Suspension
Maintenance for Steering & Suspension SystemsThe vehicle’s steering and suspension system comprises of many components and assemblies, including steering racks, steering boxes, coil springs, leaf springs, shock absorbers, ball joints, bushes and mountings, stabiliser links, to name but a few. This feature focuses on the steering and suspension components such as the ball joints and track control arms. Due to the diversity of the UK vehicle parc, and the number of different component types required to service this parc, First Line calculate that approaching 5000 part numbers are required to offer a serious product range to the professional mechanic. This is why major supplier’s steering & suspension product ranges continue to grow. Recent MOT statistics reveal that 13% of cars fail on steering faults, and 13.25% on suspension faults alone. That’s many thousands of car owners that had serious steering and suspension faults develop on their car within the 12 months of their last MOT and were not found until their cars were inspected by the garage. Safety first. Steering and suspension assemblies and components are an important and integral part of the modern motor vehicle and are just as subject to wear, tear and damage as other parts. These parts are most certainly safety critical and also contribute to the effective and economical running of the vehicle. Use every opportunity to check the steering and suspension parts, not just at MOT time, but also during routine servicing and body/crash repair. A good marketing move would be to offer the customer/driver a free safety check. Check for wear in the joints and component. Some vehicle ball joints need to be checked ‘under load’, others ‘not under load’. Refer to the vehicle manufacturer’s handbook for the correct way. Check for worn or split rubber components, such as bushes, gaiters, boots and covers. The slightest ingress of dirt or water leads to ball corrosion and seat wear therefore leading to premature failure. Carefully check the new generation of aluminium suspension arms such as those fitted to Audi A4, A6 and VW Passat (this is not a complete list) as these could be prone to damage from kerb shocks, road damage and accidents. Front Lower Suspension Arm (Wishbone) There are a variety of designs similar to the illustration. This particular one is fitted to Volkswagen Golf. Although the illustration shows that the ball joint has been secured to the arm with bolts, there are some instances where the ball joint can be secured to the arm by rivets. Where the ball joint is secured to the arm with rivets, it is possible to remove the rivets by carefully grinding off the heads and driving out or drilling out the rivets ensuring the drill is centralised and the securing holes are not elongated. Secure the new ball joint using new fixings supplied with the ball joint. Bush replacement where necessary, should be carried out using a press and suitable mandrels and spacers. Ensure the bush is pressed in and centralised to the correct depth. Where the bush is a void type, it is important that it is positioned correctly so that the voids are located as per the original. Premature failure will result if this is not carried out correctly. A thorough examination of the suspension arm should be carried out before any remedial work is undertaken such as, the replacement of bushes or ball joints. Particular attention should be made for any signs of corrosion, accident damage or damage from the incorrect use of jacks and check for elongation or cracking around any securing bolt holes. If any faults are detected, the complete arm must be replaced. There is no margin for error with safety critical parts! Replacing the assembly When tightening inner-mounting securing bolts and the ball joint retaining bolts it is important, that this is carried out when the suspension is in the “loaded” normal ride height position and the arm is fully connected to the vehicle. If the mounting bolts are tightened when the arm is in the lowered position, the car is jacked up and no weight is on the suspension or wheel. As soon as the vehicle is lowered down on to its wheel, the bushes will be subjected to additional loads causing premature failure. The vehicle driver will at least be disappointed and inconvenienced when the failure takes place. The manufacturer will reject any pending warranty claim by the fitter as clearly, the assembly was incorrectly fitted. Once again, emphasis must be placed upon checking and resetting the wheel alignment when any work has been carried out on the vehicle prior to its release to the customer. All work and all securing bolts tightening should be carried out in accordance with the vehicle manufacturers recommendations and specifications.
SUSPENSION SYSTEMS
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