Hydrolastic

From Wikipedia, the free encyclopedia

Hydrolastic is a type of space-efficient automotive suspension system used in many cars produced by British Motor Corporation (BMC) and its successor companies.

Invented by famous British rubber engineer Alex Moulton, and first used on the 1962 BMC project ADO16 under designer Alec Issigonis (of Mini fame), later to be launched as the Morris 1100.^[1]

Contents 1 Description 2 Influences 3 Cars 4 Evolution 5 Notes

[edit] Description

The system replaces the separate springs and dampers of a conventional suspension system with integrated, space efficient, fluid filled, displacer units, which are interconnected between the front and rear wheels on each side of the vehicle.

Each displacer unit contains a rubber spring, and damping is achieved by the displaced fluid passing through rubber valves. The displaced fluid passes to the displacer of the paired wheel, thus providing a dynamic interaction between front and rear wheels.

The system was not popular with home mechanics, as it had to be re-pressurized after a chassis or subframe replacement. Even welding the sub-frame to repair rust damage typically required the system to be drained. The only way to re-pressurize was to pay a properly equipped mechanic, usually at a BMC dealer. Inevitably the charge for this service was higher than many cared to pay.

[edit] Influences

Jon Pressnell suggests in his book that the hydropneumatic suspension of the Citroën DS motivated Issigonis and Moulton, who were at the time of the launch of the DS working on a rubber and fluid suspension system themselves. Pressnell also suggests that the complexity of the Citroën system encouraged Moulton to develop a much simpler system.^[2]

[edit] Cars

Cars using the Hydrolastic suspension system:

• BMC 1100
• Mini (from 1964 to 1971)
• Austin 1800
• Austin Maxi
• Austin 3-Litre

[edit] Evolution

The Hydragas system was a development of this system.

[edit] Notes