DIAGNOSIS AND TESTING - LOWER CONTROL ARM
Inspect the lower control arm for signs of damage from contact with the ground or road debris. If the lower control arm shows any sign of damage, look for distortion. Do not attempt to repair or straighten a broken or bent lower control arm. If damaged, the lower control arm is serviced only as a complete component.
Inspect both lower control arm isolator bushings for severe deterioration and replace the lower control arm as required.
DIAGNOSIS AND TESTING - LOWER BALL JOINT
- Raise the vehicle allowing the front suspension to hang.
- Remove the tire and wheel assembly.
- Using Dial Indicator (special tool #C-3339A, Set, Dial Indicator), or equivalent, attach the dial indicator mount to the knuckle and align the dial indicator's plunger with the direction of the stud axis, touching the end of the ball joint stud in the lower control arm.
- Push up on the lower control arm and zero the dial indicator. NOTE: Use care when applying load to the knuckle as to avoid damaging the ball joint seal boot.
- From the front of the vehicle, insert a pry bar between the knuckle and lower control arm, resting it on the lower control arm. Use lever principle to push the knuckle up from the lower control arm. Apply the load until the needle of the dial indicator no longer moves.
- Record the ball joint movement. The end play is acceptable if no more than 1.0 mm (0.039 in.) of end play is achieved back-to-back.
- Perform this procedure on each side of the vehicle as necessary.
DIAGNOSIS AND TESTING - HUB AND BEARING - NOISE
Note. The wheel bearing is designed to last for the life of the vehicle and requires no type of periodic maintenance.
Bearings will produce noise if worn or damaged. The noise will generally change when the bearings are loaded. A road test of the vehicle is normally required to determine if there is a bearing noise, or if it may be some other component, and to assist in finding the location. The following procedure, together with the DIAGNOSTIC CHART , should help determine the proper cause. Note that if a particular vehicle road test maneuver, steering to the right for instance, results in noise only part of the time, it is not likely a faulty bearing. Bearing noises are not typically intermittent.
Note. Damaged bearing seals and the resulting excessive grease loss may also require bearing replacement. Moderate grease seepage from the bearing is considered normal and should not require replacement of the wheel bearing. Wheel bearings are designed to last the life of the vehicle and require no type of periodic maintenance. To diagnose the hub, measure hub runout. Refer to ROTOR, BRAKE, DIAGNOSIS AND TESTING .
DIAGNOSTIC PROCEDURE
- Perform drive evaluation. Find a smooth level road surface void of traffic or obstructions. Turn off any accessories which may cause background noise. Evaluate for noise at 50 km/h (30 mph) and 100 km/h (60 mph) and with vehicle in neutral to eliminate potential drivetrain noises. With vehicle at a constant speed, steer back and forth to left and right (approximately 45 degree steering input each way). This will load and unload the bearings and may change the noise level. When bearing damage is slight, the noise is sometimes noticeable at lower speeds and at other times is more noticeable at higher speeds.
- Drive evaluation results: Noise increase when turning right may indicate a problem with the left bearing. Noise increase when turning left may indicate a problem with the right bearing.
- Put vehicle up on hoist. Grab the tire by pushing in on the top center and pulling out on the bottom center to check for excessive movement in the bearing.
- Check for potential rubbing on rotating components, such as rotor splash shields, heat shields touching propshaft or halfshaft, wheel well liners contacting tire, wheel cover on wheel, etc. Any cyclic noise (once per wheel revolution for example) is not likely a wheel bearing fault.
- Remove the wheel and tire assembly, disc brake caliper and brake rotor. Refer to «ROTOR, BRAKE, DIAGNOSIS AND TESTING»(ref-646213-S39931096352014072800000) .
- Rotate the wheel hub, checking for resistance or roughness.
- Any roughness or resistance to rotation may indicate dirt intrusion or a failed hub bearing. If the bearing exhibits any of these conditions, the hub & bearing will require replacement. Do not attempt to disassemble the bearing for repair.
- Rotate the wheel hub, utilize Chassis Ears (or equivalent) to check for noise.
- If none of the above checks indicate a bearing failure, refer to the DIAGNOSTIC CHART for other possible causes.
DIAGNOSTIC CHART - HUB & BEARING
| CONDITION | POSSIBLE CAUSES | POTENTIAL CORRECTIONS |
|---|---|---|
| FRONT END WHINE ON TURNS | 1. Low Power Steering Fluid Level (if applicable) | 1. Fill power steering fluid reservoir to proper level, check for leaks (make sure all air is bled from system fluid) |
| 2. Worn Tires and/or Incorrect Wheel Alignment | 2. Replace Tires, Check And Reset Wheel Alignment | |
| 3. Defective Wheel Bearing | 3. Replace Wheel Bearing | |
| 4. Wrong Power Steering Fluid (if applicable) | 4. Replace With Correct Power Steering Fluid | |
| FRONT END GROWL OR GRINDING ON TURNS | 1. Loose Wheel Lug Nuts | 1. Verify Wheel Lug Nut Torque |
| 2. Engine Mount Grounding Against Frame Or Body Of Vehicle | 2. Check For Engine Mount Hitting Frame Rail And Reposition Engine As Required | |
| 3. Worn Tires and/or Incorrect Wheel Alignment | 3. Replace Tires, Check and Reset Wheel Alignment | |
| 4. Defective Wheel Bearing | 4. Replace Wheel Bearing | |
| 5. Worn or Broken C/V Joint | 5. Replace C/V Joint | |
| 6. Engine Not Centered, Causing Axle Half Shaft to Bottom Out | 6. Center the Engine | |
| POPPING/CLICKING/SNAPPING DURING ACCELERATION AFTER DRIVE-TO-REVERSE SHIFT, REVERSE-TO-DRIVE SHIFT OR WHILE TURNING | 1. Insufficient Hub Nut Torque | 1. Torque Hub Nut to Spec |
| 2. Insufficient Grease on Mating Surface of Axle Half Shaft Outer C/V Joint to Wheel Hub/Bearing, or Worn/Damaged Gasket | 2. Separate Half Shaft From Hub and Bearing and Wipe Mating Surfaces Clean. Apply Light Coating of Wheel Bearing Grease to C/V Joint Surface and Reassemble, or Replace Gasket. Torque Hub Nut to Spec | |
| WHINE/HUM/ROAR WITH VEHICLE GOING STRAIGHT AT A CONSTANT SPEED | 1. Worn Tires and/or Incorrect Wheel Alignment | 1. Replace Tires and Reset Wheel Alignment |
| 2. Defective Wheel Bearing | 2. Replace Wheel Bearing | |
| GROWL OR GRINDING WITH VEHICLE GOING STRAIGHT AT A CONSTANT SPEED | 1. Engine Mount Grinding Against Frame or Body | 1. Check and Reposition Engine as Required |
| 2. Defective Wheel Bearing | 2. Replace Wheel Bearing | |
| 3. Worn or Broken C/V Joint | 3. Replace C/V Joint |
DIAGNOSIS AND TESTING - KNUCKLE
The front suspension knuckle is not a repairable component of the front suspension. It must be replaced if found to be damaged in any way. If it is determined that the knuckle is bent when servicing the vehicle, no attempt is to be made to straighten the knuckle.
DIAGNOSIS AND TESTING - STRUT ASSEMBLY
Inspect the strut assembly for the following conditions
- Inspect for a damaged or broken coil spring.
- Inspect for a torn or damaged dust shield.
- Lift the dust shield and inspect the strut assembly for evidence of fluid running from the upper end of the strut fluid reservoir. (Actual leakage will be a stream of fluid running down the side and dripping off lower end of unit). A slight amount of seepage between the strut shaft and strut shaft seal is not unusual and does not affect performance of the strut assembly.
- Inspect the jounce bumper for signs of damage or deterioration.
- Inspect the clearance between the shock tower and the coil spring. Make sure no fasteners are protruding through the shock tower possibly contacting the coil spring and strut. Because of the minimum clearance in this area, installation of metal fasteners could damage the coil spring coating and lead to a corrosion failure of the spring.