F - Electric Brake Fundamentals and Service Flashcards
In an electric brake wheel assembly, which components are similar to those used in hydraulic drum brake systems?
Brake shoes, return springs and associated hardware.
Brake drum friction surface provides a similar function.
Backing plate and anchor assembly.
In an electric brake wheel assembly, which components are unique to the electric brake system?
Electromagnets, actuating lever and block assembly.
Brake drum inner machined surface is special.
What is the function of the electric brake controller?
Used to synchronize or balance braking action of tow vehicle and trailer. Can be manually operated as well as by action of brake pedal.
True or False: In an emergency situation the electric trailer brakes will be able to provide the total braking requirements needed by the truck and trailer combination.
False; The trailer brakes will never be able to provide total braking required by the combined tow vehicle and trailer.
When you are using an ammeter to check the trailer brakes, a high amperage draw reading could indicate:
A short circuit in the electromagnet.
Explain the function of the auxiliary breakaway battery located on the trailer.
When a trailer breaks free of the tow vehicle, the electrical connection to the truck battery is lost. The auxiliary breakaway battery provides full available battery power to the trailer brakes. Maximum braking should occur.
Provide reasons why electric brake systems may develop electrical problems between service intervals.
Looseness of terminals and connectors over time.
Road salt or water contamination and corrosion of electrical components and connections.
Broken conductors and damaged trailer connectors.
Corrosion at truck battery terminals and cables.
Reduction of alternator output.
Chafed and damaged conductors, insulation worn.
True or False: When testing an electric brake wheel assembly with a voltmeter, you notice a high voltage when the controller level is moved very slightly. This indicates a normal condition.
False; Small movement should cause small voltage increase.
If you were testing the relationship between controller lever movement and wheel brake voltages, explain: When a low voltage reading would be normal. A high voltage reading would be normal. The highest voltage reading would be expected.
Small lever movement - low voltage to brake
Large lever movement - higher voltage to brake
Full lever movement - maximum voltage to brake
True or False: The truck brakes and the trailer brakes are synchronized by adjusting the brake controller during a series of road tests.
True.
