The most hazardous element used in the composition of brake lining as far as the mechanic is concerned is:
One of the most important reasons air brakes have been chosen over hydraulic brakes in heavy duty vehicles, is that air brake systems are more tolerant to system leaks.
The device used for adjusting the brakes on an S-cam, drum type air brake system is the :
The "S" cam of a foundation brake assembly functions as a:
The air compressor for air brake system is usually pressure lubricated by:
Spring brakes commonly operate the ________________ to keep the vehicle from moving when parked.
At what pressure is the safety valve on the air system set?
Why should air tanks not be field welded?
What is the imperial measurement used to identify the torque capacity of a slack adjuster?
Where might you find desiccant in an air brake system?
The device that controls the air compressor cut-in and cut-out pressure is known as?
A factor that affects stopping distances would be:
An ideal air braking system can be defined as:
What is the angle at the slack adjuster to push-rod when brakes are applied and properly adjusted?
Reservoirs or air tanks must be drained regularly because:
When draining accumulated moisture from the air tanks or reservoirs you should:
The correct method to adjust cam brakes is to rotate the slack adjuster screw:
Technician A says that if the locking collar is defective on a manual slack adjuster the slack adjuster should be replaced. Technician B says that an automatic slack adjuster needs no lubrication due to permanent lubrication. Who is right?
You are servicing a piggyback spring brake assembly. Technician A says no attempt should be made to repair or replace any part of the spring brake portion, but that it should be completely replaced as a unit. Technician B says that the spring chamber should be disarmed (manually released) and safely disabled before discarding. Who is right?
Technician A says that air brakes may be wedge-actuated. Technician B says that air brakes may be cam-actuated. Who is right?
Technician A says that cam-actuated brake systems are still the most common brake system on heavy duty trucks today. Technician B says that air operated disc brakes are becoming more common all the time. Who is right?
In the S-cam foundation brake, the final link between the air system and the foundation brake is:
Technician A says that one of the factors affecting air timing is the size of the lines. Technician B says that if an incorrect air line (i.e., too small) were installed, then the air brake timing/balance will be affected. Who is right?
Technician A says that a slack adjuster must be adjusted so the angle between it and the chamber pushrod is 90 degrees when the brakes are fully applied. Technician B says that the chamber pushrod should be adjusted with the shortest, possible stroke, without dragging the brakes. Who is right?
What is a rule that applies equally to almost all air brake systems?
Why should a slack adjuster need adjusting?
What is one of the most important aspects of air compressor preventative maintenance?
An airbrake system is being inspected. Technician A says that the cylinder pushrod spring, in combination with the brake shoe return spring, releases the brakes. Technician B says that normally, the clevis threads onto the slack adjuster arm. Who is right?
Technician A says that heat cracking of brake drums will cause rapid lining wear. Technician B says that brake drums (over 14 inches in diameter) may be machined 0.125" over normal new diameter safely. Who is right?
Technician A says it''s okay to machine drums, as long as the drum''s manufacturer''s recommendation for machining dimensions are followed. Technician B says that turning a drum oversize will sacrifice its strength. Who is right?
When installing the clevis between the pushrod and slack adjuster, Technician A says that the clevis should be correctly positioned on the pushrod in order to facilitate proper brake adjustment. Technician B says that the clevis on a brake chamber pushrod is keyed into location. Who is right?
Technician A says that it is friction built up in or on the drum/rotor that actually stops a vehicle''s motion. Technician B says it is the shoes/pads being applied against the drums/rotors that actually causes the friction that stops a vehicle''s motion. Who is right?
A wig -wag (low air warning device) should operate:
The range between air compressor cut-in pressure and cut-out pressure is approximately _____________ P.S.I.
The pushrod stroke is being measured. Technician A says that the applied stroke uses an 80-psi brake application. Technician B says the brakes are adjusted (if needed) to achieve the proper free stroke. Who is right?
You are performing an air timing balance test on a combination vehicle. Technician A uses an accurate watch as part of the required equipment. Technician B says that balanced air timing means each axle receives air at the same time and at the same pressure level as needed by the driver. Who is right?
Technician A says when wedge brakes are not properly adjusted, it reduces brake advantage and contributes to poor brake performance. Technician B says that a properly adjusted brake is one where the angle between the slack adjuster and the chamber pushrod is 90 degrees when the brakes are applied. Who is right?
What is brake compounding?
When you are adjusting the tension of the compressor drive belt, you notice contact at the bottom of the pulley with the belt, you should:
Technician A says that a warning light and buzzer that do not function below 60 psi is caused by a defective bulb. Technician B says that an inaccurate pressure sender can be the cause of a warning light and buzzer that stays on above 60-psi supply pressure. Who is right?
New brake linings are being installed on a truck. Technician A says you use the correct procedure to properly re-rivet new linings on. Technician B always greases the platforms on the backing plate before installing new shoes/linings. Who is right?
If the compressor pumps and delivers air well but cuts out at too low a pressure, the ________________should be adjusted.
The moisture that accumulates in the air tanks or reservoirs is a result of:
If compressor build up time is very slow it can be caused by:
A method used to determined whether or not a check valve found between supply and service tanks is functioning properly is to alternately drain the tanks starting with the supply tank.
Poor brake adjustment on cam type air brakes is one of the largest single causes of brake related truck accidents.
One -way check valves prevent air flow from the supply tank to the service tank.
Spring brakes are:
The purpose for having more than one reservoir is:
An air brake chamber identified as type 25 has a
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