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ASE A5 practice questions

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Question 1Hydraulic System Diagnosis and Repair

Which brake fluid is silicone based and should not be mixed with DOT 3 or DOT 4 fluid?

  1. DOT 5 Correct answer.
  2. DOT 5.1
  3. DOT 4
  4. DOT 3

Explanation

DOT 5 is a silicone-based fluid, while DOT 3, DOT 4, and DOT 5.1 are glycol based. Mixing silicone and glycol fluids can cause seal swelling and poor brake performance.

Question 2Hydraulic System Diagnosis and Repair

What is the purpose of bench bleeding a new master cylinder before installation?

  1. To remove air from the master cylinder bore Correct answer.
  2. To set the brake pedal free play
  3. To measure the master cylinder bore diameter
  4. To test the residual pressure valve

Explanation

Bench bleeding expels air trapped in the master cylinder bore and ports before the unit is installed. If that air is not removed, it is pushed into the brake lines and makes pedal bleeding more difficult.

Question 3Hydraulic System Diagnosis and Repair

During gravity bleeding of a brake system, which condition must be maintained?

  1. The reservoir must not run dry Correct answer.
  2. The brake pedal must be held to the floor
  3. The engine must be running at fast idle
  4. The ABS pump motor must be energized

Explanation

Gravity bleeding relies on fluid draining from the reservoir through the lines and out the bleeder. The reservoir level must be watched and kept above the ports so air is not drawn into the system.

Question 4Hydraulic System Diagnosis and Repair

A brake hose bulges visibly when an assistant holds firm pressure on the brake pedal. What is the correct repair?

  1. Flush the brake fluid and retest
  2. Adjust the brake pedal free play
  3. Clean the hose and return it to service
  4. Replace the brake hose Correct answer.

Explanation

A bulge means the hose reinforcement has failed and the hose is expanding under pressure. The hose must be replaced because cleaning or flushing cannot restore its strength.

Question 5Hydraulic System Diagnosis and Repair

A brake pedal slowly sinks toward the floor while steady pressure is held with the engine running. Which condition is the most likely cause?

  1. Glazed brake pads
  2. An internal leak in the master cylinder Correct answer.
  3. Front rotors with excessive lateral runout
  4. Air trapped in the rear brake lines

Explanation

A pedal that sinks steadily under held pressure with no external leak indicates fluid is bypassing the master cylinder cups internally. Air usually causes a spongy pedal, while rotor runout causes pulsation.

Question 6Hydraulic System Diagnosis and Repair

A technician finds the brake fluid in the reservoir is dark and contains gummy sediment. What is the appropriate first action?

  1. Flush the system with specified fluid and inspect it Correct answer.
  2. Top off the reservoir with DOT 5 fluid
  3. Replace only the master cylinder reservoir cap and gasket
  4. Increase brake pedal free play

Explanation

Contaminated fluid should be flushed with the specified fluid, and the system should be inspected for the cause, such as moisture or degraded seals. Adding silicone fluid or replacing only the cap will not correct contaminated fluid.

Question 7Hydraulic System Diagnosis and Repair

A residual pressure check valve is normally used in which type of brake system?

  1. A hydraulic clutch release system
  2. A four-wheel disc system with low-drag calipers
  3. An ABS system to hold pressure during a stop
  4. A drum brake system to hold slight residual pressure Correct answer.

Explanation

A residual check valve holds a small pressure, commonly about 10 psi, in a drum brake system to keep the wheel cylinder cup seals expanded. Disc systems generally use no residual valve or a much lower-pressure valve.

Question 8Hydraulic System Diagnosis and Repair

Which flare type is commonly required for steel brake lines on late-model vehicles?

  1. A single-lap flare with a copper gasket
  2. A push-to-connect fitting
  3. A compression fitting
  4. An ISO or inverted double flare Correct answer.

Explanation

ISO/DIN and inverted double flares are typical for automotive steel brake lines because they seal reliably at high pressure. Single flares and compression fittings are not acceptable for brake hydraulic systems.

Question 9Hydraulic System Diagnosis and Repair

A vehicle has a low brake pedal that rises after several quick pumps but fades again. There are no external leaks. What is the most likely cause?

  1. Air in the hydraulic system Correct answer.
  2. A failed brake booster check valve
  3. Worn front brake pads
  4. A seized caliper slide pin

Explanation

Pumping the pedal temporarily compresses air in the system, which raises the pedal until the air redistributes. Worn pads can lower the pedal but do not cause it to pump up.

Question 10Hydraulic System Diagnosis and Repair

The red BRAKE warning lamp stays illuminated after the parking brake is released and the fluid level is correct. Which component can turn on this lamp?

  1. The pad wear sensor
  2. The pressure differential switch Correct answer.
  3. The brake light switch
  4. The ABS wheel speed sensor at the front hub

Explanation

The pressure differential switch closes when front and rear hydraulic pressures are unequal, such as with a leak in one circuit, and it can illuminate the red warning lamp. Pad wear and wheel speed sensors control different warnings.

Question 11Hydraulic System Diagnosis and Repair

What is the purpose of a metering valve in a disc/drum brake system?

  1. To delay front disc apply until rear drums apply Correct answer.
  2. To maintain residual pressure in the rear circuit
  3. To bleed air from the ABS modulator
  4. To limit rear brake pressure during very hard stops

Explanation

The metering valve holds off front disc brake application briefly so the rear drum brakes can overcome return spring force and begin to apply. This helps balance braking during light to moderate stops.

Question 12Hydraulic System Diagnosis and Repair

A proportioning valve is installed in the rear hydraulic circuit. What does it do during a hard stop?

  1. It holds front brake pressure constant
  2. It routes fluid to the ABS pump during cycling
  3. It limits rear pressure to reduce rear wheel lockup risk Correct answer.
  4. It increases rear hydraulic pressure to improve stopping distance

Explanation

The proportioning valve reduces the rate of rear hydraulic pressure rise after a certain point to help prevent rear wheel lockup. It does not increase rear pressure or control front brake pressure.

Question 13Hydraulic System Diagnosis and Repair

Why is a quick take-up master cylinder used with some low-drag disc brake systems?

  1. To increase fluid boiling point
  2. To move caliper pistons out quickly at low pressure Correct answer.
  3. To provide vacuum assist during engine stall
  4. To keep the rear drum brakes adjusted and reduce pedal travel

Explanation

Low-drag calipers retract their pistons farther, so a quick take-up bore supplies extra fluid volume at low pressure to close the gap quickly. Normal pressure then builds for braking.

Question 14Hydraulic System Diagnosis and Repair

Why should brake fluid be flushed at the manufacturer's recommended interval?

  1. Brake fluid loses its lubricity and wears the master cylinder bore
  2. The dye in brake fluid breaks down and damages seals
  3. Glycol brake fluid absorbs moisture, which lowers its boiling point Correct answer.
  4. Brake fluid thickens and clogs the proportioning valve

Explanation

Glycol-based brake fluid is hygroscopic, so it absorbs moisture from the air over time. Moisture lowers the boiling point and promotes corrosion inside the hydraulic system.

Question 15Hydraulic System Diagnosis and Repair

Which precaution applies when pressure bleeding a brake system?

  1. Pump the brake pedal rapidly while pressure is applied
  2. Leave the master cylinder cap loose to vent air
  3. Disconnect the ABS module before bleeding
  4. Do not exceed the bleeder manufacturer's pressure Correct answer.

Explanation

Pressure bleeding uses a pressurized adapter on the reservoir, and excessive pressure can damage the reservoir or lines. The pressure should be kept at the bleeder manufacturer's recommendation.

Question 16Hydraulic System Diagnosis and Repair

After an ABS hydraulic modulator is replaced, why is a scan-tool-actuated bleed often required?

  1. Air may remain trapped in the modulator circuits Correct answer.
  2. The modulator contains no bleed screws
  3. The scan tool resets the brake pedal position sensor
  4. The scan tool adjusts the proportioning valve spring

Explanation

The scan tool cycles the ABS pump and valves to purge air from internal cavities that manual bleeding may not reach. This is why the service procedure often requires an automated bleed after modulator replacement.

Question 17Hydraulic System Diagnosis and Repair

Brake fluid is found inside the rubber boot of a rear wheel cylinder. What does this indicate?

  1. The residual valve is stuck open
  2. The wheel cylinder cup seals are leaking Correct answer.
  3. Normal assembly lubricant
  4. The brake shoes are contaminated with gear oil

Explanation

Fluid inside the wheel cylinder boot indicates the cup seals are leaking past the piston. The wheel cylinder should be replaced or overhauled, and the brake shoes should be inspected for contamination.

Question 18Hydraulic System Diagnosis and Repair

What can result from insufficient brake pedal free play?

  1. The ABS warning lamp will flash
  2. The rear brakes will apply later than the front
  3. The master cylinder piston may not fully return Correct answer.
  4. The brake pedal will feel spongy and pump up when applied

Explanation

Free play allows the master cylinder piston to return far enough to uncover the compensation port. Without it, fluid cannot vent and the brakes may drag as pressure builds.

Question 19Hydraulic System Diagnosis and Repair

A steel brake line is wet with fluid at the fitting, but the pedal is firm. What is the best first step?

  1. Replace the master cylinder and bench bleed it
  2. Tighten the fitting to specification and recheck for leaks Correct answer.
  3. Add stop-leak additive to the reservoir
  4. Replace all four flexible brake hoses and flush the system

Explanation

A wet fitting should first be cleaned so the leak can be located, then tightened to the specified torque and rechecked. Replacing major components before confirming the source is unnecessary.

Question 20Hydraulic System Diagnosis and Repair

What can happen if a flexible brake hose is twisted during installation?

  1. The hose may restrict flow or fail early Correct answer.
  2. The brake pedal free play will increase
  3. The ABS wheel speed sensor air gap will change
  4. The brake fluid boiling point will decrease

Explanation

Twisting stresses the hose reinforcement and can create an internal restriction or lead to premature failure. Brake hoses should be installed with their orientation marks aligned and without twist.

Question 21Hydraulic System Diagnosis and Repair

A front caliper drags and the wheel is hard to turn. Opening the caliper bleeder screw releases the drag. Which cause is most likely?

  1. A caliper piston seal that is worn and leaking fluid
  2. Air trapped in the caliper hydraulic circuit
  3. A brake rotor with excessive lateral runout
  4. A collapsed brake hose Correct answer.

Explanation

If opening the bleeder releases the drag, pressure was being held upstream of the caliper. A collapsed hose can act like a one-way check valve and trap pressure, and a stuck residual valve can do the same.

Question 22Hydraulic System Diagnosis and Repair

Both front and rear brake pressures are below specification when the pedal is applied, yet the pedal is firm and no fluid is lost. Which condition is most likely?

  1. Air trapped in the hydraulic system after a poor bleed
  2. A leaking wheel cylinder
  3. A worn or undersized master cylinder bore Correct answer.
  4. A metering valve that is sticking partially closed

Explanation

Low pressure at all wheels with a firm pedal and no fluid loss points to the master cylinder not displacing enough volume or building normal pressure. A worn or incorrect bore size can cause this condition.

Question 23Hydraulic System Diagnosis and Repair

During a hard stop, the front wheels lock early while the rear brakes contribute very little. Which valve is most likely misadjusted or stuck?

  1. The pressure differential switch
  2. The metering valve
  3. The residual pressure valve
  4. The proportioning valve Correct answer.

Explanation

The proportioning valve limits rear hydraulic pressure; if it is stuck or incorrectly calibrated, it can over-limit the rear brakes and cause early front lockup. The metering valve controls front apply timing, not rear pressure limiting.

Question 24Hydraulic System Diagnosis and Repair

A master cylinder is being tested with plugs installed in both outlet ports. The pedal is firm at first but slowly falls. What does this indicate?

  1. The outlet plugs are leaking
  2. Fluid is bypassing the primary cup internally Correct answer.
  3. The residual valves are operating as designed
  4. The pushrod is too short

Explanation

With the outlets blocked, a pedal that slowly falls shows fluid is escaping past the primary cup inside the master cylinder. External leakage would be visible at the plugs.

Question 25Hydraulic System Diagnosis and Repair

A vehicle's brake pedal fades during repeated hard stops, but returns after cooling. Which hydraulic condition best explains this?

  1. A leaking caliper piston seal
  2. Fluid boiling in the calipers from absorbed moisture Correct answer.
  3. Air in the system from a loose bleeder screw at one wheel
  4. A clogged master cylinder compensation port

Explanation

Moisture-contaminated brake fluid boils at a lower temperature, creating compressible vapor in the calipers and causing fade that improves as the system cools. A loose bleeder would cause a consistent spongy pedal, not fade that recovers with cooling.

Question 26Hydraulic System Diagnosis and Repair

What is the purpose of the flexible diaphragm inside a brake master cylinder reservoir cap?

  1. It filters debris and metal particles out of the brake fluid as it circulates through the reservoir.
  2. It maintains a fixed pressure inside the reservoir at all times.
  3. It lets the fluid level rise and fall while keeping air and moisture out. Correct answer.
  4. It separates the front and rear hydraulic circuits inside a dual reservoir.

Explanation

The diaphragm seals the reservoir from the atmosphere while flexing to follow fluid level changes as pads wear or fluid expands, which limits moisture absorption. Without it, outside air carrying water vapor would sit directly on the fluid.

Question 27Hydraulic System Diagnosis and Repair

Which statement about DOT 5 silicone brake fluid is accurate?

  1. It has a lower dry boiling point than DOT 3 fluid.
  2. It is the preferred fluid for vehicles equipped with ABS.
  3. It is fully compatible with DOT 3 and DOT 4 fluids and may be mixed with them in any proportion.
  4. It does not absorb moisture and must never be mixed with glycol-based fluid. Correct answer.

Explanation

DOT 5 is silicone based, so it is non-hygroscopic and chemically incompatible with glycol fluids; mixing the two can cause aeration, poor pedal feel, and seal damage. Vehicles specifying DOT 3 or DOT 4, including most ABS-equipped cars, must use the specified glycol fluid.

Question 28Hydraulic System Diagnosis and Repair

Why is a new master cylinder bench bled before it is installed?

  1. To confirm that the pressure differential switch is centered and functioning.
  2. To check the operation of the residual pressure check valve.
  3. To seat the piston cups against the cylinder bore.
  4. To purge air from the bore before it is installed on the vehicle. Correct answer.

Explanation

Bench bleeding pushes air out of the bore and outlet ports before the unit is mounted. Air left inside the master cylinder is very difficult to remove with ordinary wheel-cylinder bleeding once the system is assembled.

Question 29Hydraulic System Diagnosis and Repair

A front caliper was replaced. The pedal now feels spongy and can be pumped up, the reservoir level is correct, and no leaks are visible. What is the most likely cause?

  1. The master cylinder primary cup is bypassing internally.
  2. A flexible brake hose has collapsed internally.
  3. The rear brake shoes are out of adjustment.
  4. Air was trapped in the system during the repair. Correct answer.

Explanation

A pedal that feels spongy and rises with pumping after a hydraulic part is replaced points to trapped air, since brake fluid itself is not compressible but air is. Bleeding the affected circuit, plus an ABS bleed if the modulator was involved, removes it.

Question 30Hydraulic System Diagnosis and Repair

A vehicle pulls to the left only when the brakes are applied. Which condition is the most likely cause?

  1. Air trapped in the left rear hydraulic circuit.
  2. A restricted left front hose or a sticking left front caliper piston.
  3. A restricted right front hose or a sticking right caliper piston. Correct answer.
  4. A leaking seal in the left front caliper piston.

Explanation

The vehicle pulls toward the side producing more braking force, so a right side that is restricted or seized makes the left side dominant. Diagnosing which wheel is doing less work is the key step before replacing parts.

Question 31Hydraulic System Diagnosis and Repair

A caliper is removed to replace a front brake hose. Which practice is correct while the caliper is off?

  1. Support the caliper with wire so the hose is not stretched. Correct answer.
  2. Clamp the hose shut with locking pliers to stop fluid loss.
  3. Loosen the hose bracket on the strut to gain extra length.
  4. Hang the caliper from the flexible hose so it stays clear of the work area.

Explanation

The inner liner and reinforcement of a brake hose can be damaged by tension, sharp bends, or clamping. Supporting the caliper prevents that damage, which could otherwise create an internal restriction and a dragging brake.

Question 32Hydraulic System Diagnosis and Repair

The brake fluid level drops slowly over several weeks, no external leak can be found, and the brakes otherwise work normally. Where is the fluid most likely going?

  1. Past the caliper piston seals and onto the brake pads.
  2. Through the ABS hydraulic modulator and into the accumulator.
  3. Out of the master cylinder reservoir cap vent.
  4. Past the master cylinder rear seal into the booster. Correct answer.

Explanation

A failed rear seal on the master cylinder lets fluid pass into the booster, where it is often drawn into the engine and burned, leaving no puddle. A caliper or wheel cylinder leak, by contrast, leaves visible fluid at the wheel.

Question 33Hydraulic System Diagnosis and Repair

A technician finds cloudy brake fluid, a swollen reservoir cap diaphragm, and several wheel cylinder cups that are soft and enlarged. What do these findings indicate?

  1. The fluid is contaminated with mineral oil or petroleum product. Correct answer.
  2. The fluid has absorbed water and simply needs a routine flush.
  3. The system has been overheated and the fluid has boiled, leaving varnish.
  4. The brake lines contain air left over from a recent repair.

Explanation

Petroleum-based products attack the rubber seals in a brake hydraulic system, causing them to swell and soften, and they do not mix with glycol fluid. Correct repair requires flushing the entire system and replacing all rubber components.

Question 34Hydraulic System Diagnosis and Repair

A light truck was fitted with a rear lowering kit. Since then, the rear wheels lock before the front wheels during hard stops, and the height-sensing proportioning valve linkage is still connected to the rear axle. What is the most likely cause?

  1. The valve linkage is misadjusted, allowing too much rear pressure. Correct answer.
  2. Air is trapped in the rear hydraulic circuit and is cushioning the apply.
  3. The rear brake shoes are glazed and have reduced friction, so the fronts do more work.
  4. The rear wheel cylinders are leaking fluid onto the shoes and linings.

Explanation

Lowering the rear moves the frame closer to the axle, so a height-sensing valve interprets the vehicle as heavily loaded and sends more pressure to the rear brakes. The linkage must be reset to the specified ride height whenever suspension height changes.

Question 35Hydraulic System Diagnosis and Repair

In a drum brake assembly, the brake drum serves as which of these?

  1. A fluid reservoir for the wheel cylinder
  2. A hydraulic pressure multiplier for the wheel cylinder
  3. A friction surface for the shoes Correct answer.
  4. An automatic clearance adjuster for the shoes

Explanation

The drum rotates with the wheel, and its inner machined surface is what the brake shoes press against to create friction and slow the vehicle. It does not multiply hydraulic pressure, adjust clearance, or store fluid.

Question 36Hydraulic System Diagnosis and Repair

Technician A says brake shoes contaminated with brake fluid should be replaced. Technician B says contaminated shoes can be cleaned with solvent and reused. Who is correct?

  1. Both technicians
  2. Technician B only
  3. Neither technician
  4. Technician A only Correct answer.

Explanation

Brake fluid and oil soak into the lining and cannot be removed reliably with solvent; contaminated linings can grab, fade, or pull. The correct repair is to replace the shoes and fix the source of the leak.

Question 37Hydraulic System Diagnosis and Repair

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

  1. A timing light
  2. A drum micrometer Correct answer.
  3. A torque wrench
  4. A feeler gauge

Explanation

A drum micrometer or inside micrometer measures the drum's internal diameter so it can be compared with the maximum diameter cast into the drum. A feeler gauge measures gaps such as shoe-to-drum clearance, not diameter.

Question 38Hydraulic System Diagnosis and Repair

What is the purpose of the star wheel in a drum brake assembly?

  1. It holds the brake shoe against the backing plate
  2. It adjusts shoe clearance as the linings wear Correct answer.
  3. It locks the wheel cylinder piston in its bore
  4. It centers the brake drum on the axle flange

Explanation

The star wheel is the threaded adjuster that changes the rest position of the shoes, compensating for lining wear so pedal travel stays consistent. It does not lock the piston or retain the shoe.

Question 39Hydraulic System Diagnosis and Repair

A brake drum is marked with a maximum inside diameter of 11.060 inches. It measures 11.065 inches. What should the technician do?

  1. Install thicker brake shoes
  2. Install it as is
  3. Replace the drum Correct answer.
  4. Machine it to 11.070 inches

Explanation

A drum that is already beyond its maximum diameter has no safe material left for resurfacing and may overheat or crack. It must be replaced, not machined or used with thicker shoes.

Question 40Hydraulic System Diagnosis and Repair

Which of these is a sign of a leaking wheel cylinder?

  1. Blue discoloration on the outside of the drum
  2. A high, hard brake pedal
  3. A clicking noise from the star wheel
  4. Fluid on the backing plate below the cylinder Correct answer.

Explanation

Brake fluid escaping past the wheel cylinder cups runs down the backing plate and often contaminates the shoes. A high pedal and clicking adjuster are not leak indicators.

Question 41Hydraulic System Diagnosis and Repair

Riveted brake shoe lining should be replaced when which condition is found?

  1. Rivets are within 1/32 inch of the surface Correct answer.
  2. The lining shows a light, even glaze
  3. The lining is dry and covered with light dust
  4. The lining still measures about 1/4 inch thick

Explanation

Lining must be thick enough to hold the rivets away from the drum; when rivets are within about 1/32 inch of the surface, the drum can be scored. Glaze or dust alone does not condemn a shoe.

Question 42Hydraulic System Diagnosis and Repair

When installing new brake shoes, what should be done with the springs and hold-down hardware?

  1. Reuse all springs if they look clean
  2. Reuse hold-down springs but replace return springs
  3. Paint the old springs to prevent corrosion
  4. Replace them with new hardware from the shoe kit Correct answer.

Explanation

Springs weaken and lose tension with heat and age, and old hold-down parts can fail. Brake shoe kits normally include new springs and retainers, and they should be installed.

Question 43Hydraulic System Diagnosis and Repair

A self-adjuster that fails to operate will most likely cause which condition?

  1. Pedal travel grows as linings wear Correct answer.
  2. The wheel cylinder bore becomes oversized
  3. The parking brake cable becomes longer
  4. The brake pedal becomes hard and high

Explanation

Without self-adjustment, the shoes stay retracted as lining wears, so the wheel cylinder must extend farther and pedal travel increases. It does not create a high pedal or change hydraulic bore size.

Question 44Hydraulic System Diagnosis and Repair

Which drum brake design uses the rotation of the drum to force the primary shoe into the secondary shoe?

  1. Duo-servo Correct answer.
  2. Dual-circuit diagonal
  3. Disc with a single piston
  4. Leading-trailing

Explanation

In a duo-servo brake, the primary shoe transfers force through the adjuster strut to the secondary shoe, and both shoes self-energize in forward rotation. A leading-trailing design has one leading and one trailing shoe without that transfer.

Question 45Hydraulic System Diagnosis and Repair

A vehicle pulls to the left only when the brakes are applied. Which test best helps confirm a dragging left rear brake?

  1. Check the brake pedal free play and travel
  2. Compare wheel temperatures after several stops Correct answer.
  3. Measure the inside diameter of both brake drums
  4. Perform an engine intake vacuum test

Explanation

A dragging or sticking brake generates extra heat on that wheel. Comparing temperatures after a series of stops helps identify which side is staying applied.

Question 46Hydraulic System Diagnosis and Repair

Which of these can cause a rear drum brake to drag after the brakes are released?

  1. A glazed brake lining
  2. Worn brake shoe lining
  3. Air trapped in the hydraulic system
  4. An internally failed brake hose Correct answer.

Explanation

A collapsed inner liner in a brake hose can act as a one-way check valve, holding pressure at the wheel after the pedal is released. Air, glaze, and lining wear affect performance but do not trap pressure.

Question 47Hydraulic System Diagnosis and Repair

Why should new brake shoes be arced to match the drum radius?

  1. To increase the effective wheel cylinder bore size
  2. To make the brake shoe return springs softer
  3. To raise the parking brake lever mechanical ratio
  4. To provide full lining contact and reduce fade Correct answer.

Explanation

Arcing grinds the lining to the drum's radius so the whole lining contacts the drum at once. That improves initial braking and reduces hot spots and fade.

Question 48Hydraulic System Diagnosis and Repair

A rear wheel makes a scraping noise that changes with wheel speed. A broken hold-down spring is found inside the drum. What is the most likely result?

  1. The wheel cylinder will begin to leak fluid
  2. The shoe can shift against the drum Correct answer.
  3. The brake hose will collapse internally
  4. The star wheel will overadjust the shoes

Explanation

Hold-down springs keep the shoes against the backing plate; if one breaks, the shoe can move outward and scrape the drum. The other failures listed are unrelated to hold-down hardware.

Question 49Hydraulic System Diagnosis and Repair

Gear oil is found on the brake shoes of a rear drum brake. What is the correct repair?

  1. Clean the shoes with brake cleaner
  2. Replace the axle seal and the shoes Correct answer.
  3. Machine the brake drum only
  4. Adjust the star wheel tighter

Explanation

Gear oil contaminates the lining and cannot be cleaned out safely, so the shoes must be replaced. The leaking axle seal must also be replaced to prevent repeat contamination.

Question 50Hydraulic System Diagnosis and Repair

A brake drum with excessive out-of-round will most likely cause which symptom?

  1. A parking brake that releases slowly
  2. Pulsation or surging during braking Correct answer.
  3. A hard and high brake pedal feel
  4. A constant squeal at all vehicle speeds

Explanation

An out-of-round drum changes shoe-to-drum clearance as it rotates, producing a pulsation felt through the pedal or vehicle. It does not cause a hard pedal or constant squeal.