BMW E32 brake accumulator and hydraulic brake booster

Probably. On 750 models the booster is hydraulic, and its pressure accumulator does not hold pressure. The assist is missing until the pump builds the pressure back up. A leaking master cylinder is another possible cause.

1. Press the brake pedal until it is hard and there is no assist left. 2. Remove the lines and the old accumulator. The accumulator's two 13 mm nuts can be reached once the alternator cooling duct and the fog light have been removed first. 3. Fit the new accumulator and fill the booster's oil reservoir. 4. Start the engine, turn the steering wheel and pump the brake. Finally, check the connections for leaks. Brakes are a safety item, so the job can be left to a workshop.

Not always. For example, the hydraulic connection on a Febi accumulator is different, so the fitting and bracket must be replaced or adapted. An intact used accumulator from a scrapyard is a cheap alternative.