Shocks: Top advice from Monroe

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Oil, tyre tread and pressure, brakes… Many drivers might be familiar with checking common parts on their vehicles but how many drivers check their shocks? Read our guide to shock absorbers and you could win awesome prizes in our competition!
The 2013 holiday season is approaching and even though road crashes are not restricted to these concentrated times of travel, there will be far more cars on the road.

To make sure you reach your destination safely, it is advisable to check your vehicle for faults. Besides checking oil level, tyre profile depth and pressure and brakes, you should also check your shock absorbers as they could pose a safety risk.

Why should you check your shocks?

Shock-absorbers are important because they form an integral part of a vehicle’s safety triangle:  steering, stopping and stability. Neglecting any one of these can result in an unsafe vehicle. Shock-absorbers are mostly associated with dampening the car’s movements for ride comfort. They also contribute to keeping tyres in contact with the road.

Over time they can wear out and their ability to contribute to keeping the car’s tyres on the road can be reduced. As this is a gradual wearing process, road users are usually unaware of the diminished capability of this vitally important component.

The role of shock-absorbers is to:

•    Prevent excess spring movement
•    Control body roll and pitch, stabilising the body of the vehicle
•    Maintain tyre contact with the ground
•    Improve road-holding and braking
•    Ensure a comfortable ride

Monroe shock-absorbers Southern Africa marketing manager Philip Lutz, said: “The life of a shock depends to a large extent on how and where it is driven. If it is driven fast over a bumpy road the shocks will wear out sooner than those driven on a smooth road..

“As a rule-of-thumb, shocks last about 70 000km before showing signs of wear. You should check your vehicle’s shocks every 20 000km, particularly after the 70 000km mark. For optimum safety and control, Monroe recommends replacing shocks at 80 000km.”

Worn out shock-absorbers can have a negative effect on a vehicle’s safety and driver control when compared with new ones:

1 Increased braking distance:
According to tests carried out by TUV Rheinland, at 80km/h on a straight road with only one driver in the car, braking distance increases by 2.6m when shock-absorbers are worn. The braking distance of a fully loaded car at 70km/h (with a driver and three passengers) reaches 11.3 meters (Automotive Safety Centre, Milan).
2 Aquaplaning:
Vehicle aquaplaning can occur at 109km/h in wet weather if a vehicle has worn shocks.
3 Increased tyre wear:
After 9000km a car with 65% worn-out shocks causes a 10% increase in tyre wear, compared to the same car equipped with efficient shock-absorbers. Premature tyre wear translates into increased replacement and running costs but above all a major reduction in safety, according to research study by Monroe at the Centro Tecnico Pirelli.
4 Failure of ABS/ESP:
Worn shock-absorbers influence the functioning of the anti-lock braking system and the electronic stability program.
5 Decreased grip:
During cornering or hard braking, tyres will be unable to provide sufficient grip resulting in a loss of control.

Check your shocks with these six simple steps:

First ensure you vehicle has been driven recently and is on a level surface.
1 Press down firmly on one corner of the vehicle.  Your vehicle will push down and bounce back up again.
2 As it bounces up it should rise above its starting point and then settle in one bounce.
3 If it drops below its starting point and rises back up to it, your vehicle’s shock more than likely will need replacing.
4 Conduct this test for each shock absorber (each corner of your vehicle).

Aside from using a suspension tester or the “bounce” test, here are some things to look out for:
1 Patchy tyre wear
2 Oil leaking from the shock.
3 Worn rubber bushings
4 Dented or bent shocks
5 Marks on the shock piston rod
Lutz said: “It is not standard to have your shock absorbers checked at a routine service, so you need to make sure this is done by the fitment centre. Shocks which are efficient, can save your life.”

Tenneco, manufacturers of Monroe shock absorbers, is one of the world’s largest designers, manufacturers and marketers of emission control and ride control products and systems for the automotive original equipment market and the aftermarket. Contact: 011 574 5603 or click here for more information.