If the car has passed all of the tests so far, then a road test will enable you to discover many of the potential drive/suspension faults without getting your hands dirty.
The author and publishers can assume no responsibility for the consequences of any of the following advice. It is up to the individual to ensure that the car is driven in a safe manner with full regard to the safety of other road users.
If you are to drive the car then ensure that you will be not inadvertently break any motoring laws in the process. This means that the car must be roadworthy and taxed and that you must be properly insured. If the vendor is to drive, ensure that he or she is acting within the law, because you could be regarded as an accomplice if the vendor is stopped and charged of an offence by the police during the test drive.
For the sake of safety, begin at moderate road speeds and do not try anything fancy until you are satisfied that the road holding, handling and brakes hold no nasty surprises. If you are not familiar with the on-road behaviour of the Beetle then it is recommended that, if possible, you arrange for an experienced Beetle driver to carry out part or all of the test drive. The experienced Beetle driver will be able to detect problems with the engine, unusual noises from the drive train, deficiencies in the handling and braking which may not be apparent to the inexperienced.
If the car shows signs of 'floating' at speed then the dampers are worn; if the front of the car nose-dives as the brakes are applied, if the bonnet pitches up and down as the car moves away from a standstill, expect to find worn or leaking dampers. Any car with worn dampers is unsafe to drive at speed, so continue the test, if at all, at slow speeds.
On an empty stretch of road, brake to a standstill from about 30 mph and note whether the car pulls to one side (worn or contaminated brakes). If the brakes have to be 'pumped' before they will operate properly then there is air in the system. A clonk on braking could indicate suspension problems or a loose brake calliper (disc braked models only). If a clonk can only be heard when the car is first braked when travelling either forwards or in reverse, the calliper pistons, could be sticking. Repeat this test using the handbrake.
In all gears, accelerate and decelerate sharply to see whether the car can be encouraged (under provocation) to jump out of gear! If the car jumps out of first gear on the overrun then the chances are that the fault is due to incomplete gear engagement caused, in turn, by a wrongly positioned gear shift lever plate. Reverse the car a short distance and again brake to a halt, listening for clonks which could indicate suspension problems or a loose brake calliper.
If at any stage in these tests any doubts emerge regarding the brakes or suspension, then it is best to discontinue the road test on the grounds of safety.
Increase speed to normal road speeds and repeat the braking and gearchange tests, when any deficiencies in the engine, transmission or suspension not previously noted will be accentuated.Stop somewhere off the public highway. Engage the handbrake, then slowly let the clutch out, depressing it again immediately the engine begins to labour. If the car begins to creep forwards then the handbrake is out of adjustment or the rear brakes are worn or contaminated. If the engine does not labour appreciably then the clutch is slipping and in need of attention.
Slow down to 25-30 mph in fourth gear and press the accelerator pedal fully down. If the engine misses or shows hesitancy then this could indicate a weak mixture, as could pinking – otherwise known as pre-ignition. Pinking has a host of other possible causes including wrongly set ignition timing, an overheated engine, air induction or pre-ignition caused by very hot carbon or tiny metal burrs on the cylinder head which ignite the mixture ahead of the appropriate time. The sound of pinking is that of the pistons tipping in the bores. In time, pinking wrecks an engine. If the engine knocks, then it is almost certainly due for new big-end bearings and a crankshaft re-grind – in effect, a 'bottom end' rebuild or an exchange engine.
When exiting a corner check that the steering wheel returns to the straight ahead position; if not, then suspect partial seizure in the kingpins.