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).
The causes and characteristics of squeaking brakes on the 20 HP model.
| Identifier | ExFiles\Box 66\5\ scan0005 | |
| Date | 17th April 1925 | |
| H.R. 493a (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}1/LG17.4.25. X 8360 X4257 X4259 X8360 To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c.c. to CJ. BJ. c.c. to RG.{Mr Rowledge} L. c.c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} c.c. to Wor.{Arthur Wormald - General Works Manager} 20 HP. - SQUEAKING BRAKES. Experience shews that there are two kinds of squeaks which cause trouble on the 20 HP. brakes. One is a high note squeak - this is the one which is the cause of the majority of complaints, the other is a lower note which we term a groan. This low note only occurs at very slow car speeds. When the low note occurs it is possible to feel on the brake drum, the brake carrier, and the brake operating shaft a distinct vibration. When the high note squeak occurs, one cannot definitely feel any part vibrating. The high note squeak can be eliminated by effective dampers on the brake drum. The low note groan cannot be cured by dampers on the brake drum, but is reduced. Squeaks or groans never occur on a new car. It would appear that it is necessary for the brake lining and the drum to be in a certain condition to produce squeaks. Whenever the brakes are disturbed at all, the squeaks disappear for some time. This has often led us to believe that we had overcome the squeaks, but after a time they were as bad as ever. It requires only the slightest amount of lubrication to prevent squeaking. The amount of lubrication does not spoil the efficiency of the brakes. We have the impression that side-by-side brakes are the worst offenders for squeaking. The cars which are contd :- | ||