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).
Procedure for fitting standardised bakelite ball pads to address low-speed wobbles on Phantom III chassis.
| Identifier | ExFiles\Box 95\1\ scan0503 | |
| Date | 31th August 1938 | |
| 350 To Hd.{Mr Hayward/Mr Huddy} from Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} FOR DEPOT SHEET. Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}7/MH.{M. Huckerby}31.8.38. LOW SPEED WOBBLES - PH.III. The coefficient of friction between the ball pins and the bronze pads (G.83415, G.84934) now fitted to Ph.III cross steering tubes falls as the spherical surfaces of the pads become polished with use. The result is that the spring load has to be increased by packing up to restore the original friction setting of 3 1/2 lbs. The bronze pads attain a stable friction after a mileage of approximately 20,000 provided the surfaces have not been disturbed. We have recently standardised bakelite ball pads (G.85769, G.85772) as these give a much more stable friction load, and they will come on to production at the 100th. chassis in D series. We recommend the following procedure in the case of existing cars. (a) All chassis still fitted with the original unsplit upper ball pads G.83414 should have new bakelite pads fitted throughout as the opportunity arises. (b) All chassis having the split type of ball pad, G.84934, which have run less than 10,000 miles since the pads were fitted should have new bakelite pads fitted throughout. (c) All chassis with the split type of ball pad, G.84934, which have run more than 10,000 miles should not be disturbed apart from adjustment as necessary. When fitting bakelite ball pads the washer G.8770 should be used in place of G.84935. The ball pin and the bore of the housing adjacent to the upper ball pad should be lightly polished with emery cloth. The joint should be well primed with oil before fitting to the chassis. Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} | ||