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 with brake friction linings, their temperature limits, and customer complaints about squeaks.
| Identifier | ExFiles\Box 141\1\ scan0202 | |
| Date | 30th October 1936 | |
| Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}10/MJ. -2- 30th. October, 1936. have come to the conclusion that no friction lining will stand repeated overheating. It is only satisfactory if it never exceeds 200°C., although occasional temperatures of 250°C. do not seem to hurt it much. But if it regularly reaches 300°C. (572°F.{Mr Friese}) it gives nothing but trouble. The friction coefficient may vary between .2 and .65 ( or even more than .65) and it will squeak. Now my problem is this: we have hundreds of cars on the road, and all their brakes give trouble through Ferodo failures diving, fierceness, fading, squeaks, and of these squeaks are the most numerous, about 700 complaints per annum on Bentley alone. I think a lining with a cold friction value of .3 may help. Have you such a lining? I can put up the servo power to compensate. The lining must not score the drums, and its "fade" characteristics must resemble F.B.A. As regards BZ. We fitted it as a last resort to a customer's car to cure squeaks, and he says it still squeaks. When you have digested this, you will see that we want - (1) A friction lining that does not score drums. (2) A friction lining that has a low friction value. I shall be glad to hear from you in due course. Yours very truly, For Rolls-Royce Ltd. | ||