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).
Phantom III brake issues, including seizing bearings and a push rod design flaw, and proposing modifications.
| Identifier | ExFiles\Box 92\4\ scan0137 | |
| Date | 28th January 1936 | |
| Y306 Memo from E.{Mr Elliott - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} CTRY - AFM{Anthony F. Martindale} re Phantom III Brakes. Referring to memo Sg.{Arthur F. Sidgreaves - MD}4/E.27.1.36, we have discussed this matter very thoroughly with Fraser, and also with Rm.{William Robotham - Chief Engineer} and it is apparent that the original trouble arises with the seizing up of the needle roller bearings on the bell crank levers on the axle, due to rust or the ingress of dirt. As a result of our previous experience with these bearings we went over to using Oilite bushes as shown on our scheme N.Sch.4653 issued 4.10.35. Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} also developed some protection in the form of felt washers for these needle bearings, for which a scheme N.Sch.4648 was issued on 4.1.36 as an alternative to the Oilite bushes. N.Sch.4648 was arranged to avoid end thrust on the felt washers. 35-EX was not fitted with either of these schemes. It is further apparent that when the bell crank lever sticks this leads to the external hand adjustment being manipulated so that the brake push rod falls out of position, rendering the brake ineffective. I was not personally aware until comparatively recently that the push rod on this brake gear could drop out of position, and that there were no features to retain it. As soon as this possibility became plain to me I had an instruction issued incorporating retaining rings, on the 4th of this month - N.Sch.4718, and these have now been demonstrated to retain the rod satisfactorily. These rings are applicable to the existing mechanism by machining suitable grooves in the levers and there is no doubt that we ought to alter every Phantom III car at the earliest possible moment. Another feature that we found on stripping the axle was that the hand brake shoes had been burnt out, and as we could find no evidence of the hand brake lever being left on this may have been caused by the needle roller bearings again on the bell crank operating the hand brake shoes suffering in a similar way to those on the foot brake. In addition to the retaining rings on the push rod levers we should also add to every Phantom III car either the Oilite bell crank bearings mentioned above or the protected needle bearings. Personally I think the Oilite bearing should be used. E.{Mr Elliott - Chief Engineer} | ||