Brakes
Scope
Brake work on the G1 covers inspection, pad and rotor replacement, caliper service, hose and line condition, drum brakes, parking brakes, ABS components, and hydraulic diagnosis. Safety and cleanliness matter as much as diagnosis.
Concepts you must own
- Fluids: DOT 3, DOT 4, and DOT 5.1 are glycol-based and hygroscopic. DOT 5 is silicone and must never be mixed with glycol fluid. Follow the cap.
- Rotor service: measure thickness with a micrometer and compare to the minimum stamped on the rotor. Below minimum means replacement, not resurfacing.
- Caliper service: clean and lubricate slide pins, inspect the piston boot, and support the caliper so the hose is not stretched.
- Pedal diagnosis: a low or spongy pedal suggests air, a leaking component, or rear drum adjustment; a hard pedal suggests a booster or check valve fault.
- Bleeding order follows the manufacturer, typically starting at the wheel farthest from the master cylinder.
- ABS: a wheel speed sensor fault can disable ABS and set a brake warning lamp without any base brake symptom.
Traps
Do not let a caliper hang by its hose. Do not push a dirty piston back without considering the ABS hydraulic unit; opening the bleeder can prevent forcing contaminated fluid upstream. A pull under braking is usually a sticking caliper or a collapsed hose, not an alignment fault. Pad squeal at low speed may be normal for a given friction material; metal-on-metal grinding is not.
Worked example
A vehicle pulls left only when the brakes are applied and the right front wheel is hot after a short drive. A sticking right caliper is dragging. Inspect the slide pins and piston, replace or rebuild as needed, then flush fluid and road test.
Rule of thumb
If measured rotor thickness is at or below the stamped minimum, replace the rotor.