Spo 116

At what speed do you complete a brake pedal test?

0 mph

Based on Pascal's law, if a one-square-inch master cylinder moves two inches, what distance will a two-square-inch master cylinder move?

1 inch

When pressure-bleeding a brake system, the pressure-bleeder tank needs to be at least how full of brake fluid?

1/3

Hydraulic brake boosters are used in which model of U-Haul equipment?

2005-2016 JH

In the event of a vacuum-source interruption, a check valve in the booster reserves enough vacuum for approximately how many power-assisted stops?

3

What tool is used to measure the park-brake pad thickness on a GMC TM U-Haul truck?

3/32" drill bit

How many measuring points on a rotor should be checked to determine if the rotor is within thickness variation tolerance?

4

When performing your monthly service of your AMMCO 4100 Lathe, how much oil is to be replaced in the gear box.

9 oz.

What is recommended by GMC as a quick check gauge to measure scoring depth on rotors?

A dime

A rotor does not have to be machined when there is:

A new replacement rotor installed.

What needs to be completely out of the brake system before disconnecting the bleeding equipment?

Air

After verifying concerns, complete a quick visual inspection. Diagnostics begin with a quick visual inspection. Inspect for:

All of the above

Lateral run-out can be caused by:

All of the above.

Vehicle pulling right or left while braking can be caused by:

All of the above.

Which is a main cause of warped rotors?

All of the above.

Which of the following is a part of Strategy-Based Diagnostics?

All of the above.

Which of the following is a reason the BRAKE warning light would be on?

All of the above.

Which of the following is part of Strategy-Based Diagnostics?

All of the above.

What does ABS stand for?

Anti-lock braking system

Which brake drum component takes the brake force from the brake shoes?

Backing plate

The addition of a brake __________ results in easier braking application.

Booster

What tool is used to measure the inside diameter of the brake drum?

Brake drum micrometer

The master cylinder converts what motion into hydraulic pressure?

Brake foot pedal

Technicians inspecting working on U-Haul trucks and trailers should have a solid working knowledge of which of the following?

Brake systems

After you have verified that the rotor is properly mounted to the brake lathe, in which direction is the cross feed hand-wheel turned for the tool bits to approach the rotor face?

Counterclockwise

Vehicle speed is monitored by what?

Dedicated ECU

When diagnosing a potential vacuum-booster-related problem the following causes could create what condition?

Excessive pedal effort

A faulty check valve will not allow vacuum to bleed out of the booster, causing a hard brake pedal.

False

A single-piston disc brake caliper can apply more force than a dual-piston disc brake caliper.

False

A twin cutter tool is used to recondition one surface at a time for the brake rotor.

False

As disc brake pads wear, the caliper piston moves inward to compensate for pad wear.

False

Engine vacuum is a higher pressure than atmospheric pressure when applied to the front of the booster diaphragm.

False

If you see excessive run-out on the rotor, check the rotor mounting by loosening the arbor nut and turning the rotor 360° by hand on the arbor.

False

It is acceptable to use a clamping tool to restrict brake fluid flow in a rubber brake line.

False

It's OK to allow a brake caliper to hang by its rubber brake hose while servicing the brakes.

False

Liquids are similar to air and gases in that they are all compressible.

False

Mixing different brands of D.O.T.-approved brake fluid will damage their chemical properties when under pressure.

False

Replacement drums should always be refinished prior to installing.

False

Setting the parking brake will adjust the rear brakes on all U-Haul vehicles.

False

The master cylinder has a single bore separated into two separate chambers by the lead and trailing pushrods.

False

The primary braking systems utilized on all U-Haul equipment are the foot-operated main braking system and the hydro-boost assist.

False

When performing a brake service, you should remove the caliper and allow it to hang from a rubber hose until service is completed.

False

A key difference between floating and fixed calipers is?

Fixed calipers move pads on both sides hydraulically.

What are the primary braking systems utilized on U-Haul equipment?

Foot operated main braking system Manual park brake

What will be the result if air is trapped in a brake system?

Increased brake pedal travel.

From the list below, select which type of energy can be converted into heat energy?

Kinetic

What are the two types of brake shoes on a drum brake system?

Leading and trailing

What are the two types of brake shoes on a drum brake system?

Leading and trailing Primary and secondary

Heat causes both __________ fading and ____________ fading.

Mechanical and Lining

There are primarily two types of brake fading caused by heat.

Mechanical fade Lining fade

What two valves control brake pressure distribution?

Metering and proportioning

Hydraulic pressure can be calculated with which of the following formulas?

P=F/A

What is the physical law that governs hydraulic brake systems?

Pascal's law

If a flare nut is over-tightened, the brake line fitting could collapse resulting in:

Pressure change.

The brake proportioning valve is located on what circuit?

Rear brake hydraulic circuit

The pressure proportioning valve reduces what in order to prevent early lockup?

Rear tire braking force

When wrapping the drum silencer band snugly around the drum, be sure it covers what?

Right edge

A brake rotor rotates at what speed?

Same speed as the wheel.

What is the proper method to test parking brake operation?

Set the parking brake, then put the transmission in gear.

TSB stands for:

Technical service bulletin.

After the brakes have been applied and released, the fluid returns from the wheel cylinders to the brake fluid reservoir through _________.

The compensation port.

Which tool is used in U-Haul shops to measure brake shoe lining thickness?

Tire-tread depth gauge

What is the purpose of the slit or groove found the face of some replacement brake pads?

To indicate wear of disc brake pads

What is the purpose of the slit or groove found on the face of some replacement brake pads?

To indicate wear of disc brake pads To allow an exit for brake dust and gasses generated during braking

A floating caliper applies braking pressure against the outboard brake pad.

True

After examining the scratch cuts, if the first and second cuts are opposite one another, remove the drum from the arbor, check the mounting adapters and arbor for nicks, burrs or chips, remount the drum and repeat the scratch-cut process.

True

Air in the brake system and a leak in the brake system are the two primary causes of a spongy brake pedal.

True

Always start the brake fluid vacuuming process at the wheel farthest from the master cylinder.

True

Always use the backing plate to help eliminate drum vibration during turning.

True

An ABS system is capable of modulating the brake pressure at a given wheel up to 15 times per second.

True

If the brake pedal sinks slightly when the engine is started while depressing the pedal, the booster is operating normally.

True

If the scratch cuts are side by side, run-out or wobble is caused by rotor condition.

True

If you have no evidence of any brake fluid leaks, and your brake pedal fades to the floor, the master cylinder has a fault.

True

Spindle-speed adjustment is accomplished by moving the three-position speed adjustment lever up or down to achieve 100, 150 or 200 RPM choices.

True

The ABS ECU judges the slip ratio of each wheel and instructs the actuator to provide the optimum braking pressure to each wheel.

True

The correct method to calculate maximum booster output is: pressure difference x diaphragm + input force.

True

The double chuck will automatically self-center the rotor.

True

The drum brake has been more widely used on U-Haul trailers than any other brake design.

True

When braking occurs, converted heat is absorbed primarily by the brake rotor or drum and dissipated to the surrounding air.

True

When only the ABS light is on, there is no effect on normal braking performance.

True

When the brakes are not applied, the piston cups are positioned between the inlet port and the compensating port in both chambers.

True

A common cause of disc brake squeal is:

Wear indicators touching rotor surface.

What is the leading cause of drum brake failure?

Wheel cylinder leakage

What is created when a brake pad contacts the rotor?

all the above

If you see excessive runout on the rotor, check the rotor mounting by loosening the arbor nut and turning the rotor 360° by hand on the arbor.

false

Mixing different brands of D.O.T.-approved brake fluid will damage the chemical properties under pressure.

false

The best way to request access to the Ford and GM websites is to call the U-Haul Technical Center.

false

Any brake service repair or replacement should always include a final test-drive to verify that all repairs and adjustments have been made.

true