TRANSMISSION TROUBLES.
Page 27
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Difficulties Met and Overcame by Our Driver and Mechanic Readers.
ALONDON driver—" E.S.T.," ul West Ham—tells us that he has had a certain amountof trouble with a propeller-shaft coupling at the gearbox And 0 the earda.n shaft of his Pierce-Arrow cha.ssis, owing to the inadequacy of the locking arrangement for one of the pins. . There are two methods adopted by the makers for this purpose; depending upon the date of the chassis: In one, spring clips, eeCured by setscrews to the body of the universal joint, cover the ends of the pin and prevent its endwise movement. In the second the pin has a. collar at one end and is secured by a loose collar at the other, which is retained by a setscrew, as shown in the accompanying sketch. A€ one effect of vibration, these screws shake out, and the mein pin comes away from the joint. Other readers who have had this trouble may be interested to learn that it can be cured. entirely if they will drill a el-in. hole right. through the centre of the pin, procure a large-diameter washer, big enough to cover the pin and bear on the ends of the bearing for that pin, make a -ken. bolt, which is a reasonably tight'. fit in the hole and long enough to accept the 'washer and a nut and split-pin, or nut and spring washer at the outer end. The arrangement is shown on the sketch.
In most eases the pin will be soft enough to drill, bue, if not, it mail easily be softened, 'drilled, and subsequently rehardened.
Gearbox trouble is the original cause of " A.G.B.," of Barming, near Maidatone. writing for the benefit of readers of this page. He states that, quite recently he was climbing a hill, driving a well-known make of chassis, and as he reached the top endeavoured to change from second into third speed. When, however, after, as he thought, engaging the new gear, he re-engaged the clutch he discovered that second speed was still in mesh. A careful examination of the various connections eventually disclosed the fact that the trouble Was due to a broken selector rod, and, hi order to get home, he had to arrange
for the boy who was with him to change gears by fiend thremgh the hand hole in the gearbox lid. On another occasion, again when hill
climbing, he was about to drop back into second speed, but found that he could not. move the gear lever past the neutralenotedi, acid had to slip right back into low gear in order to reach the top of the bill, when he stepped down and tried to discover the cause of the trouble. Apparently everything was in order, and he was just going to give up and telephone for a tow, when, feeling all round the various parts inside the gearbox, he found that there was something wrong with one of the long feather keys on the mainshaft. These keys are held in place by tapered pins driven through the key into the shaft. One of the pins had worked itself up and was preventing the sliding wheel from moving. After knocking this in again with the blunt end of a chisel no. further trouble was experienced.
" cif Bradford-on-Avon, tells us that he was recently called out to a subsidy model A-type Maudslay which had developed gearbox trouble. On removing the gearbox cover he discovered that the selector fork for the third and the top gear had broken, putting these two gears out of action. He first removed the broken piece of fork and attempted to drive home, using first and second speeds only, but discovered that this was likely to be productive of even more trouble, owing to the fact that the sliding gear, with which the broken fork should engage, was moving about in the box, damaging both its own teeth and those of other wheels with which it came in contact. The obvious thing to do was, of bourse, to fix the drifting gear so that it could not slide about, 'but this was not so easy as might be thought. "I had," he writes, "no clips of any kind in my tool-bag, but, still thinking on those lines, I was fortunate enough to discover that the diameter of the splined shaft was about the same as that of the lower hose-pipe on the engine. As the hose was already bound with stiff wire after the fashion recently described in The Commercial Motor, it was safe to remove the ordinary clips. These I fitted to the splined shaft, one on each side of the gearwheel, as shown in the accompanying sketch, fixing the third-speed gear permanently in engagement. This was good enough to enable me to .get home.
"Incidentally, a neutral position was achieved with this gearwheel fastened in the position shown, by holding the clutch disengaged by means of a block of wood between peelal and floorboard:"
The letter from " H.A.B.," of Rotherham, describing how to effect repairs to gearwheels, is interesting, in view of the short paragraph dealing with this particular matter which appeared on another page of The t'ornmerctal Motor recently. It should be added :that this letter was in our hands before that paragraph
appeared. He remarks that the most popular methods of replacing a broken tooth in a gearwheel are either the use of studs screwed into the rim of the wheel and filed to shape, or of pieces of metal dove-tailed into the rim. The first ie more simple as it involves only drilling the metal in the wheel. The second is more elaborate, as the wheel must be mounted in a shaper or Blotter, in order to cut a dove-tail groove in the rim. The piece which fits the groove also calls for accurate machine work.