Underhood and Body Inspection (Vehicle on Ground)

1. Underhood and Body Inspection (Vehicle on Ground) Chapter 13

2. 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

3. Objectives (cont'd.) • Perform fuel systems checks • Perform cooling system checks • Perform electrical systems checks • Safely and competently perform a complete underhood service

4. 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

5. 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

6. 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

8. 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

9. 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

11. 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

13. 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

15. 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

16. 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

18. 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

19. 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

20. 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

22. 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

24. 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

25. 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