Brakes: disc

The brake disc is attached to the wheel hub, which rotates with the wheel, it slows down the wheel to stop your vehicle. The front brakes do most of the work. When braking, the weight of the vehicle is concentrated on the front. This is why front brakes are generally fitted with discs.

The disc brake is a high-performance braking system for vehicles with wheels in contact with the ground. This system converts the vehicle's kinetic energy into heat, which must be dissipated as quickly as possible.

There are two types of brake discs:

• Solid discs
• Vented discs and drilled/vented discs, which can also be slotted.

A solid brake disc is very strong. They are usually found on older vehicles and they are cheaper.

The vented brake disc has an empty space between the two faces of the disc, for better ventilation and cooling.

The slotted and vented brake disc also has holes distributed over the entire surface of the brake track. These holes perform the same function as the grooves found on some models, allowing water to run off more easily.

This type of disc can sometimes also be grooved.

Often, when certain symptoms of brake wear are present, the solution is not always to replace the parts. Sometimes, simple maintenance will suffice.

The discs and pads are removed from the vehicle, cleaned and then put back on. This simple operation significantly increases the life of your brakes and is much cheaper than replacing them.

Brake servicing is recommended at least once a year, but you may need to do it more frequently depending on how you use your vehicle.

Brake discs are parts that wear relatively quickly with use. It's important to inspect them regularly and replace them if necessary.

Brake discs should be replaced when their minimum permitted thickness [expressed in millimetres] has reached the limit prescribed by the manufacturer.

For a longer service life, it's advisable to replace brake pads regularly to avoid excessive wear. This will increase the life of your brakes and also their efficiency.

Grand Cherokee V6 3.0 CRD front brake discs and pads replacement

Disc thickness can be checked using a calliper.

The measurement is taken at 4 positions offset by 90°. The thickness is the average of the 4 measurements. It must not be less than the dimension prescribed by the manufacturer.

To check the warpage of the disc, a dial gauge with its support must be mounted on a fixed part.

The disc warpage is measured 10 mm from the edge of the disc. The disc is then rotated by hand and the dial gauge is reset to the minimum value. After a complete rotation, the warpage should remain within the vehicle's original tolerance.

Brake disc cracks due to heat :

The braking surface of the brake disc shows cracks that run continuously from the edge to the centre of the disc.

Front brakes :

Rear brakes :

Brake disc

Preformance brakes