AI · 8 cards

Brake Systems flashcards

8 cards with the formulas, rules and traps from this lesson. Answer in your head, then flip to check.

Formula · 1/8
Pascal's principle in brakes: how do pressure, force and piston area relate?
$P = \frac{F}{A}$ . Pressure is the same everywhere in one circuit, so output force $F_{2} = P \times A_{2}$ ; a bigger piston gets more force. Example: 400 N on 5 cm² gives 80 N/cm², so a 20 cm² caliper piston gets 1,600 N.
Formula · 2/8
How does the force ratio of two brake pistons depend on their diameters?
$\frac{F _{2}}{F _{1}} = (\frac{d _{2}}{d _{1}})^{2}$ because area grows with diameter squared (the $\frac{π}{4}$ cancels). A 2 cm master and 5 cm caliper piston give 6.25 times the force.
Formula · 3/8
Kinetic energy the brakes must remove: formula and speed effect?
$K E = \frac{1}{2} m v^{2}$ (m in kg, v in m/s, KE in joules). Energy goes with speed squared: double the speed means 4 times the energy and heat; 4 times the speed means 16 times.
Formula · 4/8
Braking distance at constant deceleration (no reaction time)?
$d = \frac{v ^{2}}{2 a}$ , d in m, v in m/s, a in m/s². Tripling speed makes d nine times longer; doubling a halves it. Example: 25 m/s at 6.25 m/s² stops in 50 m.
Term · 5/8
What is the master cylinder's job in the brake force path?
It is where hydraulic pressure is first created: the pushrod drives one or two pistons that trap fluid and force it into the lines. Modern tandem units feed two separate circuits so one leak leaves partial braking.
Rule · 6/8
Brake pedal feel: what do a spongy, a hard, and a firm-but-weak pedal suggest?
Soft or spongy pedal: air, boiling fluid vapor or a leak. Very hard pedal needing big leg force: lost booster assist. Firm pedal but the car slows less after heavy use: friction fade from overheated pads and rotors.
Common trap · 7/8
Does ABS guarantee a shorter stop? How should the driver brake with it?
No. ABS mainly keeps wheels rolling so the driver can steer; on gravel or deep snow a locked wheel may stop shorter. Press firmly and hold; do not pump. Pulsing in hard stops is normal ABS action.
Common trap · 8/8
Disc versus drum: which parts go with which, and can DOT 5 replace DOT 3?
Disc: caliper, pads, rotor. Drum: wheel cylinder, shoes pushed outward, backing plate, return springs. Shoes never press a rotor. DOT 5 is silicone and must not be mixed with glycol DOT 3, 4 or 5.1; use the fluid on the cap.

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