Part No. 102916 S-100 • S-105 • S-120 • S-125 4 - 45June 2011 Section 4 • Repair ProceduresREV A4-4Extension CylindersThe primary boom extension cylinder is locatedinside the boom assembly and incorporates cablesand pulleys that are responsible for extending thenumber 2 and 3 boom tubes. The secondary boomextension cylinder (S-120 and S-125 models) islocated underneath the number 0 boom tube and isresponsible for extending the number 1 boom tube.The extension cylinders are equipped withcounterbalance valves to prevent movement in theevent of a hydraulic line failure.How to Remove the PrimaryBoom Extension CylinderBodily injury hazard. Thisprocedure requires specific repairskills, lifting equipment and asuitable workshop. Attempting thisprocedure without these skills andtools could result in death orserious injury and significantcomponent damage. Dealerservice is strongly recommended.Note: When removing a hose assembly or fitting,the O-ring on the fitting and/or hose end must bereplaced and then torqued to specification duringinstallation.Refer to Section Two,Hydraulic Hose and FittingTorque Specifications.1 Raise the boom to a horizontal position.2 Remove the retaining fasteners from the boomend cover at the pivot end of the boom.Remove the cover from the machine.BOOM COMPONENTS3 Remove the access cover retaining fastenersfrom both sides of the boom. Remove theaccess covers.4 Secure the number 2 and number 3 boom tubestogether with a strap or chain to prevent themfrom moving.5 Remove the cable clamp from the cable breaklimit switch wiring.a cable break limit switch6 Disconnect the wiring connector from the cablebreak limit switch.7 Tag, disconnect and plug the hydraulic hosesfrom the primary boom extension cylinder. Capthe fittings on the cylinder.Bodily injury hazard. Sprayinghydraulic oil can penetrate andburn skin. Loosen hydraulicconnections very slowly to allowthe oil pressure to dissipategradually. Do not allow oil tosquirt or spray.a
