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).
Brake performance issues and modifications for a Bentley III, addressing spongy feel, violent diving, and rear brake geometry errors.
| Identifier | ExFiles\Box 98\3\ scan0015 | |
| Date | 4th March 1938 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} c. DA.{Bernard Day - Chassis Design} c. Hdy.{William Hardy} c. HPS.{Horace Percy Smith - Experimental Factory Mgr} 2006 Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}13/MH.{M. Huckerby}4.3.38. 406- BENTLEY III BRAKES. On first trying the car the brakes appeared to be spongy. This was largely due to star springs in the servo. We have removed the star springs, replaced them with plain washers, and added a 10 lb. "pull on" spring to the rear end of the servo pick up rod to rear brakes, where it passes through the frame cross. If the spring is stronger than 10 lbs. it holds the rear brakes on. We have not been able to get servo judders like this. The brakes are very effective. We want to run all Bentley III's without star springs, and would like an official scheme for the "pull on" spring. The car generally pulls quite straight on hard braking but the steering wheel is liable to be wrenched out of the driver's hands by an unexpected violent dive, which is very unpleasant. The large out-of-centre-point may be responsible for this, because on straightening the wheels again they remain straight. There is a bad geometry error in the rear brake ropes which causes the hand brake lever to "pump" violently as the car bounces on its soft springs, as it comes to rest. This is chiefly due to rear axle twist. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} | ||