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).
Issue where the Phantom III's front brakes engage when the car is jacked up, and a proposed solution.
| Identifier | ExFiles\Box 92\4\ scan0264 | |
| Date | 19th November 1936 | |
| To EY. Rm.{William Robotham - Chief Engineer} Copy to Mr. Der. Rm.{William Robotham - Chief Engineer} RMC/DMM. RAC/R.B. MARTINDALE LES } PLEASE DISCUSS WITH ME Phantom III Front Brakes coming on when car is jacked up. Sales have reported that on Phantom III production cars the front brakes still come on when the car is jacked up, in spite of the modifications which we instructed to the setting of the air dash pot and the removal of the stop on the idler lever on the frame extension. The complaint is that the wheels cannot be turned for washing, that the wheel cannot be spun when screwing up the wheel nut by means of the spanner, and that the front hub cannot be used for balancing the wheel. We have made fairly extensive tests on several production chassis in the Test Dept. and have found that to free the wheels, it is necessary to reduce the rebound at the buffer by .4" approximately, which represents approximately 3/8" at the wheel. This is a bare minimum and would not free the wheels sufficiently for balancing purposes due to most cars exhibiting a certain eccentricity of the brake drums. We are proposing as a cure, to reduce the rebound by the amount we specify, and to increase the brake shoe clearance by a half-turn of the adjuster which we estimate to be approximately 3 1/2 thou. at the centre of the shoe. As the cars are sent out now, the adjusting wing nut is screwed right back. It will be necessary, therefore, when setting the brake pull rod length, to have this adjustment wing nut one turn forward from its backward stop. It will be necessary when setting up the brakes and also in our instructions to owners, to tell them to adjust their brakes up as far as they will go and then to slack back one half-turn. With this arrangement the wheels will be always free. We are aware that the increased brake shoe clearance will rob us of some of our brake rod travel which we have recently been endeavouring to increase. It would | ||