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).
Modifications to the 4-wheel servo brake system to improve braking balance.
| Identifier | WestWitteringFiles\K\November1923\ Scan27 | |
| Date | 12th July 1923 | |
| R.R. 403A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} ORIGINAL. Expl. No. 9940 REF:- Hs{Lord Ernest Hives - Chair}1/LG10.11.23. EXPERIMENTAL REPORT. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to C.J. c. to Rg.{Mr Rowledge} c. to Da.{Bernard Day - Chassis Design} c. to EY. E.A.C-3 - 4-WHEEL BRAKES. In our previous report (Hs{Lord Ernest Hives - Chair}1/LG10.11.23) we mentioned that we were getting effective braking on the rear brakes but very little braking on the front. When we examined the operating mechanism we found that the servo brake was applied before the clearance in the front brakes was taken up, and also before the resistance of the pull-off springs was overcome. We therefore temporarily disconnected the pull-off springs on the front brakes and fixed an additional spring to operate against the pedal on the rod operating the servo brake. The effect of this was that there was no movement in the operation of the servo brake until we had taken up the clearance on the front brakes. With this modification we found that we got reasonable braking on all four wheels. On a greasy road, the front wheels were always locked before the rear. In applying a steady pressure on the brakes, one could feel the front taking affect first and the rear coming in when considerable pressure was put on. During these tests we got the impression that there was a considerable inertia effect on the servo brake. If the brake was applied suddenly when the car was travelling fast, the rear brakes were immediately locked, whereas, if a steady pressure was put on, it was much more difficult to lock them. We got the same brake jaggers on this car contd:- | ||