Parts
Car parts, explained
What each part does, the signs it is wearing out and whether you can keep driving, one page per part. Every part is in the app's 3D models, and the numbers come from them.
- Ball joint A ball joint is the ball-and-socket joint that connects a suspension arm to the wheel's steering knuckle.
- Coil spring A coil spring holds the car up. Each corner rests on one, and when the wheel hits a bump the spring compresses, stores the energy and pushes the wheel back down, while its length sets the ride height.
- Control arm US: control arm or A-arm A control arm is a hinged suspension link between the car's subframe or body and the wheel.
- Control arm bush US: control arm bushing Control arm bushes (US: bushings) are the rubber mountings where a control arm pivots on the subframe.
- Drop link US: sway bar link A drop link (US: sway bar link) is a short rod with a ball joint at each end that connects the anti-roll bar to the suspension, so the bar can resist body roll in corners.
- Top mount US: strut mount A strut top mount (US: strut mount) is the rubber-bonded mounting that bolts the top of a MacPherson strut into the car's body and carries that corner's weight.
- Shock absorber US: shock A shock absorber (US: shock) controls the spring. Without it the car would keep bouncing after every bump; with it, the body settles after one movement and the tyre stays pressed on the road.
- ABS sensor US: wheel speed sensor An ABS sensor (US: wheel speed sensor) measures how fast its wheel is turning by reading a toothed or magnetic ring that turns with the hub.
- Brake caliper A brake caliper is the clamp at each disc brake. When you brake, fluid pressure pushes its piston out and the caliper squeezes the two pads against the disc.
- Brake disc US: brake rotor Brake discs (US: rotors) are the iron discs that turn with the wheels.
- Brake fluid Brake fluid carries the push from the brake pedal to the calipers.
- Brake pads Brake pads are the friction blocks the caliper squeezes against the brake disc, turning the car's movement into heat to slow it down.
- Wheel bearing A wheel bearing lets the wheel spin freely while carrying the car's weight and the cornering and braking loads.
- Track rod end US: tie rod end A track rod end (US: tie rod end) is the ball joint at the outer end of each track rod, where the steering connects to the front wheel.
- Spark plugs Spark plugs light the compressed fuel and air in each cylinder of a petrol engine.
- Timing chain A timing chain links the crankshaft to the camshafts, so the valves open and close in step with the pistons.
- Clutch plate US: clutch disc A clutch plate (US: clutch disc) is the friction disc clamped between the engine's flywheel and the pressure plate.
- Clutch release bearing US: throw-out bearing A clutch release bearing (US: throw-out bearing) presses the clutch's diaphragm spring when you push the pedal.
- Clutch slave cylinder A clutch slave cylinder is the small hydraulic cylinder on the gearbox that releases the clutch.
See every part in 3D
Tap any part for what it does and how it fails, then take the whole assembly apart and rebuild it.
Founder pricing until 30 October
