Steering, Suspension, Braking, And Control Systems Flashcards
A dry park test is typically used to diagnose which of the following components?
“A. Upper strut mount
B. Strut bearing
C. Inner tie rod
D. Power steering pump”
“Answer C
A dry park test is designed to test steering linkages by putting road forces on the steering linkages. Steering linkage play is visible and able to be felt when the steering wheel is turned back and forth with the wheels on the ground with vehicle weight on them. “
When performing steering column service work on a vehicle equipped with an air bag, which of the following should be done first?
“A. Pull the SRS fuse and continue working
B. Disconnect both battery cables and wait 20 minutes
C. Disconnect the harness to the air bag controller
D. Connect yourself to ground with a static strap”
"Answer B When working on an air bag system, you need to be aware that the diagnostic module contains capacitors to allow for air bag deployment with the battery disconnected. This means that before performing any work you should disconnect the battery and wait a few minutes for the capacitors to discharge. "
Using a spring scale to measure steering wheel turning effort is necessary while performing which of the following?
“A. Toe adjustment
B. Tie rod replacement
C. Worm bearing preload adjustment
D. Intermediate steering shaft replacement”
“Answer C
While performing a worm-bearing preload adjustment, a spring scale is necessary to make sure that the steering effort is not too great or too little at the wheel. If the effort is too great, the worm-bearing preload must be lessened, and if the effort is too little, the preload must be increased. This will prolong steering box life and allow for comfortable driver steering effort. “
A vehicle with air ride suspension sits too low to the ground but the compressor does work. Which of the following is a likely cause?
“A. Inoperative relay
B. High resistance in the height sensor wiring
C. Blown fuse
D. Inoperative air-exhaust solenoid”
"Answer B If the height sensor wiring has resistance, the control module for the air ride suspension will not signal an air increase to the rear air springs. The height sensor sends feedback to the module on the rear ride height. If the signal is incorrect, the module will not trigger the compressor to increase ride height. "
A vehicle has a groan through the entire rotation of the steering wheel. Which of the following could be the cause?
“A. Dry strut bearing
B. Loose power steering belt
C. Low tire pressure
D. Steering shaft universal joint”
“Answer A
Strut bearings are in place so that the spring will rotate with the strut and not try to coil up as the wheel turns. The bearing is load-bearing, and if it becomes dry or worn, it will tend to make noise as it rotates through normal steering. If it becomes significantly worse, it will tend to seize and snap through steering. “
Which of the following could cause a clunk on heavy acceleration or heavy deceleration?
“A. Strut bearings
B. Outer tie rod end
C. Subframe mounts
D. Engine mounts”
“Answer C
The subframe connects the engine and drivetrain to the body on most unibody-designed vehicles. For vibration reasons, the subframe is attached using long bolts and rubber mounts. As the mounts wear, the torque from the drivetrain can cause the subframe to shift and clunk. Heavy deceleration can also cause the subframe to shift. “
A customer complains of a low brake pedal. Which of the following is correct?
“A. Air in the system
B. Incorrect bleeding procedure used
C. Excessive rotor runout
D. Seized star wheel”
“Answer C
Any time space has to be taken up on a hydraulic system, pedal movement will increase. Although a seized star wheel will not allow rear brake shoes to self-adjust, the amount of clearance between drum and shoe is not known. Excessive rotor runout will knock the piston in the caliper back further than it should. The further the piston is back in the bore, the more fluid needs to be displaced to push the piston out until clamping force can occur. “
A hard brake pedal is noticed. Which of the following is a likely cause?
“A. Defective master cylinder
B. Parking brake stuck partially on
C. Open vacuum check valve
D. Leaking poppet assembly”
“Answer D
In a vacuum booster, the poppet valve controls the atmospheric and vacuum ports. If the valve is leaking from the vacuum portion, atmospheric pressure will be allowed to flow into both halves of the booster. With equal pressures on both halves of the diaphragm, no power assist will be present, resulting in a hard pedal. “
What could cause brake fluid to be found on the carpet in a vehicle?
“A. Leaking booster diaphragm
B. Broken brake line
C. Defective secondary seal on the primary piston
D. Reservoir cap missing”
“Answer C
Brake fluid found on the floor in the vehicle is caused by a leaking master cylinder. The secondary seal on the primary piston in the master allows fluid to leak into the vacuum booster. If enough fluid accumulates in the booster, some can leak out the atmospheric port and onto the carpet. “
During which of the following conditions will a worn left front-sealed bearing generally make noise?
“A. Left turn while accelerating
B. Left turn while decelerating
C. Right turn while accelerating
D. Right turn while decelerating”
“Answer D
Sealed wheel bearings generally make noise when the bearing is loaded. A left front-wheel bearing is loaded the most when turning right and decelerating because of body roll and pitch. “
Which of the following will cause a scalloping wear pattern on a tire?
“A. Weak shock absorbers
B. Incorrect caster angle
C. Incorrect toe angle
D. Shifted belt in tire”
“Answer A
Scalloping of the tire occurs when the tire bounces on the road. The purpose of the shock absorbers is to dampen spring oscillations and keep the tires on the ground. “
Which of the following is a necessary precaution when replacing a pitman arm?
“A. Do not use an air-powered pickle fork
B. Never pry againt the vehicle frame
C. Never heat the pitman arm
D. Never use a screw-type puller”
“Answer C
Replacing a pitman arm can sometimes be a difficult task because the steering gear shaft is tapered. This creates a wedge fit, and after a number of years can be difficult to dislodge with pullers and pickle forks. Many technicians use heat on a pitman arm but find that after the pitman arm is replaced, a power steering leak occurs. This is due to the heat melting the output shaft seal. “
When performing a power steering hydraulic pressure test, the test valve should be closed to test which of the following components?
“A. Pump
B. Control valve
C. Power piston
D. Hoses”
“Answer A
The shut-off valve needs to be closed to check the power steering pump output. When the valve is closed, compare the reading with the manufacturer’s specifications. Note that the valve should not be closed for more than 5 seconds as damage will occur to the power steering pump from overheated fluid. “
Which of the following is the correct way to increase caster on a Macpherson strut suspension system equipped with a strut bar?
“A. Rotate the eccentric on the lost strut mount
B. Rotate the tie rod counter clockwise
C. Adjust the strut bar
D. Add shims to the top of the strut”
“Answer C
Most systems that have a strut bar use the strut bar to adjust caster. Adjusting the strut bar will change the position of the lower control arm and ball joint. “
Which of the following adjustments should be performed first during a 4-wheel alignment?
“A. Front caster
B. Front camber
C. Rear caster
D. Rear camber”
“Answer D
On a 4-wheel alignment, the first adjustment to be made is the rear camber. After rear camber, rear toe should be adjusted and then adjust the front angles. “
What alignment angles will determine subframe misalignment?
“A. SAI and camber
B. SAI and caster
C. Included angle and toe
D. Thrust angle and camber”
“Answer A
If the vehicle and frame centrelines do not match up from the subframe misalignment, SAI and camber angles will not be equal from side to side. The included angle is the addition of SAI and camber. If the included angles are equal but the readings are out of specification, check the alignment of the subframe. “
A single clunk noise heard at every brake application may be caused by which of the following?
“A. Dry caliper sliders
B. Incorrect clearance between caliper and knuckle
C. Weak pad retainer springs
D. A rotor with hot spots”
“Answer B
If there is a large clearance between the caliper and the knuckle where the caliper mounts, with brake application the caliper will grab the rotor, and due to the large clearance, pull it around and peen the knuckle. Clearance on some brake systems can be taken up with shims or increased by filing. “
After replacing a leaking wheel cylinder assembly and bleeding the system, the red brake warning lamp remains illuminated. Which of the following is a likely cause?
“A. Low brake fluid
B. Stuck proportioning valve
C. Defective metering valve
D. Stuck pressure differential valve”
“Answer D
The pressure differential valve compares the brake pressures between each circuit. If there is a failure in the hydraulic system (the leaking wheel cylinder) the pressures will be unequal and cause the switch to close and illuminate the red brake-warning lamp. Some pressure differential valves require resetting after they have been tripped. This would require the removal of the switch, re-centre the valve and re-install the switch. “
On a metering valve-equipped vehicle, no fluid is present on the front wheels during pressure bleeding. What is the most likely cause?
“A. Collapsed front brake hoses
B. Pressure bleeder setting too high
C. Pressure bleeder setting too low
D. Plugged master cylinder compensating port”
“Answer B
Metering valves are designed to delay the application of the front brakes until the rear brakes have started to generate some braking force. This is to provide better brake balance. The metering valve is open until 5-30 psi (34.5-206.8 kPa) and then closes until around 100 psi (689.5 kPa). A pressure bleeder forces fluid through the system. If the setting on the pressure bleeder is too high, it will close the metering valve, stopping the flow of fluid to the front brakes.
high pressure bleeder setting > high pressure > metering valve closed > no fluid to front brakes
low pressure bleeder setting > low pressure > metering valve open > fluid to front break “
A vehicle has an illuminated ABS lamp with a code for Left Front Wheel Erratic (C0227). Which of the following is a likely cause?
“A. Left front wheel speed connector pin tension
B. Open wire in left front harness
C. Shorted connection in left front harness
D. Incorrect sensor gap “
“Answer A
The erratic wheel speed code is usually generated because of intermittent connection. Likely causes are connector pin tension as well as loose connections in the coil of the wheel speed sensor. If an erratic code is generated, focue on the connections at the affected wheel. “
Where is the most accurate spot to take wheel runout measurements?
“A. On the outside of the rim lip
B. Centre of tire tread
C. Inside of wheel rim
D. Wheel flange”
“Answer C
The most accurate place to take wheel runout measurements is on the inside of the rim with the tire removed. Curb damage and dirt can affect measurements taken on the outside of the rim. “
What can cause a serviceable tapered wheel bearing to have scoring only at one end of the roller?
“A. Lack of lubrication
B. Metal fatigue
C. High mileage
D. Excessive preload”
“Answer D
When only one end of the roller has scoring, it is usually caused by excessive preload. This is because the excessive pressure loads on the large end of the tapered roller element. The bearing is too tight and is heating up rapidly while working.”
Which of the following could illuminate the red brake-warning lamp?
“A. Power assist malfunction
B. Maladjusted rear drum brakes
C. Worn brake shoes
D. Broken parking brake pedal return spring”
“Answer D
The brake warning lamp is most likely illuminated by a broken parking brake pedal return spring that does not allow the signal swtich to open.
When the main brake warning light is triggered by a fault in the system, it will be illuminated in red.
If your brake fluid level is too low, typically you will see a similar warning light, only it will be yellow or amber instead of red.”
No fluid is seen squirting from the primary compensating port in the master cylinder reservoir or brake application. Which of the following would be the most likely cause?
“A. Brake pedal pushrod adjustment
B. Defective secondary cup seal
C. Air in the hydraulic circuit
D. Defective master cylinder cap seal”
“Answer A
With no fluid spurting out from the compensation port, the piston is returning insufficiently in the master cylinder bore to uncover the compensating port. The brake pedal pushrod adjustment should be looked at first.”
A rear-wheel-drive sport utility vehicle has a rear brake lock-up condition when the vehicle is lightly loaded. Which of the following would be the most likely cause of this problem?
“A. Defective pressure differential switch
B. Defective metering valve
C. Seized proportioning valve
D. Air in the hydraulic circuit”
“Answer C
Many rear-wheel-drive sport utility vehicles and trucks use a load-sensing proportioning valve to modulate brake pressures in proportion to load. If the valve seizes in the loaded position and the load is removed, excess brake pressure will be applied to the rear brakes and cause lock-up. “
The right front wheel on a diagonally split brake system is excessively hot after a short drive. Which of the following would be the most likely cause?
“A. Warped rotor
B. Collapsed flex line
C. Defective proportioning valve
D. Seized left rear-wheel circuit”
“Answer B
A collapsed flex line can allow fluid flow to the caliper but not away from it. In this event, the right front-wheel brake will stay engaged until the fluid bleeds back through the collapsed line at a slow rate. Excess heat will be formed because the brakes will stay applied after the driver’s foot has been removed from the pedal. “
