Brakes : Their Maintenance and Design.
Page 27
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The Editor, THE COMMERCIAL MOTOR.
[2410] Sir,---The letters on this subject, which have appeared in The Commercial Motor, are Interesting and it is quite time that the users were beginning to express their opinions on the matter, for it is a fact that some brakes have no design, whilst others cannot be maintained in an efficient condition.
Internal-expanding brakes are a delusion. The retarding effect at the wheels is entirely out of proportion to the man-power applied at the other end. The same power applied to a properly designed band brake would stop a train. No rear wheel running on plain bearings can have brakes in a perfectly efficient condition without constant and costly renewal of rear-wheel bushes. Rear wheels should be fitted with roller bearings. I have some that have run 123,090 miles, and I have not seen the bearings yet.
"0.8." (letter No. 2399) is right and " C.M.L." (letter No. 2402) is wrong. All brake drums wear, and this leaves two ridges, one at the edge and one in the centre, which are the heart-break of all who have to keep brakes up to the satisfaction of the other fellows Reboring Is, as " C.M.L." suggests, difficult and expensive, and when one remarks on the quality of the job, one is apt to get the reply, " Oh I sure it'll grip the better." Fortunately, I have overcome the ridge difficulty in a simple and efficient manner and hope shortly to send a contribution to one of your other pages on this subject.
" C.M.L." in/ paragraph 3 says, " We should Insist on a thorough demonstration." In paragraph 5 he says, "There are very few cases where the manufacturer would fail." Quite so, the failure comes a year after, when you are half-way down the hill or when the old lady steps off the footpath. The fact remains that the ordinary internal-expanding brake is a failure because it possesses no grip, and the diameter of the drum is too small for pure friction to be sufficient to control a heavy bus or lorry. I prefer fibrous lining at all times, and may say that I was fitting Ferodo no less than 23 years ago when working on a bus service with a 40-mile straight through route.
"U.S." should not lie on his back and oil his eyes. Let him obtain a small paint brush, a tin can and some old engine oil; he can then oil all his brake pins in a few minutes.—Yours faithfully, Londonderry.