216.—The Repair of Multi-plate Clutches, with Particular Reference to the Lancia.
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Clutch trouble is always a nuisance, as it usually means sending the vehicle in for repairs, thus waste ing time and money. In the case of certain foreignbuilt vehicles, such as the Lancia, many repairers are not very / well acquainted with the procedure to follow if clutch trouble is-experienced. Like thetbrakes, the clutch is often open to abuse, and a careless driver may quickly wear his Clutch as easily as he can make ribbons of his brake linings. When clutch trouble does occur, it is as well
to act at once ; any delay may cause further trouble and cost more in proportion. On taking down the clutch, the friction linings may be found to be worn to varying degrees and the outer plates warped or broken. 'Very little can be done with these plates except by an expert, who may be able to tap them back into shape, when they will once more be serviceable, so long as the tongues connecting with the clutch casting are not broken. The internal plate shown in the accompanying illustration is that of the Lancia 25 h.p. Z-type engine fitted to •15-cwt. vehicles. It is faced with friction material, which, of course, wears down in time.
If the friction surfaces for the plates are worn down to, say, 1-16 in., it will be quite possible to strip some of these from certain plates and re-rivet them on to the remaining plates two at a time thus bringing half the plates up to the required thickness, always remembering that it is as well to strip those plates of which the tongues are twisted or broken, provided the friction surface is in good condition although worn
n44 There are nine plates, each plate carrying a friction surface at each side. Assuming that the whole of the nine plates are found to be defective and that five of them are sound so far as the centres are concerned, it may be possible to pack up these five with the liners from the scrapped plates, thus saving something like £3 on this one repair. Should there be insufficient liners to pack up the good plates, it is quite an easy matter to purchase the liners cut to size from any well-known manufacturer at less than half the cost charged by the makers of the vehicles, and in this way a total saving of as much as £5 can often be effected.
217.—The Spring Chairs on the Leyland.
With reference to our Hint on Maintenance No. 193, in which it was pointed out that careful attention should be paid to the floating bush used in each of the spring chairs on the rear axle of the wormdriven model, the manufacturers have drawn our attention to the fact that there is no doubt that the rather inaccessible position of the grease cup on each chair has something to do with this matter, as drivers are occasionally inclined to neglect the replenishment of these cups. The problem of distributing lubricant uniformly in the case of hearings having a. large diameter and in which the rotary movement is slight is not an easy one. The makers have, therefore, made it a practice to lea.ve each of these bushes a very free fit both on the axle tube and in the spring chair, so that in the event of the bush becoming dry no serious trouble should result.
In the case quoted, it would appear that the bush fitted may have been too good a fit in the first instance. Of course, it is not known whether the bush in question was one of the Leyland Co.'s own make or a replacement fitted by the owner.
218.—The Care of Wire Ropes and Winding Drums.
The use of wire ropes is increasing rapidly on many types of commercial motor vehicles. They are used on almostall steam tractors and traction engines as well as for many types of tipping gear and other loading and unloading devices. It is, therefore, important that the concerned with running vehicles fitted with these ropes should know how to make the most of them.
Lubrication is one of the most important points in this connection. A well lubricated rope will last twice as long as one that is neglected. During, the process of making, wire ropes are saturated with suitable lubricant, but it rests with the user to see that as this lubricant is used up it is replaced. Any oil or grease which is heavy in body, contains no acid or alkali—i.e., is chemically neutral—and which will not gum or cause oxidization, is suitable No filling should be present' in the oil, as then it is likely to dry and flake off, and the hest method to apply it is by means of a brush. The connections at the ends of the ropes shouldbe examined at short intervals, and any defects promptly corrected. Wire ropes passing over pulleys are unduly stressed if the diameter of the puller is less than 19 times the diameter of the rope. The same remarks apply to the use of steel ropes on steam wagon capstans.
The pulleys may be lubricated periodically by pouring a little hot coal tar into the grooves. When fitting new ropes, it should be remembered that they can easily be damaged by careless handling, and a kink will not straighten out with-a powerful pull, although it may cause a break at the point where it occurs. Ropes supplied in coils should be un wound by rolling the coil along the ground like a
If a new rope is of a different size from the old one, it is advisable to re-turn any grooves in the drums, pulleys, or capstans, otherwise the wear will be excessive. So far as possible, loads should never be applied suddenly. Any excessive stretch denotes overloading. In the case of winding drums'fitted to the axle, as in certain steam wagons, these drums should never be allowed to swing loose while the vehicle is travelling, as this causes unnecessary wear.