Friday, March 5, 2010

MECHANICAL/ELECTRICAL INSPECTION


This frame head is in a very sad state, and illustrates just how badly even very thick section steel components can rust if maintenance is skimped. The rotten cover plate should set alarm bells ringing, even if you were to jail to notice the rot on the off-side base plate. If you find rot here, the best advice is to find another car.
Whether you undertake the mechanical examination or the test drive first is your own decision. In favour of test driving first is the fact that some mechanical faults might come to light so that you can rule out the car without getting your hands dirty! On a more serious note, the mechanical examination might reveal faults which would make a test drive risky if not dangerous and, for this reason, the author recommends that you check the car before taking it onto the road.
Begin your inspection inside the car where you can remain clean and (hopefully) dry. Check all of the electrical equipment; lights, wipers and horn. Grasp the steering wheel and try to lift and lower it; movement indicates poor mounting. Turn the steering wheel and try to ascertain how much the perimeter moves before the front wheels react. If the steering wheel turns by more than an inch or so then the problem could be cause by worn kingpins, a worn or maladjusted steering box/rack or a loose mounting. If you drive a car with a lot of null steering wheel movement, then the front wheels can react freely to bumps in the road and you have no way of knowing which way the car will jump when a front wheel hits a bump or pot-hole. Check that the windscreen is free of cracks and scratches (an MOT failure depending on country and current standards) and that all of the rubbers are in good condition (not perished and free from cracks).
Press the brake pedal and hold it down. If the pedal is spongy then there is air in the system, which will have to be bled and the cause of the air found and rectified. If the pedal sinks slowly to the toeboard then the master cylinder is faulty.
Remove the rear seat base and check the condition of the wiring and the battery. The wires' insulation must be intact and free from signs of scorching (indicating a short to earth fault which, if not cured, can result in the loom catching fire), and the battery should be clean, free
39from spillage and securely fastened. Check the level of the electrolyte in each cell, and use a torch to see whether the plates are buckled, in which case the battery is on the way out.
Check all seat belt mounting points by tugging as violently on the belts as you can, check the condition of the seat belts and mechanism because frayed or damaged belts are an MOT failure point.
Check that window winders, screen washers and all instruments work.
'Bounce' each corner of the car, that is, push it sharply downwards and let go so that the suspension pushes upwards. If the corner rises, falls and rises again then the damper is faulty. This is a very un-scientific test, and damper problems are more easily detectable on the road. If, however, bouncing the car indicates ineffectual dampers, don't drive the car on the road, because worn dampers reduce tyre grip to an unbelievable degree.
Then move to the engine bay. Firstly, if there is a strong smell of petrol and the fuel delivery system is leaking then immediately disconnect the battery and don't run the engine until the cause has been found and dealt with. Grasp the crankshaft pulley firmly and try to move it backwards and forwards; if the movement (crankshaft end float) is much greater than five 'thou (.13mm) then the engine requires attention. Try to lift the crankshaft pulley to test for worn mains; if the pulley can be pulled up and down then the crankcase will have to be align bored and the crankshaft probably reground, an expensive repair.
If you have a compression tester, use it! Remove all four spark plugs (marking the leads if you are unsure of which goes where), and get an assistant to turn the engine over on the starter motor while you check the compression for each cylinder in turn. This normally runs in the range of 100-142 pounds per square inch. If one or more cylinders are lower than the others, apply a little engine oil through the plug hole (to seal the piston rings) and re-check. If the pressure is now OK then the problem lies with the piston rings and cylinder bores; if the low pressure persists than the leakage is past a valve stem, and a cylinder head overhaul will be needed.
Check the engine oil level and the condition of the oil; if you don't know what signs to look for then take along someone who does! Check the condition of the spark plugs, leads, distributor cap (look for minute splits) and the points (check that the surfaces are level and not pitted). The general condition of the engine bay can tell you a lot about a car. If it is dirty and covered with oil, then maintenance has obviously been skimped on – the Beetle engine is good for well over 100,000 miles if cared for, but a neglected engine will have a much shorter life span.Check the condition of the wiring, looking for burns and abrasions and, if your bodywork inspection revealed that the rear chassis/damper bracket mounts have been replaced, lift the sound deadening material from the engine bay side and check that the wiring underneath is not burned. Check that the wiring is original and that it has not been added to or otherwise tampered with.
Check that the tinware is all properly fastened into place. This might not seem to be terribly important, but the author has witnessed a shattered dynamo pedestal which was broken by violent vibrations caused by unfastened tinware.
Whilst the rear of the car is raised for the bodywork/chassis inspection, check the rear brakes,suspension and wheel bearings. There are small inspection holes in the brake backplate through which, with the aid of illumination from a torch, you can see the thickness of the brake lining. If there appears to be less than 0.1 in. of frictional material left on the brake shoes then they will have to be renewed. Using a screwdriver (preferably with an angled blade) or the proper tool, check that the brake adjusters are not seized and that the brakes are correctly adjusted (see Chapter Four). Maladjustment indicates shoddy maintenance; sticking adjusters indicates a total absence of maintenance!
Check the brake backplates for signs of brake fluid or, perhaps more commonly, oil contamination. The former means obtaining and fitting wheel cylinder seal kits; the latter entails obtaining and fitting a hub oil seal kit.
Check the rear tyres for uneven wear. Excessive wear in the centre or at the outside edges of the tread indicates over or under inflation respectively. If the tyres are worn on one side only, ask whether they have previously been fitted at the front of the car (indicating ill-adjusted front
tracking). If not, then suspect that the spring plate has, at some time, been unbolted from the hub and replaced in a different position. which will cause toe in or out. In addition to increasing tyre wear, wrongly tracked rear tyres will suffer reduced grip, so this is a problem that
needs sorting before the car is used on the road.
Check the condition of the handbrake cables and, if they are frayed or if they stick, make a note to that effect. Check the brake pipes for corrosion, kinks or damage, and the flexible hoses for any signs of damage or perishing. Check the condition of the drive shaft gaiters/boots. Splits are an MOT failure point — leaking gaiters on swing axle cars must be remedied before transaxle oil is lost.
Check the transaxle and the underside of the engine for obvious oil leaks, which must be traced and remedied. If the entire underside of these units is covered with oil and you are seriously interested in buying the car, wipe off as much of the oil as you can and re-check to establish the cause of the leakage following the test drive. An oil leak from the clutch housing could emanate from either the gearbox input shaft seal or the rear engine oil seal — the latter is more common but both require the removal of the engine and the latter the removal of the clutch as well.
Check the condition and correct adjustment of the clutch cable, and check that the clutch return spring is not broken.
Check all visible wiring — most especially the starter solenoid feed wire — for insulation damage. Check the bump stops and all visible bushes for perishing. Check the heater ducting for damage and the exhaust/heat exchangers for leakage and general condition. Exhausts are not too expensive but are an MOT failure point; good quality heat exchangers cost rather a lot.
Most importantly, use a torch to illuminate the visible section of the fuel line; if you have the slightest suspicion that it may be corroded then you must budget for immediate replacement. This is neither an inexpensive nor a pleasant task.
Whilst the front of the car is raised for bodywork/chassis inspection, take the opportunity to check the front brakes, wheel bearings, suspension and steering gear. Check drum brake backplates for fluid leakage, use a torch to check the shoe material thickness through the hole provided. Check the condition of the lines and flexible hoses, and check for fluid leakage at unions. Again using a torch, check the visible portion of the fuel line (see previous comments). Check the dampers for leakage and visually check for perishing of all rubber components.
Check the tyres for uneven wear. Wear concentrated on both sides of the tread pattern or in the middle of the tread pattern can indicate simple under or over inflation respectively; wear on one side of the pattern could indicate either that the tracking is wrongly set (an easy adjustment which should be carried out professionally) or that more serious problems lie elsewhere in the suspension.
On cars with torsion arm front suspension, check that the beam is not damaged, because it is possible for the suspension to be thrown out by frontal collisions. Check that the notches in the large hexagonal eccentric bushes located in the top of the stub axle assembles are both facing forwards; these set the front wheel camber, and if they are inserted wrongly then the handling will be adversely affected and tyre wear will be high.
Place a lever under each tyre and try to lift it — taking care not to unbalance the car from the axle stands supporting it! Vertical free movement indicates kingpin problems. Grasp each tyre at the nine o'clock and three o'clock positions, and try to rock it; movement indicates worn wheel bearings. Turn the wheels from lock to lock, feeling for roughness in the steering box (expensive) and either stiff or loose points probably caused by the steering damper (easy repair).

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