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).
Issues with fierce brakes, brake squeaks, and front axle control on Bentley vehicles.
| Identifier | ExFiles\Box 82\4\ scan0028 | |
| Date | 26th November 1934 | |
| - 2 - Continued:- We think this feature calls for improvement as there were thirty eight complaints of fierce brakes during the last quarter, most of which were cured by increasing the swinging arm poundage. We notice that the front brake pull-off springs on the Bentley are considerably weaker than the 20/25 HP., and this means that the limit of friction on the swinging arm of the Bentley servo has to be lower to avoid sticking of the front brakes. We suggest that stronger front brake pull-off springs would enable the swinging arm friction to be increased with more consistent results and less tendency to thumping. 4. SEIZURE OF FRONT BRAKE TOGGLE SHAFT. Kingsbury report two cases of seizure of the outer bearing of the small toggle shaft at the top of the brake carrier plate. This bearing is unlubricated and it would appear that a little more initial clearance is desirable. Stronger pull off springs would assist this also. 5. BRAKE SQUEAKS. There is an increasing tendency to front brake squeaks on Bentley cars. No adjustment of the auxiliary shoe seems to have any effect and the only cure is to re-line the auxiliary shoes. Kingsbury point out that there is a considerable gap between the liner and the shoe, and they consider that this makes the brakes more susceptible to squeaks. We believe this gap, which is in the region of .010" to .015", is the result of machine rivetting, and we shall be glad to have your views as to whether this feature is likely to cause a pre-disposition to squeaks. 6. FRONT AXLE CONTROL. There have been several instances of poor lubrication of the front axle control member, causing creaks etc. The present metering value is ZT.2 and you may possibly consider increasing this to ZT.3. It has also been demonstrated that there is a possibility that the clearances between the various parts comprising the upper ball joint are too small to permit of adequate adjustment, and this may also result in the oil supply being cut off, due to the adjusting screw -contd- | ||