← JS4
Autopapyrus · JAC JS4 (1st generation)
https://autopapyrus.com/guides/jac/js4/rear-brake-pad-replacement/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

JAC JS4 (1st generation): Rear Brake Pad Replacement

The JS4 has rear disc brakes with a floating caliper. The job comes down to removing the caliper from its guide pins, installing new pads, and returning the piston to its original position. The exact procedure for this model is not documented in publicly available service materials, so the steps below follow the general principle for a floating caliper. Torque values are given as ranges, so check the exact figures against the manufacturer's specifications.

Difficulty: Medium Time: 1-1.5 hours Steps: 16

Parts

4
№PartAlternatives
01 JAC JS4 rear disc brake pad set (4 pads per axle) Ferodo, TRW, Brembo, Nipparts
02 Rear brake rotorsif pronounced wear lip or deep grooves
03 Caliper guide pin repair kitif not included with pads
04 Anti-squeal shimsif not included with pads

Tools

9
  • Jack and jack stands
  • lug wrench
  • socket and wrench set (usually 12-17 mm for the caliper guide pin bolts)
  • torque wrench
  • C-clamp or piston spreader tool
  • wire for hanging the caliper
  • brake cleaner
  • copper or ceramic brake grease
  • wire brush

Step by step

16 steps
  1. Park the vehicle on level ground, shift into first gear or P, and place wheel chocks behind the front wheels. Loosen the lug nuts on the rear wheel by half a turn.
  2. If the vehicle has an electric parking brake (a button instead of a lever), deactivate it before starting work. To do this, put the actuator into service mode (through the menu or a button sequence described in the owner's manual, or with a diagnostic scan tool). Do not simply push the piston in without doing this: you can damage the caliper actuator. If the parking brake is mechanical, release it and make sure the cable is not under tension.
  3. Raise the rear of the vehicle with a jack at the factory lift point, set jack stands in place, and remove the wheel.
  4. Inspect the caliper, the brake hose, and the rotor. The hose must have no cracks or leaks.
  5. Remove the two caliper guide pin bolts (usually a 12-14 mm wrench), holding the guide pin with a wrench so it does not turn. Tightening torque during assembly is approximately 25-35 N·m (18-26 lb-ft).
  6. Lift the caliper off the pads and hang it with wire from the spring or the body. The hose must not hang under load. Do not drain the brake fluid.
  7. Remove the old pads from the bracket. Note the position of the anti-squeal shims and spring clips, and take a photo if needed.
  8. Clean the bracket and the pad seats with a brush, clean the guide pins, and check the dust boots. The pins must slide freely. Lubricate them with special caliper guide pin grease. Do not let grease get on the pad surfaces.
  9. Check the rotor: thickness must be above the minimum value stamped on the rotor or listed in the specifications. If the wear lip is high, or there is runout or deep grooves, replace the rotor. To replace the rotor, remove the caliper bracket from the mount (two bolts, approximately 70-110 N·m (52-81 lb-ft), check the exact value in the specifications).
  10. Install the new pads with anti-squeal shims, matching the old ones. Apply a thin layer of copper grease only to the back of the metal backing plate and the side guide surfaces of the pads. The friction surface must stay clean.
  11. Retract the caliper piston. On a mechanical parking brake, the piston is usually screwed in clockwise with a special tool while pressing at the same time. On an electric parking brake, use only the factory service mode, in which the piston is retracted by its actuator. Before this, open the reservoir cap and watch the fluid level so it does not overflow.
  12. Install the caliper over the pads and tighten the guide pin bolts to 25-35 N·m (18-26 lb-ft).
  13. Repeat the procedure on the other wheel. Always replace pads as a set on both sides of the axle.
  14. Install the wheels and tighten the lug nuts in a crisscross pattern. Lug nut torque is usually 100-130 N·m (74-96 lb-ft), check the exact value in the specifications. Lower the vehicle and tighten fully.
  15. Take the electric parking brake out of service mode. Start the engine and pump the brake pedal several times until it feels firm. Check the brake fluid level in the reservoir and, if needed, top it up to the MAX mark with fluid of the same class (DOT 4).
  16. Test the parking brake on a slope. Then bed in the brakes: make 8-10 stops from about 50 km/h down to 10-15 km/h without coming to a full stop, then drive for several minutes without braking to let them cool.

Common mistakes and warnings

  • Brakes are a safety system
  • If you have no experience working on brake systems, have the replacement done by a repair shop
  • Do not press the brake pedal while the caliper is removed: the piston may pop out
  • Do not force the piston in on a vehicle with an electric parking brake without using service mode
  • Do not breathe brake dust, and treat the components with brake cleaner
  • For the first 200-300 km after replacement, avoid hard braking
How it works · 3D How Car Brakes Work How the part you're working on actually works — in plain English, on a 3D model. Open in 3D →