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).
Issues and suggested improvements for the rationalised brake system.
| Identifier | ExFiles\Box 152\2\ scan0269 | |
| Date | 4th November 1940 | |
| 1294 To Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/MHR.{M. H. Rigby} Rm{William Robotham - Chief Engineer}/MHR.{M. H. Rigby}8/ET.4.11.40. POSITION OF THE RATIONALISED BRAKE SYSTEM. The main items group themselves as follows:- 1. Servo. (a) Judders. (b) Groans and Water Ingress. (c) Oil Ingress. (d) Ease of fitting. (e) Cam levers. 2. Wear of Rear linings. 3. Clearances of pins and levers. 4. Handbrake. 5. Rear Equaliser. Taking these in order:- 1. Servo. (a) Judder can be removed by inserting "sponge" between the servo pressure plate and the brake pedal. At the moment this is being done by means of a special rod assembly between the pedal and the cam levers, incorporating a spring which is effective up to 6 lbs. pedal load for 35° cams, and about 30 lbs. for 30° cams. The latter could probably be reduced from 30 lbs. Stronger springs are required to act up to the same load, but to give less deflection and a minimum extra pedal travel. Further suggested experiments are:- I. To add some friction to the rear cross-shaft. If this were effective, it might help the rear lining wear by giving less rear brakes at light pedal loads, and it would not increase the sponge. II. The old type star springs are effective up to 6 lbs. pedal load, and were sufficient to make 30.G.VII a drivable car, but they were not good enough for the 30° cams. They could be tried on a 4.B.50 as well as experiment I., this car being the only one with us which judders with 35° cams. (b) Water ingress to the servo occurs at the centre of the spring plate, and is completely stopped by means of two concentric shields, except when the servo is completely immersed. A small chain is required to cope with the latter contingency. A rubber washer was stuck on one spring plate by the British Tyre & Rubber Co., but it came off almost immediately. | ||