From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Audible knock caused by hydraulic shock dampers.
| Identifier | ExFiles\Box 55\3\ Scan285 | |
| Date | 12th October 1926 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} C. to BJ. Wor.{Arthur Wormald - General Works Manager} C. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} X235 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG12.10.26. HYDRAULIC SHOCK DAMPERS. We have had a case of hydraulic shock dampers wearing sufficiently to cause an audible knock on the front of the car when negotiating a moderately bad road. We are surprised to find what a small amount of free movement occasions this knock. We have dismantled one of these dampers and cannot detect any appreciable wear in the links. There is a small amount of wear in the bearing of the lever arm. The knock was shewn up by fitting a pair of dampers that had done a considerable mileage to a car upon which all rattles had been suppressed. The oil in the dampers covered the piston but was below the bearing of the lever arm. We are carrying out tests with various oil levels and viscosities with a view to reducing the trouble. Hs{Lord Ernest Hives - Chair}/W. A.{Mr Adams} Robotham. | ||