MAKING BEST USE OF THE FORD.
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Valuable Advice on Every Phase of Ford Transport which will Appeal to the Owner, Driver and Repairer.
449.—Avoiding Back-lash in the Rear Axle,
A point which should be noted in connection, with the rear axle of the 1-ton Ford is the development of play in the drive shaft. Upon the first gear being engaged the vehicle does not move until the back-lash has been taken up, and instead of the vehicle moving away smoothly, as it should do, the movement Is commenced with a jerk, imposing severe and unfair stresses upon the transmission and upon the keyways, etc., in the axle itself.
To remedy this, remove the cap of the axle housing, and, inside this, the driveshaft nut, together with the washer, thrust bearings and plates on each side of it. Packing washers can now be inserted. They should be of mild steel, not less than 21 ins, in diameter and having a hole 11 ins, diameter therein. Sufficient washers should be inserted to make up ,a thickness by which all backlash is taken up by the drive shaft, and the thrust bearing and plates then assembled. The rear thrust plate should lie not less than 11,7 in. inside the axle casing.
When this has been done, do not omit to pack the thrust bearing with either thick gear oil or grease, as this part of the axle depends for its lubrication upon the oil picked up by the worm wheel, and as the vehicle would have to run some distance before this would take place effectively, serious harm might result if the bearing be not lubricated at the commencement.
The whole operation should be carried out after the vehicle has been running for some time, so that all the parts are warm and expanded to their maximum extent.
450.—Securing Piston Align ment.
After remetalling and scraping in a set of Ford big-ends, a mechanic is sometimes faced with the problem of making these perfectly parallel with the cylinder bores, and as there is a detachable head he cannot try them with his square, straight-edge or level, and trusting to luck will probably result in an objectionable knock due to bad alignment.
The difficulty can be overcome by the
use of a long piece of steel turned to the diameter of the big-ends and held in the vice, being adjusted perfectly horizontal by employing a spirit-level. The connecting-rod can be mounted on this shaft with Its piston already fitted, and the spirit-level laid on the piston head parallel with the bar. If the bubble be not central the 'rod is out of alignment
and must he set. "
451.—Testing for Generator • Faults.
Whilst a complete equipment is necessary for the testing and repair of dynamos, a good deal of work can be performed in connection with the Ford generator.
A simple and cheap testing set can be made from Ford parts, using a sixvolt battery as the source of power, the rest' of the set consisting of a headlamp bulb and socket, two pieces of brass or
steel rod filed to points and a yard or so of flex.
After performing the ordinary maintenance work, such as sanding-in the brushes, cleaning, etc., if the dynamo still refuses to function, a test set proves helpful in discovering the trouble. • If the generator has been running with the battery disconnected and excessive current is being developed through a wrong setting of the third brush, the trouble will probably be duo to burnt-out armature windings or field coils. Burnt-out windings cause a ground or short circuit, and, in the former ca, can be detected by touching one point of the test set to a commutator bar and the other to the shaft. If the current be running tb ground the lamp will light.
Tests for short circuits are beyond the scope of this article, but a bad burn-out is easily found by the chaired insulation.
Field windings are tested for grounds by touching one pbint to the field wire and the other to the generator housing. Again the lamp will light if a ground exists. Remove the fields and examine the coils. Probably the ground is at the pole piece, and retaping and shellacking may effect a cure.
A low-reading ammeter is necessary to detect a short, but a fair idea of the condition of the fields can be obtained by putting a six-volt gas-filled bulb in the test set and "touching a point to each of the field leads. If in order the lamp will light with reduced brilliance, but a bad short is indicated by the lamp refusing to glow.
Bad insulation of the brush ring is a common cause of generator failure, but when working with a six-volt battery the potential is not sufficient to light the
test lamp. If a 110-volt or 220-volt circuit be used a 10-amp. fuse in series is necessary. Examination of the brush ring may reveal cracks in the insulating material, and remember that the slightest crack here is liable to render the generator inoperative. The positive and third-brush holders are both insulated, the negative being grounded.
Incidentally, most of the trouble with the brush ring is caused by trying to move the third-brush holder without slackening the locknnt.
When reassembling, see that the four small screws holding the brush ring to the end cover do not touch the commutator, which occasionally happens and causes a ground. The cut-out securing screws, if too long, can penetrate to the fields, so watch that point. Examine the insulOtion of the main terminal and renew it if faulty, avoiding excessive tightening of the locknut. As -a matter of fact, if tightened sufficiently to prevent it moving. that is all that is necessary.
After reassembly, the dynamo can be tested by connecting a six-volt lamp to it, one lead to the main terminal and the other to earth. A piece of strong string wound round the drive end of the dynamo and pulled sharply will rotate it sufficiently to light the lamp if the dynamo be working satisfactorily.