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).
Oil leaks in the D.W.S. jacking system on the Phantom III and the proposed solution.
| Identifier | ExFiles\Box 139\1\ scan0157 | |
| Date | 30th May 1936 | |
| GRY{Shadwell Grylls} x1166 c. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} E/Lid.{A. J. Lidsey}2/HP.30.5.36. re D.W.S. Jacking System on Phantom III. With reference to the jack rams which have recently been rejected and returned to the makers because of oil leaks from the top caps, an investigation of the trouble has revealed that the leaks occur at this point only when the pressure in the system is considerably higher than that required to lift a fully laden car to the maximum height allowed by the jack rams. The system as arranged at present does not incorporate a release valve, so that it is possible to go on pumping up pressure in the system after the car has been raised to its fullest extent. We are arranging to incorporate a release valve in the system which will blow off at a pressure 50% in excess of that required to lift the car, and also we have instructed the makers to test all rams at a pressure 100% in excess of that required to lift the car. The maximum pressure required to lift the car is 1800 lbs/sq.in. so that the release valve will be arranged to blow off at 2700 lbs/sq.in. and all rams will be tested to be free from leaks at 3600 lbs/sq.in before delivery. In the meantime in order to prevent jacks from being returned to the makers as faulty, will you please arrange that the tests are carried out on chassis by pumping up to the maximum lift allowed by the jacks only. Any further pump operation only results in increasing the pressure in the system, and is bound to produce a leak somewhere if carried on long enough. E/Lid.{A. J. Lidsey} | ||