© 2012 Delmar, Cengage Learning Underhood and Body Inspection (Vehicle on Ground) Chapter 13

© 2012 Delmar, Cengage Learning Objectives Pinpoint safety items in need of attention Perform on-ground brake system checks Perform on-ground steering and suspension checks Perform an exhaust system inspection Be knowledgeable about vehicle body service

© 2012 Delmar, Cengage Learning Objectives (cont'd.) Perform fuel systems checks Perform cooling system checks Perform electrical systems checks Safely and competently perform a complete underhood service

© 2012 Delmar, Cengage Learning Introduction During inspection items needing repair are located and documented –Underhood and body inspections are done while car is on the ground –Senior personnel may work the “lube rack” Better able to spot needed repairs –Lube personnel may earn a commission Responsibilities include inspection, diagnosis, and documenting problems

© 2012 Delmar, Cengage Learning Brake System Inspection Only obvious conditions are inspected –Complete inspection not included in lube service Brake pedal travel and feel –Brake pedal travel should not be too low –Pedal should feel firm when applied –Pump breaks rapidly to check drum brake adjustment Parking break travel and adjustment –Fully applied at one-half full travel of handle –Adjust drum brakes before emergency brake

© 2012 Delmar, Cengage Learning Brake System Inspection (cont’d.) Inspecting brake and clutch fluid –Clean the top of the cover before removing to avoid contamination –When fluid is low a more complete inspection is required Master cylinder is wet Backing plates on drum brakes wet Tires streaked with fluid and dirt Fluid level drops when disc brake pads wear Dirty fluid indicates a need for service

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Brake System Inspection (cont’d.) Disc lining inspection –Each pad should be as thick as its metal back –Systems to warn the driver brake pads are worn: Electronic sensor illuminates a dash light Electronic sensor pulsates the pedal Metal tab on disc brake lining causes noise –Outer edges of disc brake pads Can usually be seen through an opening in the outside of the brake caliper Is usually necessary to remove tire and wheel to perform the inspection

© 2012 Delmar, Cengage Learning On-Ground Steering and Suspension Checks Steering looseness –Steering wheel should have a minimum freeplay Steering fluid level –Checked when hot with engine off Manual steering gears use different fluids Check shock absorbers (vehicle on ground) –Check to see that the vehicle sits level –Push on each bumper to check shock resistance Normal shocks allow spring to rebound only once –Check again while car is in the air

© 2012 Delmar, Cengage Learning

Fuel System Inspection Check for leaks and inspect all fuel hoses –See that they are not cracked, hard, or leaking Air filter –Cleans the air entering the engine –Air must not leak past the filter into the engine Dirt is main cause of engine failure –Check the air filter by shining a light through it See that there are no small holes in the paper Crankcase ventilation system –Positive crankcase ventilation system

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Cooling System Inspection Visual inspection –Radiator cap pressure relief valve, upper sealing gasket, and vacuum valve Coolant inspection –Visually inspect coolant for chemical breakdown –Coolant strength is checked with hydrometer Cooling system leaks: pressure test Inspect cooling system hoses –Should not be swollen or cracked –Oil damages rubber cooling system hoses

© 2012 Delmar, Cengage Learning

Belt Inspection Visually inspect accessory drive belts –Belts should not be cracked or glazed –Belts may be V-belts or V-ribbed belts V-belt accessory drive belt tension test –With engine off, turn a pulley by hand to see if belt slips –If the AC generator belt is too loose, it will not keep the battery charged

© 2012 Delmar, Cengage Learning Electrical System Inspection Look for obvious problems –Bare or burned wires –AC generator and ignition system connections –Loose or corroded connections Battery check –Look for damaged or corroded battery cable clamps Battery electrolyte level –Clean water may be added to replenish electrolyte

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Check Operation of Lights Inspect operation of all lights –Check lenses for cracks –Check instrument panel lights Some lights require a key to test them Excessive voltage can burn out bulbs Shine headlights against a wall to inspect aim –Check low beams and high beams

© 2012 Delmar, Cengage Learning Visibility Checks Check windows for damage, condition of weather stripping rubber, and operation Mirrors should not be cracked or fogged Blower motor of heater and defroster should work Duct hoses should be in good condition Wiper arms should not hit window trim and should contact entire glass surface Washer should work on driver and passenger side, be aimed correctly, with sufficient fluid

© 2012 Delmar, Cengage Learning Visibility Checks (cont'd.) Wiper blades must clean the window and contact evenly across the entire blade –Replace entire arm if blade spring breaks Replace wiper blades once or twice a year –Replacing entire arm may be as economical Removing and replacing wiper arm –Raise it as high as it goes –Release the clip on the slide latch –Pry the arm off using two screwdrivers

© 2012 Delmar, Cengage Learning

Other Safety Checks and Service Additional considerations –Horn –Hood latches –Door striker plate –Door locks –Seat belts General safety check –May please customers and increase loyalty

© 2012 Delmar, Cengage Learning

Other Safety Checks and Service (cont'd.) Automatic transmission fluid check –Precautions Check fluid level when fluid is hot Be sure parking brake is set and vehicle is level –Check fluid condition Burnt smell may indicate transmission damage Milky fluid may be contaminated –Automatic transmission fluid Colored with red dye Composed of mineral oil and additives

© 2012 Delmar, Cengage Learning Other Safety Checks and Service (cont'd.) Tires –Check for wear Check tire pressure –Monthly when tire is cold Typically loses about one or two pounds of air pressure a month Engine and transmission mounts –Two people are needed to check engine mounts Set emergency brake Put the car in gear: observe mount on one side Put car in reverse: observe mount on other side