort should be made to relieve any system pressure prior to disconnecting or removing any portion of the system Relieve system pressure by cycling the applicable control several times with the engine stopped and ignition on to direct any line pressure back into the reservoir Pr...

Page 4: ...INTRODUCTION MAINTENANCE SAFETY PRECAUTIONS b JLG Sizzor 3120791 REVISON LOG Original Issue June 1993 Revised May 19 1999 Revised December 6 1999 ...

Page 5: ...Guidelines 2 1 2 3 Lubrication Information 2 2 2 4 Cylinders Theory Of Operation 2 3 2 5 Valves Theory Of Operation 2 3 2 6 Component Functional Description 2 4 2 7 Wear Pads 2 4 2 8 Cylinder Checking Procedures 2 4 2 9 Lift Cylinder Removal and Installation 2 5 2 10 Lift Cylinder Repair 2 5 2 11 Steer Cylinder Repair 2 10 2 12 Tilt Alarm Switch Adjustment If Equipped 2 12 2 13 Limit Switch Adjust...

Page 6: ... Interpretation 2 23 2 20 Brake Assembly 2 25 2 21 ADDCO Adjustments Gasoline Dual Fuel Engine 2 27 2 22 ADDCO Adjustments Diesel Engine 2 28 2 23 Valve Driver Card 2 29 3 1 Electrical Schematic Yanmar Sheet of 1 of 2 3 10 3 2 Electrical Schematic Yanmar Sheet of 2 of 2 3 11 3 3 Electrical Schematic Daihatsu Sheet 1 of 2 3 12 3 4 Electrical Schematic Daihatsu Sheet 2 of 2 3 13 3 5 Hydraulic Schema...

Page 7: ... 5 quarts 2 4 liters Drive Pump Closed loop piston type Output 15 gpm 56 8 lpm 3 000 rpm Displacement 1 16 in 3 rev 19 0 cm3 rev Lift Steer Pump Gear type Output 3 1 gpm 11 7 lpm 3 000 rpm Displacement 0 24 in 3 rev 4 0 cm3 rev Steer Drive System Steer Front Tires Dico Multi Trac C S 26 x 12 00 12 NHS 6 ply inflate to 40 psi 2 8 bar Toe In Adjust to 1 4 inch 6 4 mm overall Drive Rear Tires Dico Tr...

Page 8: ...mobile hydraulic system ser vice JLG Industries recommends Mobilfluid 424 hydraulic oil which has an SAE viscosity of 10W 30 and a viscosity index of 152 When temperatures remain consistently below 20 F 7 C an amount of no 2 diesel fuel not to exceed 20 of system capacity may be added to the hydraulic oil reservoir This diesel fuel will thin the hydraulic oil for easier cold weather operation and ...

Page 9: ... position 1 10 MAJOR COMPONENT WEIGHTS 1 11 CRITICAL STABILITY WEIGHTS DO NOT REPLACE ITEMS CRITICAL TO STABILITY SUCH AS ENGINES AXLES OR TIRES WITH ITEMS OF DIFFERENT WEIGHT OR SPECIFICATION DO NOT MODIFY UNIT IN ANY WAY TO AFFECT STABILITY Table 1 2 Lubrication Specifications KEY SPECIFICATIONS MPG MultipurposeGreasehavingaminimumdripping pointof350degressF Excellentwaterresistance andadhesiveq...

Page 10: ...hange EPGL 150 1200 KEY TO LUBRICANTS EO Engine Oil EPGL Extreme Pressure Gear Lubricant HO Hydraulic Oil Mobilfluid 424 MPG Multi purpose Grease TO AVOID PERSONAL INJURY USE SAFETY PROP FOR ALL MAINTENANCE REQUIREING PLATFORM TO BE ELEVATED NOTE 1 Be sure to lubricate like items on each side 2 Recommended lubricating intervals are based on maching operations under normal conditions For machines u...

Page 11: ...SECTION 1 SPECIFICATIONS 3120791 JLG Sizzor 1 5 Figure 1 2 Serial Number Locations ...

Page 12: ...SECTION 1 SPECIFICATIONS 1 6 JLG Sizzor 3120791 Figure 1 3 Torque Chart ...

Page 13: ...e discon nected clear adjacent areas as well as the openings and fittings themselves As soon as a line or compo nent is disconnected cap or cover all openings to prevent entry of foreign matter 3 Clean and inspect all parts during servicing or main tenance and assure that all passages and openings are unobstructed Cover all parts to keep them clean Be sure all parts are clean before they are insta...

Page 14: ...teries Clean batteries using a non metallic brush and a solution of baking soda and water Rinse with clean water After cleaning thoroughly dry batteries and coat terminals with an anti corrosion compound Lubrication and Servicing Components and assemblies requiring lubrication and servicing are shown in Section 1 2 3 LUBRICATION INFORMATION Hydraulic System 1 The primary enemy of a hydraulic syste...

Page 15: ...r systems incorporate double acting cylinders A double acting cylinder is one that requires oil flow to operate the cylinder rod in both directions Directing oil by actuating the corresponding control valve to the piston side of the cylinder forces the piston to travel toward the rod end of the barrel extending the cylinder rod piston attached to rod When the oil flow is stopped movement of the ro...

Page 16: ...ift Cylinder Counterbalance Manual Descent Valve The lift cylinder counterbalance manual descent valve is located on top of the lift cylinder The counterbalance valve is used to hold the platform in place when raised A cable is connected to the valve which when pulled manu ally opens the lift down port and allows the platform to be lowered in the event hydraulic power is lost 2 7 WEAR PADS Sliding...

Page 17: ...r inner arm assembly Using a suitable brass drift drive out the rod end attach pin from the arm assembly 3 Retract the lift cylinder rod completely 4 Tag and disconnect the hydraulic lines then cap the lift cylinder hydraulic lines and ports 5 Remove the bolt and locknut securing the barrel end attach pin to the lower arm assembly Using a suit able brass drift drive out the barrel end attach pin f...

Page 18: ...ER BARREL SURFACES 8 With the barrel clamped securely apply pressure to the rod pulling device and carefully withdraw the complete rod assembly from the cylinder barrel 9 Using suitable protection clamp the cylinder rod in a vise or similar holding fixture as close to the piston as possible 10 If applicable loosen and remove the nut which attaches the piston to the rod then remove the pis ton from...

Page 19: ...t rod and barrel bearings for signs of correct lubrication and excessive wear If necessary replace bearings as follows a Thoroughly clean steel bushing hole of burrs dirt etc to facilitate bearing installation b Inspect steel bushing for wear or other damage If steel bushing is worn or damaged rod or bar rel as applicable must be replaced c Lubricate inside of steel bushing with WD 40 prior to bea...

Page 20: ...ng and back up rings in the inner piston diameter groove 7 Using suitable protection clamp the cylinder rod in a vise or similar holding fixture as close to the piston as possible 8 Carefully thread the piston on the cylinder rod hand tight ensuring that the o ring and back up rings are not damaged or dislodged 9 Thread the piston onto the rod until it abuts the spacer end and install the tapered ...

Page 21: ...ntinue pushing the rod into the barrel until the cyl inder head gland can be inserted into the cylinder barrel 16 Secure the cylinder head gland using the washer ring and socket head bolts 17 After the cylinder has been reassembled the rod should be pushed all the way in fully retracted prior to the reinstallation of any holding valve or valves 18 If applicable install the cartridge type holding v...

Page 22: ...ch wheel by hand to give clearance to remove the steer cylinder from the front axle 4 Carefully lift the steer cylinder until the cylinder mounting block clears the mounting slot in the bot tom of the axle then slowly remove the cylinder from the axle and place it in a suitable work area Disassembly DISASSEMBLY OF THE CYLINDER SHOULD BE PERFORMED ON A CLEAN WORK SURFACE IN A DIRT FREE WORK AREA 1 ...

Page 23: ...rrs and sharp edges Dress applicable surfaces as necessary 7 Inspect the inside diameter of the spacers and heads for scoring or other damage and for ovality and tapering Replace as necessary 8 Inspect the seal and o ring grooves in the heads for burrs and sharp edges Dress applicable surfaces as necessary 9 Inspect the outside diameter of the spacers and heads for scoring or other damage and oval...

Page 24: ...essary is leveling the switch on the spring loaded studs There are two methods of adjustment a manual adjust ment and an adjustment using a voltmeter PERFORM TILT ALARM SWITCH LEVELING PROCEDURE A MINI MUM OF EVERY SIX MONTHS TO ENSURE PROPER OPERATION AND ADJUSTMENT OF SWITCH Manual Adjustment 1 Park the machine on a flat level surface and ensure the machine is level NOTE Ensure switch mounting b...

Page 25: ...all functions must be operated from the platform control station in order to achieve full pump speed It may be necessary to use an assistant to adjust the pressure settings while oper ating the functions from the platform control station Lift Relief Adjustments 1 Install a pressure gauge at gauge port MP located on the lower right side of the valve body The port is identified by a stamping on the ...

Page 26: ...ssure gauge from gauge port MP 2 15 DRIVE AXLE REPAIR Axle Removal 1 Chock the front wheels of the machine securely 2 Using a suitable jack or other lifting equipment raise the rear end of the machine Support the machine on suitable jack stands or other appropriate support ing equipment 3 Carefully remove the five wheel nuts securing each wheel and tire assembly to the drive axle and remove the re...

Page 27: ...ning operation 8 If the wheel bearings are to be re used proceed to Cleaning and Inspection If the wheel bearings are to be replaced proceed to step 6 9 Place the axle shaft in a vise Drill a 1 4 inch 6 4 mm hole in the outside of the bearing retaining ring to a depth approximately three quarters of the thick ness of the ring Do not drill all the way through the ring the drill could damage the axl...

Page 28: ...SECTION 2 PROCEDURES 2 16 JLG Sizzor 3120791 Figure 2 16 Drive Axle Assembly ...

Page 29: ...hers Dana part nos SP 5026 and SP3020 through the holes in the adapter and into the flange plate 4 Tighten the bolts alternately and evenly making sure that the bearing is not cocked on the axle shaft Continue until the wheel bearing is seated To make sure the bearing is seated use a 0 0015 inch 0 0381 mm feeler gauge between the bearing seat and the bearing If the gauge enters force the bear ing ...

Page 30: ...ring the dial indicator spread the housing slightly to facilitate removal of the differential case DO NOT SPREAD THE HOUSING MORE THAN 0 020 INCHES 0 508 MM 5 Pry the differential case from the carrier housing with two pry bars Remove the spreader after the differen tial case has been removed Use caution to avoid damage to the ring and pinion Mark on a tag which side the bearing cups came from 6 R...

Page 31: ...ttach the ring gear to the case using new ring gear screws Tighten the screws alternately and evenly Using a suitable torque wrench Dana part no C 524 A or equivalent torque the screws to 45 60 ft lbs 61 81 Nm 3 Inspect the differential case hubs and remove all nicks burrs dirt etc from hubs to allow master bearings to rotate freely Install new master differen tial bearings Dana part no D 135 or e...

Page 32: ...n a clockwise direction If the indicator starts to travel in a counter clockwise direction this means that the center top of the arbor has been passed Record only the read ing when the indicator is at the highest point This reading indicates the amount of shims necessary to obtain the correct shim pack plus or minus the etching on the bottom end of the pinion If the etching is zero 0 the shim pack...

Page 33: ...ntial bearing using the same tools used in step 4 6 Install a spreader and indicator and carefully spread the carrier housing but DO NOT spread the carrier over 0 015 inches 0 381 mm Remove the indica tor 7 Assemble the differential bearing cups to the differ ential bearing cones Install the differential assembly into the carrier housing 8 Install the differential assembly into the carrier hous in...

Page 34: ... of backlash change obtained will vary depending upon the ratio and gear size High backlash is corrected by moving the ring gear closer to the pinion Low backlash is corrected by moving the ring gear away from the pinion These corrections are made by switching shims from one side of the differential case to the other NOTE When making changes note that two variables are involved Example If you have...

Page 35: ... pattern concave side of gear moves lower and toward the toe Increasing backlash moves the ring gear away from the pinion Drive pattern moves slightly higher and toward the heel Coast pattern moves higher and toward the heel Thicker pinion position shim with the backlash con stant moves the pinion closer to the ring gear Drive pattern moves deeper on the tooth flank contact and slightly toward the...

Page 36: ...tall the retaining ring into the cover 4 If disassembled install the outer spline onto the shaft and secure in place with the retaining ring 5 Press the spline shaft assembly into the bearing until the shaft bottoms on the shaft shoulder The bearing inner race must be supported during this operation 6 Install the retaining ring on the shaft 7 Install the back up rings on the piston toward the spri...

Page 37: ...SECTION 2 PROCEDURES 3120791 JLG Sizzor 2 25 Figure 2 20 Brake Assembly ...

Page 38: ...ed or bled of air See the Yan mar Instruction Manual for the proper procedure 1 Open the engine hood to gain access to the RPM adjustments 2 Disconnect the wire harness from the ADDCO throt tle and install JLG wire harness 4921850 to the ADDCO and the engine harness as shown in Figure 8 24 Start the engine and allow it to come up to operating temperature Adjust the IDLE screw CW higher or CCW lowe...

Page 39: ...SECTION 2 PROCEDURES 3120791 JLG Sizzor 2 27 Figure 2 21 ADDCO Adjustments Gasoline Dual Fuel Engine ...

Page 40: ...SECTION 2 PROCEDURES 2 28 JLG Sizzor 3120791 Figure 2 22 ADDCO Adjustments Diesel Engine ...

Page 41: ...est harness to adjust trimpots P1 through P4 6 Energize drive forward and hold the joystick at FULL ON Make sure the speed switch is set to high speed 7 Turn P4 drive forward low clockwise until the wheels just start to move The ammeter should read about 0 4 Amps or 400 mA This value is approxi mate the reading will be slightly different from one machine to another NOTE Adjusting the low setting a...

Page 42: ...ow long it takes until the meter reads 1 1 A or 1100 mA It should take about 5 seconds Adjust P5 to obtain 5 seconds Horsepower Card Test Before starting this procedure all hydraulic relief pressure settings and engine RPM settings should be set and the engine warmed to operating temperature Refer to Figure 2 23 Valve Driver Card A voltmeter will be required to perform the test 1 Elevate the drive...

Page 43: ...ine Inspection Report form Forms are supplied with each new machine and are also available from JLG Customer Service Form must be completed and returned to JLG Industries JLG INDUSTRIES REQUIRES THAT A COMPLETE ANNUAL INSPECTION BE PERFORMED IN ACCORDANCE WITH THE ANNUAL MACHINE INSPECTION REPORT FORM NOTE This machine requires periodic safety and mainte nance inspections be a JLG Dealer A decal l...

Page 44: ...ump 1 5 7 Valves 1 5 8 HydraulicFilter SeeLubricationChart 5 14 14 9 HydraulicHosesandTubing 1 5 10 HydraulicOilTank 3 5 4 11 HydraulicTankBreather 6 14 12 FuelTank 3 5 4 13 LiftCylinder 1 12 5 6 13 4 14 LimitSwitch 1 7 15 TiltAlarmSwitch 1 7 16 PlacardsandDecals 1 2 17 WheelandTireAssemblies 1 8 9 18 DriveMotors 1 5 6 19 DriveBrakes 1 6 8 20 DriveTorqueHubs 1 3 5 6 21 SteerCylinder 1 5 6 13 4 22 ...

Page 45: ...n every effort has been made to ensure that all likely problems in these areas are given the fullest possible treatment In the remaining machine groups only those problems which are symptomatic of greater problems which have more than one probable cause and remedy are included This means that problems for which the probable cause and remedy may be immediately obvious are not listed in this section...

Page 46: ...ity placard Hydraulic system oil low Replenish oil as necessary Restricted or broken hydraulic line or fit ting Clean repair or replace line or fitting Control valve not functioning properly Repair or replace valve Lift cylinder not functioning properly Repair or replace lift cylinder Enginedoesnotrespondwhenliftcontrol switch is moved to up position Refer to Electrical System Troubleshoot ing No ...

Page 47: ...or replace valve Worn seals in lift cylinder Replace seals Lift cylinder not functioning properly Repair or replace lift cylinder Platform drifts down Manual lowering valve not functioning properly Repair or replace valve Worn seals in lift cylinder Replace seals Holding valve on lift cylinder not function ing properly Repair or replace valve High Drive does not operate below horizontal Damaged wi...

Page 48: ...Microcircuit on controller improperly adjusted Adjust microswitch on controller for proper operation Machine will not travel forward Enable switch not activated Activate enable switch Drive controller not activated within three seconds after enable switch is activated Activateenableswitch thenactivatedrive controller within three seconds Enable circuit not functioning properly Replace enable circu...

Page 49: ...nuity test on wires Repair or replace wires as necessary High speed limit switch not functioning properly Repair or replace limit switch Loose or damaged wiring in valve wiring harness Ensure proper connection of wires at ter minal strip Using suitable test meter per form continuity test on wires Repair or replace wires as necessary SteeringSystem No response to steer control switch on controller ...

Page 50: ...wires Repair or replace wires as neces sary Solenoid valve not functioning properly Repair or replace valve Restricted or broken hydraulic line on valve bank or hydraulic pump Clean repair or replace line Relief valve improperly set ornot function ing properly Reset repair or replace valve as neces sary Steer cylinder not functioning properly Repair or replace cylinder Machine will not steer left ...

Page 51: ...too high Drain system and replace with recom mended oil Refer to Hydraulic Oil Main relief valve set too high Adjust relief valve to proper pressure Hydraulic system oil low Replenish oil as necessary Pump not delivering oil Defective pump Repair or replace pump System pressure too low Main relief valve set too low Reset valve as required Hydraulic pump not functioning properly Repair or replace p...

Page 52: ...oned properly Placeapplicableemergencystop switch toon Power selector switch on ground control box not positioned properly Place power selector switch to platform or ground as required Circuit breaker open Determine and correct cause Reset cir cuit breaker No voltage present at emergency stop switch Check battery cable from battery to emergency stop switch for proper con nection or damage Repair o...

Page 53: ...ine forproperconnectionordamage Repair or replace cable as necessary No voltage present at applicable control valve coil Check applicable wire for proper con nection at terminal strip valve harness plug pin valve harness receptacle pin and valve coil Using suitable test meter perform continuity check on wires Repair or replace harness as necessary NO TERMINAL STRIPS No voltage supplied from termin...

Page 54: ...SECTION 3 TROUBLESHOOTING 3 10 JLG Sizzor 3120791 Figure 3 1 Electrical Schematic Yanmar Sheet of 1 of 2 ...

Page 55: ...SECTION 3 TROUBLESHOOTING 3120791 JLG Sizzor 3 11 Figure 3 2 Electrical Schematic Yanmar Sheet of 2 of 2 1870102 C ...

Page 56: ...SECTION 3 TROUBLESHOOTING 3 12 JLG Sizzor 3120791 Figure 3 3 Electrical Schematic Daihatsu Sheet 1 of 2 ...

Page 57: ...SECTION 3 TROUBLESHOOTING 3120791 JLG Sizzor 3 13 Figure 3 4 Electrical Schematic Daihatsu Sheet 2 of 2 1870103 C ...

Page 58: ...SECTION 3 TROUBLESHOOTING 3 14 JLG Sizzor 3120791 Figure 3 5 Hydraulic Schematic Sheet 1 of 2 ...

Page 59: ...SECTION 3 TROUBLESHOOTING 3120791 JLG Sizzor 3 15 Figure 3 6 Hydraulic Schematic Sheet 2 of 2 1282590 L ...

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