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).
Dangerous 'servo jagger and grab' braking issue on chassis 21-TC and the need for further investigation.
| Identifier | ExFiles\Box 67\1\ scan0037 | |
| Date | 23th June 1926 | |
| Mx.{John H Maddocks - Chief Proving Officer} SFF. c. Hs.{Lord Ernest Hives - Chair} V8370 8PH 14 JUN 1926 RECEIVED EP{G. Eric Platford - Chief Quality Engineer}2/H23.6.26. re. Servo Jagger and Grab. I recently received a complaint from London that Chassis 21-TC. had been tried by CWB during the week-end. He complains that the brakes developed a servo jagger,and considered that the condition of the car in this state was dangerous, and that if the brakes were applied with anything but the greatest care and delicacy at any speed above 45 m.p.h. the servo jagger was so bad as to cause the efficiency of the brakes to be reduced by 50%. I advised him,first of all, to tackle the servo mechanism,to make sure the guide pins and movement of the cam mechanism generally were all in order and working smoothly. I have now received a report that this examination was made by 'N' and it was found that the moving plate had been sticking on the pegs. This having been put right, I understand the servo is now satisfactory. I bring this to your attention,however, as this is a point which we are continually tackling with cars on test, and I have turned a number of chassis down for the same trouble on which this feature has had to be tackled. As a matter of fact, Sales are now pressing for the rubber scheme modification to be fitted to cars which are faulty in this respect, and it is of vital importance that we should make quite sure the servo mechanism is correct as regards the features mentioned above. It would appear that some definite investigation is required in the construction of these features to make sure that the movement and freedom of these pins is correct and also other parts of the servo mechanism, as although this chassis gave trouble on test, the above points were attended to and I finally passed it, although the brakes were not entirely free from servo jagger,being assured that everything had been done that could be done to overcome this trouble. EP.{G. Eric Platford - Chief Quality Engineer} | ||