Automobile & Light Truck Certification Test A5 BrakesPower Assist Unit Diagnosis and RepairEasy
Which of the following components is responsible for maintaining a reserve of hydraulic pressure for brake assist in a hydro-boost system, even after the engine has been shut off?
- AProportioning valve.
- BAccumulator.
- CMaster cylinder.
- DPower steering pump.
Show answer & explanationAnswer & explanation
Correct answer: B. Accumulator.
The accumulator in a hydro-boost system is a spring-loaded or gas-charged component that stores hydraulic pressure. This stored pressure allows for several power-assisted brake applications even if the engine (and thus the power steering pump) is not running.
Why the other options are wrong
- A. The proportioning valve balances brake pressure between front and rear wheels, not storing assist pressure.
- C. The master cylinder converts pedal force into hydraulic pressure for the brakes, but doesn't store assist pressure.
- D. The power steering pump generates the pressure, but doesn't store it for post-engine-off use.
Hydro-Boost Accumulator
A component in a hydro-boost brake system that stores hydraulic pressure, allowing for power-assisted braking after the engine is turned off.
- Stores hydraulic pressure.
- Provides reserve brake assist.
- Typically spring-loaded or gas-charged.
Memory trick: The accumulator's like a battery, saving power for when the engine's off, you see!