Chassis Types.-Before discussing the points to be inspected nd the manner of making repairs when defects are found, it may e well to describe briefly some of the typical chassis constructions n order that the novice repairman may get an idea of the relaion of the parts in cars of conventional design. The side and lan views of a National four-cylinder chassis are shown at Fig. 39, all the important components being clearly indicated. This may be considered a good example of high grade car construction n which the power plant and change speed gearing are separate nits. As is apparent, the engine may be removed from the frame without disturbing the change speed gearset while the gear box may be taken out without requiring the removal of the engine. The general construction of this chassis is conventional and follows established automobile engineering practice. It has the virtue of aving the parts readily accessible so that repairs may be easily nade without disturbing other components except those that are to be worked upon.

The plan view at Fig. 340 shows a chassis of recent development produced by the Cadillac Company which is provided with an ight-cylinder V engine having the transmission gearing incorported as a unit with the engine crankcase. This construction is more accessible than the usual unit power plant is, owing to the design which permits of removing the transmission case from the engine base without disturbing the power plant. In all other respects his chassis follows conventional practice. The important parts are clearly shown and no difficulty should be experienced in identifying them on the actual chassis.

The repairman will be more often called upon to repair motor trucks in the future than he has been in the past on account of the increasing popularity of the heavy duty vehicle. The chassis construction in the main follows the design established in pleasure car practice, excepting for the use of much stronger parts and a tendency to use standard structural steel shapes for frames instead of the special pressed steel side members commonly found in pleasure car service. The average truck chassis will have a pronounced overhang over the front and rear axles in order to obtain a body of sufficient size without unduly increasing the wheel base. Gear

riven trucks do not differ materially in construction as far as relaion of parts is concerned from pleasure cars of the present-day ype. The worm drive and double reduction axles are rapidly aining favor and the conventional side chain drive construction o which most of the trucks have been built is gradually being isplaced by the more modern forms having a live axle instead of he fixed non-rotating member shown at Fig. 342. It will be renembered by those who have had automobile experience, dating a umber of years back, that many of the powerful pleasure cars Tere fitted with side chain driving systems. The power transmission ras to a jack shaft which was practically a live rear axle having prockets at the axle ends instead of wheels, and from that member o the rear wheels, which were revolved on a nonrotatable axle by Leans of driving chains. The process of taking down a motor truck chassis and the points to inspect for depreciation would not fer materially from that used in repairing a pleasure car assembly. Owing to the use of solid rubber tires, a motor truck is subjected to much more vibration than a pleasure car, and considerable more attention should be given to the running gear parts, as these may become loose much sooner than on the pleasure rar, where all of the load is carried by very resilient pneumatic tires.

No treatise on automobile repairing would be complete without showing details of the Ford model T automobile, which is the most widely used motor vehicle in the world. The reader's attention is directed to the very clear sectional view shown at Fig. 343 for an idea of the arrangement of parts on this universally used motor car. The various parts are clearly outlined and may be located by following the leader lines to their termination at the arrow point. The other end indicates the name of the component. The plan view at Fig. 344 gives an idea of the appearance when viewed from the top.

Dismantling a Chassis.-The various steps incidental to dismantling a motor car chassis to give all parts a thorough overhauling is shown at Fig. 345. The plan view showing the appearance of the chassis of a Locomobile car at A denotes the appearance after the body and fenders have been removed. It is always ad

visable to remove the body and the mud guards before any w is done upon the chassis, and in case of an extended overhaul much time can be saved by sending the body and guards to paint shop while work is being done on the chassis. This is sirable because the finish of the body is much more important t that of the chassis parts, and it takes more time for the pai to do an enduring painting job on the body than on the run gear. The next step is to remove the running boards and run board irons, if these members are fastened to the frame by b If the running board supporting members are riveted to the fr it is not necessary to remove these unless the frame side memb to be re-enforced. The wheels are removed from the front rear axles and the frame supported by special jacks. These m easily made by using substantial cast iron base plates about in diameter in which a piece of two-inch pipe is screwe sliding arm of cast iron made with either a cam or gib ke or having a strong set screw to keep it in place when it is the proper height, is adapted to move up and down the pip some cases holes are drilled through the pipe and a stop pi through it on which the supporting arm is allowed to rest. frame supports have the advantage of not interfering w removal of the various chassis components as they support weight directly under the frame sides instead of through dium of the axles and springs as the ordinary lifting ja Four of these stands are used, two on each side of the car.

The appearance of the chassis with the running boar wheels removed is shown at Fig. 345, B. The next step i move the radiator, the steering gear and the change spee controlling members. The clutch and brake pedal cross sha also be taken from the chassis at this time. This leaves the in the condition shown at C, Fig. 345. The next step is off the rear axle, including the propeller drive shaft, torqu ber and radius rods. The chassis then has the appearance After the removal of the change speed gearing the parts shown at E. The dashboard assembly and the engine are ne off the frame, which leaves the frame as shown at F. At only the front axle and rear springs are retained. Whe