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).
Technical report on brake system performance, issues, and recommended modifications.
| Identifier | ExFiles\Box 108\3\ scan0237 | |
| Date | 9th May 1938 | |
| -12- The brakes were generally satisfactory. Servo judders occurred due to the star springs binding on the servo spindle. A modified type of star spring with a clip location and increased diameter centre hole was found effective in preventing binding and is recommended. Various alterations to rod lengths and increase in clearance in the slots in the cruciform were found necessary and should receive attention for production. The front brake linings wore out before the end of the mileage. They lasted approximately twice as long as those on 22.G.VI in France, which represented the present standard 25/30. Half the adjustment was used up on the rears. The standard of freedom from squeaks was good with no front tipping shoes and the rear tipping shoes set solid. Front wheel skids on wet roads and diving were experienced. The front brakes were over-heated rather easily, and flats formed on the front tyres. Examination of the front brake drums showed black patches at intervals round the friction surfaces. These are associated with over-heating. The surface also showed small longitudinal cracks all the way round which increased during the running, and several ran right across. The m.495 lever which reduced the front braking by 10% was fitted to reduce this action, ran 8,000 miles and has been standardised. The same symptoms were present to a very small degree on the rear drums. Grease had escaped from the nearside rear hub on to the brake mechanism. This was due to the outer race of the inner bearing turning in the hub and wearing the fibre washer sothat it no longer formed a seal. This is a question of machining limits. The front brake connection on the servo lever fouled the gear box cross member when the brakes came on unless they were fully adjusted up. The crossmember was cut away to clear. This should be modified for production. The hand brake ratchet stuck on several occasions. | ||