Neglecting a vehicle’s braking system can lead to expensive repair costs and vehicle downtime, not to mention increased risk to the driver should it underperform. Especially at this time of year where road surfaces become more slippery and weather conditions affect stopping distances.

So are your fleet's brakes in the best health? A number of factors can influence their lifespan, from the weight of a vehicle to the types of roads it is being driven on, which means it has never been more important to keep a close watch on their condition.

Impact of electronic driver aids

Manufacturers are fitting smaller/thinner brake components as part of a weight-saving strategy to improve efficiency; a trend that Peter Lambert, Kwik-Fit fleet director, suggests could result in brake parts on modern vehicles needing to be replaced more frequently than parts on older, heavier vehicles.

‘Vehicles with electronic driver aids (lane assist, ESP etc) are also becoming more commonplace,’ Lambert continues. ‘These vehicles can use brakes without the knowledge or intervention of the driver, which can potentially increase brake wear, especially on the rear.’

And how does the cost of brake repair on modern cars with bigger wheels and more powerful engines, compare to older, less advanced models?

‘Braking systems overall are becoming more complex with additional electronics being added, which is affecting the cost of other components like calipers with built in-motors for electronic parking brake (EPB) systems, or wheel bearings with integrated wheel speed sensors,’ Lambert explains.

‘Some EPB systems are already becoming an expensive repair for drivers as components fail relatively early in the life of the vehicle. However, prices for the majority of common service components (pads/discs) have been relatively stable for a number of years. The cost of these is largely driven by competition versus the OEMs, with more popular vehicles having a tendency to have lower cost parts.’

Regenerative braking

Most common on hybrid and electric vehicles, regenerative braking systems function very differently to conventional brakes. Instead of using the friction between a pad and disc, they use the resistance of the magnets within the traction motor to slow the wheels.

As well as generating electricity which can be used to drive the car, regenerative braking means drivers don't use the friction brakes when slowing gently. This means hybrid and electric vehicles tend to offer longer service life on brake pads and discs than a conventional car.

However, regenerative braking is ineffective when the battery is fully charged, and a friction-based system is still required to slow the car under difficult conditions such as wet roads or emergency stops. It is just as important that these work first time when the driver requires more stopping power, and they should be inspected as frequently as the brakes on a petrol or diesel model.

Driving style

The AA stresses that brake wear is an indeterminate science – in some cases the brake pads will do 70,000 miles while other drivers will find they need changing after only 25,000 miles. The type of vehicle, type of use and driving style all have an influence on component lifespans.

Although town driving involves frequent application of the brakes, such low speed use doesn't cause as much wear as heavy braking from high speed. Motorway slip roads are one of the main culprits and this is more likely to contribute to disc warping, causing juddering of the vehicle.

Drivers are also advised to try to avoid holding the car back with the brakes on long downhill runs, as this will put a lot of heat into the discs, leading to increased wear and potentially warping or brake fade. Using a lower gear so engine braking can be exploited to reduce pressure on the brakes is recommended.

As well as the risk of warping, heavy braking causes brake fluid to heat up. Brake fluid is hygroscopic, which means it absorbs water from the atmosphere over time, and in extreme cases this can boil and vaporise, leading to a spongy pedal and a reduction in performance.

Keeping brakes healthy

Brake checks are an important part of fleet maintenance, and drivers should be encouraged to be alert for signs or brake disrepair. Drivers who regularly clock up high mileage should have their brakes checked at least every 12 months, regardless of service intervals.

Kwik-Fit’s Peter Lambert advises that these checks should include a full strip and inspection of the system, not just a “peer through the wheels” check.

ATS Euromaster also recommends fleet drivers take advantage of a free brake check to ensure their cars and vans have maximum stopping power. The complimentary check is suitable for all makes and model of car and van up to 3.5 tonnes.

Brake checks include a thorough inspection of the pads, discs and shoes, plus calipers, brake lines and cables – with any necessary remedial work highlighted to the driver. Technicians will also inspect the tyres – which also play a critical role in a vehicle’s ability to stop safely – and brake lights.

‘Fleets can’t afford vehicle downtime as the result of an accident, much less potential injury to a driver or other road users; a free brake check between scheduled services is a simple way of maximising safety and supporting Duty of Care. Having confidence in your brakes is also one less thing for drivers to worry about,’ comments Peter Fairlie, ATS Euromaster’s group sales director.

Maintenance

Ideally fleet operators will have a policy in place that covers brake maintenance. While some manufactures set service intervals as high as 30,000 miles, it may be worth considering lowering the interval so worn brake pads are captured as soon as possible.

‘Northgate has a policy of replacing brake pads during a service if they are more than 50% worn as the chances are they will not last to the next service interval,’ explains Gary Dean, UK technical support manager at Northgate Plc.

‘This may seem an additional cost but in fact it is much more cost effective than having to replace them as an emergency purchase in-between services and additionally it keeps our customers on the road longer with reduced downtime.’

A policy should also specify the quality of the brake friction material being fitted. Only OE quality parts should be used, and any service providers should be instructed to change any other brake consumable parts as recommended by the manufacturer.

Brake fluid must be changed at least every two years and low brake fluid should be immediately investigated, as this can be a sign that the brake friction material is worn close to a point where replacement is needed.

Signs of severe brake wear:

• Vibration in the steering wheel when stopping.

• Grinding or squealing noises.

• Increased braking distances.

• Longer pedal travel

• Feeling the car “pull” to the left or right when stopping.

• A weak emergency stop.

• A bad smell after coming to a hard stop.