Brake inspection

Brake Inspection

When checked all four wheels for brake inspection, it was disc brake with callipers, the front were non vented the back was vented disc type.
The Brake pads had enough treat left on it but the rear brakes were worn unevenly and the inside of the disc had a few chips in it.
Carrier plates need replacing or servicing

30mins to 1 hour is enough to do a full brake service, maybe 90mins if you are new to it.

3 Different drum brakes

Servo:  Its not connected at the bottom. The brake servo unit intensifies the force of the driver’s foot on the brake pedal. If the driver starts braking, the connecting rod moves left, pressing the seal of the double valve against the valve seat, thereby closing the connection between the two chambers

Simplex:  the Simplex drum brake has the trailing shoe to the right and the leading shoe to the left. The shoe is called leading, if a certain point of the rotating drum passes the spreading mechanism (in this case the wheel cylinder) before passing the anchor-pin side. This creates a wedging effect, which produces a relatively large braking force in spite of only little pressure on the brake (self enhancement). With the trailing shoe the effect is the opposite.

Duplex: The Duplex brake has two leading shoes in the roll direction (i.e. on the left). Reversing however, causes these to wear.

Brake Pads, Disc and Piston

Brake pads should be replaced every now and then, the minimum your pad can be is 1mm, so have to keep a look out for that. You don't want it to completely ware off and damage your brake disc.

BRAKE DISC
The brake disc is the disc component of a disc brake against which the brake pads are applied. The weight and power of the vehicle determines the need for ventilated discs, The "ventilated" disc design helps to disperse the generated heat for faster cooling. Discs are usually damaged in one of four ways, scarring, cracking, warping or excessive rusting.

RUN OUT and THICKNESS OF DISC
The Run out is measured using a DTI gauge, once its installed right, spin the disc and measure the maximum and minimum run out, if its out of the manufactures range then it can be machined.

Thickness of disc can be measured by using a micro meter, you need to measure the inner thickness and the outer thickness, and if the difference is too much then it can be grinded down. 

SLIDES and THE PISTON

The movement of the pistons is controlled by a hydraulic system. When hydraulic pressure is applied by pressing the brake pedal, the piston is pushed forward to press the inner pad against the rotor while the housing is pushed in the opposite direction to press the outer pad against the rotor, hence generating a hydraulic clamp around the rotor. For the fixed (non-floating) caliper type of disc brake system, each piston presses the brake pad against its respective side of the brake rubbing surface, as shown in Figure 

THE BRAKING SYSTEM

GENERAL PRINCIPLE

1. Kinetic to heat energy

2. Force of brake pedal

3. Forces the push rod in the brake booster which in turn forces the primary piston in the master cylinder forward, the fluid pressure pushes the secondary piston

4. The brake pipes carry fluid pressure to proportioning valve then to the brake callipers

5. the piston forces the brake pad against the disc rotor  

6. The friction reduces the rotor speed.

7. The wheel being attached to the rotor is therefore slowed down.

Most modern cars have disc brakes on the front wheels, and some have disc brakes on all four wheels. This is the part of the brake system that does the actual work of stopping the car.the most common type of disc brake on modern cars is the single-piston floating calliper.

 

How disc brakes work!   VIDEO

How to Bleed brakes!

1. Clean out reservoir
2. Top up with new fluid
3. Select DOT
4. Open bleeder nipple
5. Put block under brake pedals
6. Pump 6 times, hold down
7. Open nipple and close again
8. Pump 6 times and hold down
9. Open nipple and close again

Why do we bleed?

To replace old fluid, or if you are replacing a brake park, if there is air in there you have to bleed it.

Drum Brakes

Brake shoes, with linings attached, are situated inside brake drums. These drums revolve with the wheel. When pressure is applied to the brake pedal, hydraulic fluid in the braking system forces the brake shoes outward until the linings come into contact with the inside of the drum and force it to stop.

Disc Brakes

These operate on a similar principle, except that the brake consists of a stationary caliper, with a disc revolving with the wheel. When the pedal is pressed down, hydraulic pressure forces pads in the caliper to clamp on the disc, much like the operation of a bicycle brake. Most late model cars have disc brakes or a combination of front disc and rear drum brakes.

Brakes are sensitive to heat, water and moisture, and the pads and linings wear every time you put your foot on the brake pedal.