Bringing a classic car back to a condition where it will be classed as roadworthy by the relevant authorities is a responsibility that cannot be taken lightly. Attending to the underbody of the vehicle- in particular its brakes, suspension and steering should always be a major priority.

If the vehicle under scrutiny pre-purchase is in running order, then the buyer will be able to get a clearer picture of the underbody's state of health.

The first stage in any road test is to try the brakes. The car should stop smoothly with no fading (diminishing of stopping power), and it should track in a straight line.

A grinding or scraping noise indicates that the brakes may be worn down past the linings and will need to be replaced.

If the car pulls to one side when braking, or the brake pedal goes down slowly, the hydraulic system may be leaking.

An almost certian way to test if brake fluid is leeking to check the examine of each wheel , as well as around the master cylinder.

Next step in a pre-purchase check is to test the steering, preferably under a few different conditions. If the steering wheel starts to shudder or wander at certain speeds, means that the front end may need a rebuild.

If there is a lot of play in the steering wheel before the car starts to tum, the steering linkage may be worn, or the steering box may need an overhaul.

If the vehicle has been standing for many years, the restorer can assume that a major overhaul to all the underbody systems is on the cards, a factor that must be taken into account in the seller's asking price.

It is a fact that while most amateur mechanics will know their way around an engine, a lot fewer will possess the necessary knowledge and experience to work on a vehicle's underbody- a task that carries a lot of responsibility in ensuring driver and passenger safety as well as their comfort.

 

Most UK and European classic cars of the Fifties and the early Sixties came fitted with drum brakes in the front, which were by then regarded as being cumbersome and outdated.

Unless the restorer is a stickler for authenticity, they should put safety first and follow the trend to replace the drums with discs. Disc brakes are so much better in many ways and will not cost a fortune to replace.

If the plan is to fit a more powerful engine budget then the restorer should consider installing power-assisted brakes.

Playing no less an important role in a classic car is its suspension.

The main purpose of a car's suspension is simply to keep all four wheels on the road. Even if the vehicle will be riding on the finest of tyres after the restoration, they will provide precious little in the way of road-holding if the suspension is not spot on.

If the model being restored is from the Sixties and sold in large quantities in its day, original replacements may still be available, although liable to be expensive.

A more obscure model and especially one that goes back to the Fifties will be impossible to trace, and the only likely alternative will be aftermarket parts.

Costs of these parts are usually low, while quality is fairly high.

The same procedures apply to the vehicle's shock absorbers. Going back to the pre-war years, hydraulic type shock absorbers were popular and remained so until the Sixties. It was then that they were replaced by telescopic shock absorbers which are popular today.

When a vehicle's wheel goes over a bump in the road, the suspension spring allows for an according adjustment allowing the vehicle floor to remain level.

The suspension spring provides essential movement for the wheels while the shock absorber act as a form of vibration damper for the spring.

Hardly any system connects the driver so directly to his or her car than its steering. A variety of mechanical solutions exist to make the car change direction as the driver wishes.

Nearly all common types of steering follow the so-called 'Ackermann' principle, developed by the renowned German of hat same name more than two hundred years ago. The revolutionary principle behind the Ackermann theory is that the axle itself does not turn, the front wheels instead.

Most European and UK cars of the Fifties and Sixties were fitted with rack and pinion steering.

Since then, this design has consistently proved to be not only effective, but compact and inexpensive to produce and maintain.

In smaller family saloons and sports tourers, there is no real reason to change anything, only to ensure that the system is in the best of working condition.

Most larger saloons of the Fifties and Sixties were notorious for their cumbersome steering. Restorers who want to improve their driving experience often consider fitting power steering, which will dramatically improve their driving experience, especially if the car is to be driven in the city.

Once again, the fundamental decisions on how to bring the car's suspension up to the levels required to make it roadworthy and pleasant to driven can only be taken in the workshop during the initial pre-renovation inspection.

Unless the owner is a real experts on suspension, the chances are that any work required will need to be farmed out to experts.

The same may well apply to springs, one of those components to which little attention is normally paid although they to carry out a very important task in the role of the vehicle underbody.

Simple though they may appear, springs pay a considerable influence on a car's handling characteristics. With no springs to support the car’s suspension, the hard jolts which are felt when driving over potholes or bumps in the road would be transmitted directly to the chassis frame or body, placing an undesirable load on them.

The stiffness of the springs, the so-called spring rate, is defined as the relationship between the spring travel and the load imposed on them. The spring rate depends on the material used to produce the springs (we'll limit ourselves to steel springs in this instance), on its specific qualities such as the quality of the steel and size and shape of the springs.

These specific qualities will allow the springs to absorb the forces exerted on them as they become compressed.

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Changing brake pads

Restoring rear axles

Shock absorbers