DSL-204 Chap 38 Hydraulic and Air-Over-Hydraulic Fundamentals

Technician A says that a more significant advantage for hydraulic brakes over air brakes is the use of highly pressurized brake fluid to apply disc foundation brakes. Technician B says that a more significant advantage for hydraulic brakes over air brakes is the use of low pressurized brake fluid to apply disc foundation brakes. Who is correct?

• Technician A

• Technician B

• Both Technician A and Technician B

• Neither Technician A nor Technician B

__________ data input from other control system modules to the full power hydraulic brake system control unit can add new features and enhance braking effectiveness.

• CAN

• WAN

• LAN

• Inter-network

A(n) ________ by Navistar is used by Class 4-7 vehicles, including Freightliner models.

• Full power brake system

• Hydraulically assisted braking system

• Surge braking system

• Electric trailer brake system

When discussing brake-by-wire technologies, Technician A says that the fixed piston-type caliper uses either an electric actuator or hydraulic fluid to apply and release the parking brake cable. Technician B says that the fixed piston-type caliper uses high-speed actuators to apply and release the parking brake cable. Who is correct?

• Technician A

• Technician B

• Both Technician A and Technician B

• Neither Technician A nor Technician B

Which of these hold true about master cylinder operation?

• Brake fluid creates a solid hydraulic link that causes backward movement of the secondary piston.

• The master cylinder pistons have seals at each end called cups.

• Brake fluid for the brake application is supplied to the cavities surrounding the master cylinder pistons by the front calipers.

• A second set of ports called the equalization ports allow brake fluid in front of the pistons.

When discussing conventional hydraulic braking systems; Technician A says that pushing the primary piston forward pressurizes brake fluid between both cups of the primary piston. Technician B says that pushing the secondary piston forward pressurizes brake fluid between both cups of the primary piston. Who is correct?

• Technician A

• Technician B

• Both Technician A and Technician B

• Neither Technician A nor Technician B

Which of these best describes hydrophilic?

• The fluid does not absorb moisture.

• The ability of the fluid to absorb water

• The ability of the fluid to absorb moisture

• The ability of the fluid to absorb air

A typical flex line construction uses a Teflon inner seal layer protected by __________ and reinforced with braided steel mesh to resist swelling during brake applications.

• Kevlar

• Nylon

• Dyneema

• Spectra

Brake ________ are used to pull the brake shoes back to resting position away from the brake drums when the brakes are released.

• Springs

• Hoses

• Calipers

• Pads

Technician A says that the inlet line and outlet line from the metering valve should be disconnected while testing the metering valves. Technician B says the outlet line from the metering valve should be disconnected while testing the metering valves. Who is correct?

• Technician A

• Technician B

• Both Technician A and Technician B

• Neither Technician A nor Technician B