Hydraulic Brake System Fundamentals Parts Technician First Period Material Identification and Calculations 270103k.

Hydraulic Brake System Fundamentals

Parts Technician

First Period

Material Identification and Calculations

270103k

© 2013, Her Majesty the Queen in right of the Province of Alberta

Figure 1 - Maximum stopping distances allowed under the conditions indicated.


Figure 2 - Braking levels.


Figure 3 - Energy conversion during braking.


Figure 4 - Stopping power.(Courtesy Allied Signal)


Figure 5 - Effect of weight on stopping power requirements. (Courtesy Allied Signal)


Figure 6 - Effect of speed on stopping power requirements.(Courtesy Allied Signal)


Figure 7 - Effect of speed and weight on stopping power requirements. (Courtesy Allied Signal)


Figure 8 - Conduction and radiation.


Figure 9 - Natural convection.


Figure 10 - Forced convection.


CAUTION

Adequate airflow to the brakes for cooling is vital to their safe operation. Never make modifications to the vehicle that would reduce the amount of airflow to the brakes.


Figure 11 - Air scoop.


Figure 12 - Forms of heat transfer.


Figure 13 - Braking system.


Figure 14 - Pascal’s Law.


Figure 15 - Pascal’s Law helpful hints (Tradesperson’s Triangle).


Figure 16 - Hydraulics used to multiply force.


Figure 17 - Increased system pressure and output force due to decrease in the input piston size.


Figure 18 - The total output force from the five small pistons is the same as the force from the single large piston.


Figure 19 - Hydraulic lines and flexible hoses.


Figure 20 - Hydraulic brake system.


Table 1 - Composition and wet and dry boiling points of brake fluids.

Rating Composition Colour Minimum Wet Boiling

Point Minimum Dry Boiling

Point

DOT 3 glycol-based amber 140°C (284°F) 205°C (401°F)

DOT 4 glycol-based amber 155°C (311°F) 230°C (446°F)

DOT 5 silicone-based purple 180°C (356°F) 260°C (500°F)


Figure 21 - Brake fluid.


Figure 22 - Moisture contamination graphs for DOT 4 brake fluid.


CAUTION

DOT 5 fluid should never be used in ABS systems. Since DOT 5 fluids do not absorb the water that finds its way into the system, the water can collect in the valves of the ABS system, corroding them and rendering them inoperative.


DANGER

Brake fluid can cause skin irritation, particularly in open wounds and sores. Protective clothing and eyewear should be worn when servicing hydraulic components.


Figure 23 - Complete brake system components.


Figure 24 - Pressure differential valve.


Figure 25 - A metering valve.


Figure 26 - The location of the proportioning valve.


Figure 27 - A combination valve showing the three separate sections making up the one valve block.


Figure 28 - Tandem reservoir master cylinder.(Reproduced with permission of Ford Motor Co.)


Figure 29 - Master cylinder body and reservoirs cast as one piece (left) and a master cylinder with a removable plastic body (right).


Figure 30 - Exploded view of a master cylinder.(Courtesy General Motors of Canada Limited)


Figure 31 - Mechanical linkage of a master cylinder mounted on the bulkhead/firewall.(Courtesy Motor Information Systems)


Figure 32 - Front/rear split brake system typical of RWD and 4WD vehicles.


Figure 33 - A diagonally split brake system.


Figure 34 - Different size brake reservoirs. (Courtesy Motor Information Systems)


Figure 35 - Master cylinder brake fluid switch.(Courtesy General Motors of Canada Limited)


CAUTION

Copper tubing must never be used in brake hydraulic circuits because it will become work hardened from vibration much more readily than steel and cannot withstand the high pressures in the brake system.


Figure 36 - A double-lap flare (SAE) and an ISO flare.


Figure 37 - Fluid in the hydraulic system at rest.


Figure 38 - Brake system (light application).


Figure 39 - Brake system operation (medium application).


Figure 40 - Brake system operation (heavy application).


Table 2 - Common replacement components and related sales.

Failed Component Related Sales

master cylinder brake fluid brake lines brake fluid wheel cylinders brake shoes

brake fluid calipers brake pads

wheel seals brake fluid


Figure 41 - Master cylinder kit and complete master cylinder.

Hydraulic Brake System Fundamentals Parts Technician First Period Material Identification and Calculations 270103k.

Documents

province of albertafigure

province of albertatable

braking system

courtesy allied signal

power requirements

increased system pressure

effect of speed

effect of weight