With the average age of vehicles on the rise in the UK, the market for suspension systems has seen a sizeable growth. Shock absorbers are extremely crucial to the safety of a vehicle. As the car grows old and has travelled through many thousands of miles, the shock absorbers deteriorate and wear out. Research studies show that the average car is likely to need at least one set of replacements during its lifetime, irrespective of vehicle type, driving style and usage.
The aim in shock absorber replacement should be to restore the vehicle to its original operating characteristics and give consideration to other suspension components that should be replaced simultaneously. This is where Boge has been able to carve a niche for itself in the automotive aftermarket.
Better than the Rest
Boge offers an extensive portfolio of suspension systems that assures both safety and comfort. The OE quality of Boge shock absorbers enables simple replacement with precision parts and assures the end-user of the quality, comfort and durability of the original factory specification. The full range of Boge shock absorbers, top mounts and service kits amounts to more than 3,600 part references across 43 different car manufacturers.
It is interesting to note that the sale of Boge shock absorbers continues to rise, irrespective of market conditions.
The basic principle behind the working of a shock absorber is that the valve system offers a progressive and controlled damping action. The valve components in Boge shock absorbers produce low relaxation that provides highly consistent damping force and characteristic precision, without adjustment. The mounting joints consisting of bushings and age-resistant, wear-resistant rubber materials form a highly durable and sound-proof link between wheel suspension and chassis.
A major challenge in the automotive industry is achieving greater fuel efficiency; Boge shock absorbers from ZF contribute towards these targets by manufacturing shock absorbers for passenger cars with lightweight materials on some vehicle applications, such as aluminium housings, which help in reducing the overall weight of the vehicle.
Boge shock absorbers are tested alongside other steering and suspension components in the vehicle during the development stage, enabling better fit and performance. The quality of suspension can have an adverse effect on other systems in the vehicle, such as ABS, Electronic steering, ESP etc. Choosing a sub-standard, low-priced option could compromise these potential safety critical systems. Boge’s OE quality and precision manufactured shock absorbers give the reassurance that none of these critical systems will be compromised and ensure the safety of the end-user as well as confidence for garages and motor factors.
The replacement new part, once fitted, is expected to provide the best possible performance for the customer, offering the safety and comfort felt in a new vehicle. If the internal damping rates, such as compression and rebound are not perfectly matched to the car manufacturer’s original specifications, it can affect other safety aspects such as emergency braking procedures. In such cases, the braking distances could drastically increase by up to 50% while driving at 40mph or more.
Common faults and diagnostics
The factors affecting a shock absorber and causing its deterioration are:
Road unevenness like potholes and ground waves that can pierce the shock absorbers.
Damage of the piston by salt residue, stones and water.
General wear and tear.
Old or worn/ damaged repair kits (bump stops) or missing protective gaiters.
These can lead to common faults in the shock absorber and mounting, such as:
Oil leaks: With each stroke, the piston rod transfers a small amount of oil to keep it lubricated. While a ‘misting’ of oil on the outer tube is normal, larger volumes indicate a failing piston rod seal.
Worn mountings: The top mount is the upper fixing between the shock absorber and the vehicle body. This is a compliant rubber-to-metal component that prevents damping and suspension forces and their associated noise and vibration from being transferred to the cabin. Normal wear, fitting errors or consequential damage due to the operating environment can deteriorate the rubber mountings, making noise and vibration more prevalent.
Side loading predominantly causes oil leaks on the shock absorber. Depending on the severity of the side loading, this may cause an accelerated rate of wear to the top mount and/ or its bearing but the majority of the time; it's the shock absorber that will have the issue due to the top seal wearing.
Always replace in pairs
A common sense evaluation of the risk involved in not replacing the safety-critical shock absorbers in axle pairs shows that the advice is not a mere marketing gimmick. The gradual deterioration in a shock absorber’s performance may go unnoticed by a driver, but a potential difference of 25% damping force between a worn and new damper will certainly make itself felt under heavy braking or other avoidance manoeuvres, with potentially disastrous consequences.
Top Mounts and Service Kits
Just like shock absorbers, top mounts too eventually wear out. It is therefore recommended that these are regularly inspected for wear, and certainly renewed whenever the shock absorbers are replaced.
Boge also offer a shock absorber service kit, to complement many applications in range that need them. The service kit comprises of a spring assister or bump stop and a gaiter that protects the shock absorber piston rod from road debris. In the case of gaiter replacement, there is the psychological aspect to consider, as replacing the more visible gaiter can help reassure the customer that a thorough job has been done.
Wayne McCluskey, ZF Services advises, “Spring assistors should be changed if they are worn or degraded, or if they are contaminated with oil from a previously failed shock absorber. The oil attracts grit and this can damage the chromed finish on the piston rod. Under no circumstances should spring assistor lengths be shortened in order to aid shock absorber fitment as this could damage the shock absorber valve under full compression”.
2 years/ unlimited mileage warranty.
Optimised for safety with the ability to respond to any driving condition.
Wide application coverage and range availability, assured with OE quality.
The right shock absorber for every application, ensuring an ‘as good as new’ feel after replacement.
High corrosion resistance, low mechanical seal wear and top handling comfort through low friction.
State-of-the-art manufacturing and materials for precise and even stroke arrest.
The high-performance oil ensures a constant damping force in all temperature ranges.