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).
Complaints of rear damper knocks across various models and their potential causes.
| Identifier | ExFiles\Box 130\2\ scan0041 | |
| Date | 11th July 1936 | |
| S/T Back HOTEL DE FRANCE. CHATEAUROUX. Indre. France. GWH{George W. Hancock - Head Chateauroux}/4/JAB. 11th July 1936. To. c to. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Re. Complaints of Damper Knocks. During the last quarter, there has been 62 complaints of rear damper knocks, Phantom, 25 H.P., 25/30 H.P., & Bentleys. In all cases these knocks have been cured by fitting new bushes, both inner and outer, of the damper lever arm. A pair of new dampers sent direct from the Works to Paris and fitted to a Bentley, knocked equally as bad as the ones taken off. New bushes had to be fitted to fit the shafts before the knocks were cured. It is seldom a case of wear having taken place. The clearance is too great (especially of the inner bush). I am sending a sketch of the two lever arms fitted to our 15,000 milestest car 22.G.V. It will be seen that the inner shaft bearing is .004" undersize, of the O.S.R. damper lever. The reamering of the bushes in production does not allow for undersize of the shafts. It is therefore, very probable that 90% of the complaints of damper knocks is due to limits allowed on the shaft diameters. Having found this discrepancy on our own dampers, I am taking precautions to measure up further complaints that arise. I should be pleased if you could give me the results obtained with regard to the lubrication of brake shafts, also petrol indicator leakage. ---------- G.W.H. | ||