Pinpoint Test H: Front Suspension Noise
- H1 ROAD TEST THE VEHICLE
- Test drive the vehicle.
- During the road test, drive the vehicle over a rough road. Using ChassisEARs, determine from which area/component the noise is originating.
- Is there a squeak, creak or rattle noise?
NOTE: An assistant will be needed for this road test.Yes : GO to H2.
No : The suspension system is OK. CONDUCT a diagnosis on other suspect systems.
- H2 INSPECT THE STEERING SYSTEM
- With the vehicle in NEUTRAL, position it on a hoist. Refer to JACKING & LIFTING .
- Check the steering system for wear or damage. Carry out a steering linkage test. Refer STEERING LINKAGE .
- Inspect the tire wear pattern. Refer to TIRE WEAR PATTERNS CHART .
- Are the steering components worn or damaged?
WARNING: The electrical power to the air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle. This can be accomplished by turning off the air suspension switch. Failure to do so can result in unexpected inflation or deflation of the air springs, which can result in shifting of the vehicle during these operations.WARNING: If equipped with fire suppression system, depower the system. For important safety warnings and procedures, refer to FIRE SUPPRESSION SYSTEM .Yes : REPAIR the steering system. INSTALL new components as necessary. TEST the system for normal operation. If equipped with fire suppression system, GO to H7.
No : GO to H3.
- H3 FRONT SHOCK ABSORBER/STRUT CHECK
- Check the front shock absorbers/strut mounts for loose bolts or nuts.
- Check the front shock absorbers/struts for wear or damage. Carry out a "bounce test".
- Are the front shock absorbers/struts loose or damaged?
Yes : TIGHTEN to specifications if loose. INSTALL new front shock absorbers/struts if damaged. TEST the system for normal operation. If equipped with fire suppression system, GO to H7.
No : GO to H4.
- H4 CHECK THE FRONT SPRINGS
- Check the front spring and front spring mounts/brackets for wear or damage.
- Are the front springs or spring mounts/brackets worn or damaged?
Yes : REPAIR or INSTALL new components as necessary. TEST the system for normal operation. If equipped with fire suppression system, GO to H7.
No : GO to H5.
- H5 CHECK THE CONTROL ARMS/RADIUS ARMS
- Inspect the control arm bushings for wear or damage.
- Inspect for twisted or bent control/radius arm.
- Are the control/radius arms damaged or worn?
Yes : REPAIR or INSTALL new components as necessary. TEST the system for normal operation. If equipped with fire suppression system, GO to H7.
No : GO to H6.
- H6 CHECK THE STABILIZER BAR/TRACK BAR
- Check the stabilizer bar/track bar bushings and links for damage or wear.
- Check the stabilizer bar/track bar for damage.
- Check for loose or damaged stabilizer bar isolators or brackets.
- Are the stabilizer bar/track bar components loose, worn or damaged?
Yes : REPAIR or INSTALL new components as necessary. TEST the system for normal operation. If equipped with fire suppression system, GO to H7.
No : Suspension system OK. CONDUCT diagnosis on other suspect systems. If equipped with fire suppression system, GO to H7.
- H7 REPOWER THE FIRE SUPPRESSION SYSTEM WARNING: If equipped with fire suppression system, repower the system. For important safety warnings and procedures, refer to FIRE SUPPRESSION SYSTEM .
- Verify that the fire suppression system is repowered. For additional information, refer to FIRE SUPPRESSION SYSTEM .
- If the fire suppression system repowered?
Yes : Fire suppression system repowering is complete.
No : REFER to FIRE SUPPRESSION SYSTEM for fire suppression system depowering and repowering procedure.