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Brake Fault Symptoms

BRAKE SYSTEM LAYOUT

These are typical symptoms a driver could experience with faulty or worn brakes. Check the list to know what to watch out for. Note: some of these symptoms may also be caused by your suspension system, but let Auto-Mech Cheddar Ltd check both for you.


VIBRATION ON THE STEERING WHEEL

What is it?

The steering wheel shakes while braking. The steering wheel shakes all the time while the car is in motion.

Why Does it happen?

Vibrations can be caused by brake judder – the brakes shudder when the pad meets the disc.

+ Discs could have different thickness around the diameter.

+ Discs could be warped due to overheating.

How will a Technician fix it?

For disc thickness variation, the thickness should be checked all round the diameter. Where the disc has varying thicknesses, both discs on the axle should be replaced. Note: it is not safe to only replace discs – brake pads must be changed at the same time to ensure peak braking performance.


NOISE FROM THE BRAKES

What is it?

This is usually a high pitched squeal, or can be a grinding noise.

Why does it happen?

+ Your brakes could be worn to the minimum where the back-plate is grinding on the disc, or the screech wear indicator.

+ The shim (which covers the back-plate of the brake pad) could be missing or damaged.

+ The caliper is sticking.

How will a Technician fix it?

+ Replace brake pads (and discs if damaged).

+Service/replace the caliper.


PULLING TO THE SIDE UPON BRAKING

What is it?

As you press the brakes, you feel the car pulling to the left or right. Note: this is different to poor wheel alignment where the car always pulls to one side while in motion.

Why does it happen?

+ The brake pads have been contaminated by oil or grease with inefficient braking on one side.

+ The caliper could be sticking – the brake pads on one side are unable to brake effectively.

How will a Technician fix it?

+ Check the brake pads and replace if necessary (always replace both sides).

+ Check the caliper for efficient braking and service/replace if required.


LONG/ SPONGY PEDAL STROKE

What is it?

This is the sensation where either you have to press the pedal quite far down to achieve deceleration, OR the pedal feels literally spongy or softer than usual when you depress it.

Why does it happen?

+ If your car has a brake drum system, the brake shoes are poorly adjusted.

+ Brake fluid – either there is air in the system, the fluid is leaking, or in poor condition.

+ Load sensing in or load proportioning valve has seized.

+ Brake hose are leaking or ballooning.

How will a Technician fix it?

+ Re-adjust the brake shoes.

+ Check the quality of the brake fluid, bleed that system and replace with new brake fluid.

+ Check the master cylinder and wheel cylinders for leakage and replace if required.

+ Check the brake hoses for any leaks or ”Ballooning” and replace if any faults are found.


HARD PEDAL

What is it?

When you depress the brake pedal you feel very little ‘give’ in the pedal. It is literally hard to press.

Why Does it happen?

+ Brake pads are ”glazed” because the friction material cannot cope with braking demands.

+ Caliper is sticking, holding the pads to the brake disc.

+ The brake servo unit is leaking, or has poor vacuum supply leading to low force applied to the brake system.

How will a Technician fix it?

Check the pads for glazing and replace them.

+ Service/replace the caliper.

+ Check the servo and replace or repair as necessary.


BRAKE ROUGHNESS

What is it?

As you apply the brake for the first time (usually after the car was parked for a while), there is a slight grinding.

Why does it happen?

The brake disc has become corroded usually in winter with the salted roads, or near the sea. The metal in the pad has rusted, and adhered to the disc (the rough wire) brush type sound happens as the corrosion is cleared off the disc.

How will a Technician fix it?

The corrosion usually clears from the disc after a few light brake applications. If corrosion is severe, the brake pads and discs should be replaced.


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