The Rolls-Royce Silver Shadow and Bentley T Series motor cars are equipped with a power braking system and an automatic height control system, both of which utilise the same hydraulic fluid (RR363), and employ similar power sources. The two systems are, to some extent, integrated and various components used in each system are common. Both systems are entirely new, thus different servicing procedures and operations are involved.


The two pumps located on top of the engine are the heart of the whole system, delivering fluid at high pressure to the whole system. They are operated by the engine’s camshaft to guarantee high pressure to all the parts involved. The fluid is then pump to two accumulators, creating a dual system in order to possess a separate brake system. Each accumulator is compose of two parts; the upper part which is the valve accumulator and the lower part which is the accumulator sphere.

The accumulator valve consists of two internal valves that control the flow of the fluid. The first one remains open until the right pressure has been reached, if the pressure gets too high then the second one opens to alleviate the system by returning fluid to the reservoir. The accumulator is divided in two parts by a diaphragm, the lower compartment is filled with pressurised  nitrogen and the upper compartment where high pressurised fluid pushes down on the membrane. The accumulators provide 50 more brake pedal usage with the engine off before losing their pressure.

The system is filled with Castrol RR363 fluid. This fluid is specially developed for this system. It has lubricating abilities in order to keep running the moving parts. It is not allowed under any circumstances to replace the fluid by other fluids. All cars from 1980 and cars from chassis number 50001 (1979) are provided with a system that needs mineral fluid. This system can be recognised by the green labels that are stuck on several hydraulic components. The two kinds of fluid may never be interchanged or mixed.


The brake system is a triple system for the first models consisting of two high pressure systems and a low pressure system driven by the master cylinder. These three system are independent between them but all work simultaneously.

The two high pressure systems are link to the two hydraulic pumps while the master cylinder provides pressure when the brake pedal is pushed down by operating 4 of the 16 brake pistons on the calipers. The master cylinder is directly connected to the reservoir and is a back-up system in case the other two hydraulic systems fail. Between the master cylinder and the rear brake calipers a brake pressure limiting valve is present to prevent the brakes from locking up during an emergency stop.


The master cylinder is discontinued on the Silver Shadow II, making the brake system a dual system.



Early models had a height control for both the front and rear wheels but in 1969 the front height control was eliminated leaving only the rear one. Although, owners could get it fit if they wished so during any service turn-out.

This system constitutes the second high pressure system present in the vehicle therefore it uses the rear compartment of the reservoir, one of the pumps and one of the accumulators. The unique components present in this system are the electro-magnetic solenoid valve together with the restrictor valves control the height control valve, which together with the ram valves regulate the height of the car.

All designs provided by Rob Wilde.