Vetting a Used Vehicle
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Part Two An Easily Followed Formula for Checking a Vehicle After .Road Test: Faults that May -Escape Detection By Edward Meeson,
M.I.R.T.E. IN making a static inspection of a used vehicle, the engine can be quickly disposed of. as its general running will already be known from the road test (see last week's issue). First ascertain that none of the manifold lugs or studs is broken, and that there are no water leaks from the block Of radiator. Detach the radiator cap. and note whether there are indications of oil on the surface of the water. If there are, the cylinder block may be cracked.
Next see that the radiator is firmly mounted and finally take note of the condition of the water hoses. If they feel thin it is possible that they will have to be renewed. When closing down the bonnet make sure that it fits properly and that its clamping-down arrangements are complete and sound.
See that the straps and brackets supporting the petrol tank have mat been allowed to work loose, for the tank itself may have become chafed, thereby weakening it at this point. Examine for weeps and leaks at the seams and drain plug.
Examine Wiring Badly frayed or oil-soaked wiring will have to be renewed, sothat the general condition of the wiring should be carefully checke-d.
, Other features to note in connection with the ignition and lighting are concerned with the extent. of the wear of the distributor-shaft bearings, headlamp reflectors, the battery-securing arrangements and the general conditionof the battery and cables.
Note the position of the ammeter needle while the engine is running and all the lights switched on. If the ammeter shows a slight discharge under these conditions, the dynamo output is fairly satisfactory.
The prospective purchaser should go carefully over the steering linkage. noting the degree of backlash and tracing it as far as possible. Whilst a certain amount of slackness in the steering is inevitable with a much-used vehicle, it should be the first care of the purchaser to check and renew those parts which indicate excessive wear.
It is important to stress the difference between loose ball-joints and loose drop-arms and steering arms. The joints are designed to be movable, whereas the others should be immov a22 able in relation to the shafts to which they are secured.
Faulty front-wheel alignment would probably have been brought to light during the road test, the vehicle showing a tendency to pull to one side. In the absence of special equipment, the condition of the tyres may provide a due as to whether or not the wheels are running true in relation to the chassis. If there are severe signs of scuffing. alignment is faulty.
The steering gearbox may be loose on the frame. If the box is not damaged, it is probably only a case of
tightening the securing bolts. Excessive wear in the steering gear itself may mean renewal if all the slack has
previously been taken up. Therefore, note whether there are shims remaining between the two members which normally provide for such adjustment. As these shims are usually of brass, • they can be seen by wiping away any accumulation of oil and dirt which may be obscuring the joint.
Examine the springs for any undue sag, as this may indicate broken leaves, which may be revealed after scraping the edges clean. Check that the centre bolt is not broken by trying a spanner
on the nut. Should there be little or no resistance to turning, it is more than probable that the bolt is broken or the thread stripped.
Spring shackles and pins can be tested for excessive wear by the use of a short crowbar in such a position that it is possible to produce relative movement between the parts. At the same time, a note should be made of the tightness or otherwise of the rivets uhich secure the shackle-bracket mountings.
Checking Loose Rivets
Tapping is as good a method as any of detecting loose rivets. Should it be necessary, loose rivets can be removed, the holes reamed out and high-tensilesteel bolts substituted.
Wheel bearings can be tested for slackness by jacking up the front axle and endeavouring to rock the wheels. This will also reveal any undue wear in the king-pins and bushes. This must be done carefully to ascertain whether the wheel bearings or the pins are worn, as it is easy to get the wrong impression.
In the case of the rear-wheel bearings, with a jack under the axle, a crowbar can be used under each wheel in turn: quite a small movement will indicate considerable wear. Before the jack is let down the general condition of the tyres can be assessed.
Do not be satisfied with a general look-round with the tyres on the ground. as serious defects may be hidden in that part of the tyre in contact with the ground.
It may be difficult to detect cracks in the chassis frame, but it is worth spending some time on such an inspection. The area most likely to be affected is that just to the rear of the cab, especially if the vehicle is a tipper.
If the universal joints are of the
flanged-coupling type, the coupling bolts should be carefully checked. If they become loose and are allowed to run in that condition, the bolt holes in the flanges will eventually elongate. Should this trouble have developed, the holes can be drilled and reamed oversize to take larger bolts.
Gearbox and shock-absorber mountings should be inspected for soundness. and the silencer and exhaust pipe for firm attachment. The use of wire for holding pipes and flanges in place is not unknown.
Check the degree of backlash between the bevel pinion and crown wheel by grasping the propeller shaft and endeavouring to move it backwards and forwards. If it is possible to rock the shaft to any extent, it indicates that either the pinion-shaft bearings need renewing, or that the meshing of the pinion and crown wheel are faulty through maladjustment.
Note should also be taken of excessive oil leaks, particularly from the bevel-pinion-shaft housing. Sometimes new oil-retaining washers will effect a cure.
If the vehicle has hydraulic braking, all brake-fluid pipes and unions should be examined for leaks. The same remarks apply to the fuel-feed system.
The general condition of the body is readily assessed, but there are one or two points deserving particular attention. Do not forget to raise and lower the tailboard to ensure that it works correctly. Faulty hinges cannot always be detected without putting them into action. The same, of course, applies to the doors.
The purchaser of a used vehicle would be well advised to drain the oil from the engine, gearbox and back axle and replenish with the correct respective grades before putting it into service. At the same time, all filters should be inspected and cleaned and, if a by-pass type of filter is fitted, the element should be renewed.