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).
Letter clarifying the brake equalizer system and the procedure used to diagnose unequal brake lining wear.
| Identifier | ExFiles\Box 140\4\ scan0130 | |
| Date | 6th January 1938 | |
| 1181 9 January 6th.1938. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}3/AP. Your Ref. 1/NB.478 Messrs Gandy's Belt Manufacturing Co.Ltd., Seacombe, WALLASEY, CHESHIRE For the attention of Mr.G.Ikin Dear Sirs, We thank you for your letter of 5th inst., regarding the samples you are sending. You appear to be under a slight misapprehension both as regards the construction of our cars and the way we run them, and we would like to clear this up. There are 3 equalizers on the car, one between the front pair of brakes, one between the rear pair of brakes, and the third between front and rear brakes. The latter is so arranged that a predetermined ratio is maintained between front and rear brakes, not necessarily equal amounts. Thus on our cars it is just as impossible to apply widely differing loads to the pairs of shoes on each axle, as it would be if they were hydraulically operated, which means that if the linings wear at very different rates, then something is wrong with the lining, for instance, oil on one drum (there was no oil in any drum on the car in question.) You are quite wrong in assuming that unless we noticed diving of the car we took no action to check it, on the contrary, we immediately removed the drums, checked over all adjustments, inspected the linings and rebedded them. This not having the desired effect, we again removed the drums, and interchanged one shoe off each side (front axle only, rear axle trouble free.) After a few miles further driving the pull of each of the front brakes became equal and has remained so. Thus we confirmed our impression that the linings were gripping unequally. continued | ||