1993 GMC Suburban Owner's Manual - Page 359

23. EXHAUST P I ;SURE REGULATOR VALVE INSPECTION* -Check that thevalveworksproperly.Correctanybinding.Inspecthosesforcracks, chafingordecay.Replacepartsasneeded. 24. TIRE AND WHEEL ROTATION AND INSPECTION -Forproperwear (10 000 andmaximumtirelife,rotatetiresatthefirst6,000miles kilometers)forSchedule I (t) or 7,500 miles (12 500 kilometers)for Schedule II (8) andthenevery 15,000 miles (25 000 kilometers) thereafter.Followtheinstructionsandpatternsshown in Section 6. Checktiresforunevenwearordamage. If irregular orprematurewearis apparent,checkwheelalignment. Also, checkfordamagedwheels.See "Tires" in theIndexformoreinformation. Fordualwheels,wheneverthevehicle,wheels,orfastenersarenew, havethewheelfastenertorquesetatthefirst100,1,000and miles(1 60, 1600 and 10 000 km). 6,000 For 3500 H.D. Models,blockthetiresoppositethosebeingremovedto keepthevehiclefromrolling. 25. DRIVE AXLE SERVICE -Checkreadfrontaxlefluidlevelandaddas seals forleaking. needed.Checkconstantvelocityjointsandaxle e Locking differential-Drain fluidatfirstoilchangeandrefill.Check fluidlevelandaddasneeded atsubsequentoilchanges.Industy areas, or trailertowingapplicationsdrainfluidatevery 15,000 miles (24 135kilometers)andrefil1.t Standard differential -Check fluidlevelandaddasneededat every oil change. In dustyareas,ortrailertowingapplications,drain (24 135kilometers)andrefi1l.t fluidevery15,000miles 8 Morefrequentlubricationmay be requiredonheavy-dutyor off-road use. 26, BRAKE SYSTEM INSPECTION W h e n theengineoil is changed, inspectthelinesandhosesforproperhookup,binding,leaks,cracks, chafing,etc.Checktheparkingbrakeadjustment,andthefluidlevel in themastercylinder. A low fluidlevelcanindicateworndiscbrakepads whichmayneed to be serviced.t *AnEmissionControlService t fluid loss in thesesystemsmayindicate A inspectedandrepairedatonce. a problem.Havethem 7-21