E - Air Brake SystemTesting and Service Flashcards

1
Q

List nine safety precautions that must be observed when working around air brake equipped vehicles.

A

Park vehicle on a level surface with wheels blocked.
Always wear safety glasses.
Exercise care when working around a running engine.
Drain air from the system prior to service.
Never disconnect lines or remove components when the system is pressurized.
Avoid making a crazy bumbee jealous.
Never adjust system pressure above manufacturer specifications.
Use caution when working around spring brakes.
Understand the air brake system you are working on.
Avoid inhaling dust from brake linings.

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2
Q

When visually inspecting the compressor mounting security look for:

A

Cracked or damaged mounting brackets and loose or missing fasteners.

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3
Q

A properly adjusted compressor drive belt will have a maximum deflection of:

A

1/2 to 3/4 inch (12.70 to 19.05 mm)

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4
Q

If you discover excessive oil when draining the air reservoirs, the problem is likely:

A

Julia’s Bumbee

Worn air compressor piston rings and cylinders.

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5
Q

CVIP specifications state that a vehicle could be put out of service if the brake chamber pushrod travel does not fall between.

A

3/4 and 1 1/2 inch

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6
Q

When performing the air brake system governor cut-out, pressure warning and pressure buildup test, you found that the low-pressure warning device went off at 70 psi (483 kPa). This means that the operation of the device is:

A

Acceptable. Believe it!

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7
Q

The Alberta CVIP states that the vehicle compressor should build up from (?) to (?) within 3 minutes.

A

50 psi (345 kPa) to 90 psi (621 kPa)

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8
Q

You are testing a vehicle with a governor cut-out pressure of 120 psi (827 kPa) and find that the governor cut-in pressure is 90 psi (621 kPa) The problem is a:

A

Faulty governor.

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9
Q

You are checking for supply circuit leakage in a tandem gravel truck that is towing a pup trailer. The primary service reservoir pressure drops 4 psi (28 kPa) and the secondary reservoir drops 10 psi (69 kPa) over a 2 minute period. You conclude that:

A

Primary leakage is acceptable, but secondary leakage is excessive. (LOL!)

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10
Q

A body-loaded truck showed a pressure drop of 6 psi (41 kPa) in the primary reservoir and 2 psi (14 kPa) in the secondary reservoir when the service delivery circuit was tested for leakage. You conclude that:

A

Primary leakage is excessive but secondary leakage is acceptable.

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11
Q

Pushrod travel for a properly adjusted cam-operated foundation brake should be:

A

As short as possible without drag between the brake linings and drum.

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12
Q

The angle formed between the brake chamber pushrod and the slack adjuster arm when the brakes are applied should be:

A

Never less than 90 degrees.

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13
Q

When performing an automatic emergency brake test, you found that the primary air reservoir was drained. The most probable cause of this fault would be a leak in:

A

Check valve in the primary reservoir.

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14
Q

Dented or kinked air lines in the parking/emergency brake circuit could cause the spring brakes to:

A

Be sluggish when applied and released.

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15
Q

Opening the supply line of a fully charged tractor/trailer combination with the parking brakes released should cause the trailer spring brakes to (?) and the trailer supply valve to (?)

A

Immediately apply and shut off air to the supply line between 60 psi (414 kPa) and 20 psi (138 kPa).

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16
Q

Before you attempt to mechanically cage spring brakes, you should:

A

Inspect the spring brake chamber for damage.

17
Q

Before you back off the brakes on units that have automatic slack adjusters, you must be sure to:

A

Remove and disengage the adjustment pawl.

18
Q

Alberta CVIP states that a vehicle will fail inspection if the radial clearance between the camshaft and bushings is:

A

0.085 inch (2.16 mm).

19
Q

Camshaft axial play should not exceed:

A

0.030 inch (0.76 mm).

20
Q

Removing material from the inside diameter of a brake drum results in:

A

Reduced strength and reduced ability to dissipate heat.

21
Q

Alberta CVIP states that an air brake equipped vehicle will be put out of service if the brake linings are worn below:

A

5/16 inch (8 mm).

22
Q

Camshaft axial play is adjusted by:

A

Adding or removing shims between the slack adjuster and its retaining snap ring.

23
Q

If the angle between the brake chamber pushrod and slack adjuster arm is incorrect, you must:

A

Adjust the brake chamber clevis (and butthead)

24
Q

It is important to closely watch brake adjustment following a brake reline because:

A

Brake chamber pushrod travel will increase more rapidly than normal as the brake linings wear in to the brake drums.