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).
Summary of tests carried out to overcome squeaks from front brakes fitted to a 12-EX model.
| Identifier | WestWitteringFiles\P\October1926-November1926\ Scan075 | |
| Date | 25th October 1926 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} DA.{Bernard Day - Chassis Design} ORIGINAL X7420 SUMMARY OF TESTS CARRIED OUT TO OVERCOME SQUEAKS FROM FRONT BRAKES FITTED TO 12-EX. We have been able to damp out all normal squeaks by fitting a damper band round the drum. We found that this band should be the full width of the drum to give maximum efficiency in overcoming the squeaks. We are of the opinion that with the present design of brakes, the damping of the brake drum is necessary to avoid complaints of squeaks. There are excessive squeaks that the damping does not entirely cure, but when the brakes have reached this stage, the shoes are in a very dry condition and generally nearly worn out. In investigating the squeaks we have found in all cases that the squeak occurs when the bedding of the shoe shows the most load on the heel, and by removing the load off the heel on to the toe portion we have definitely cured the squeak. We have been able to produce squeaks and cure them by making the bedding on the toe and heel respectively. Our theory of this is that when the heel has the most load, a condition arises whereby the reduced load on the toe is sufficient to cause the drum to vibrate, and in 90% of the squeaks we find it is the wrapping shoe which creates the vibrations. We have found that if the non-wrapping shoe has the most load on the heel, with a certain load it will still cause the vibrations. contd :- | ||