Grand Marquis V8-351 5.8L (1982)
Hydraulic Brake Booster: Description and Operation
Hydro-boost II is a hydraulically operated power brake booster. The hydraulic brake booster consists of an open center spool valve and a hydraulic
cylinder combined into a single housing. The power steering pump provides the hydraulic fluid pressure to operate both the power brake booster and the
power steering gear.
A dual master cylinder is bolted to the brake booster and is operated by a pushrod projecting from the booster cylinder bore.
This system uses a compressed gas accumulator as a reserve system to store sufficient fluid under pressure to provide at least two brake applications if
fluid flow from the power steering pump is not available.
The booster is designed so that if a total absence of power assist occurs, the brakes can be applied manually, but somewhat greater pressure on the brake
pedal is required.
