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Autopapyrus · MAN TGX (1st generation)
https://autopapyrus.com/guides/man/tgx/front-brake-caliper-repair-repair-kit-replacement/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

MAN TGX (1st generation): Front Brake Caliper Repair, Repair Kit Replacement

The exact procedure for this model and axle configuration is not documented in publicly available service materials, so this is the general principle for air-actuated disc brake calipers on trucks. Before starting, identify the manufacturer and type from the number on the caliper body, because repair kits for different types are not interchangeable. If the housing or threads are damaged, it is often more sensible to install a reman (exchange) complete caliper.

Difficulty: Hard Time: 3-5 hours per side (including cleaning and inspection) Steps: 15 Tools: Jack and axle stands for the axle, wheel chocks, torque wrench, socket set and box-end wrench set, puller or special tool for pistons and the adjuster mechanism, wrench for backing off the slack adjuster (wear adjuster), copper grease and special guide pin grease, brake cleaner, micrometer or caliper, press or drivers for installing seals

Part

  • 🔩 Caliper repair kit (boots and piston or tappet seals, guide pin bushings and boots, caps, retaining rings, adjuster mechanism depending on design). The price depends on the caliper manufacturer. Brake pads and rotors are best replaced as a set per axle in this situation

Step by step

15 steps
  1. Park the tractor on level ground, shut off the engine, place wheel chocks at the rear axle, release the air from the brake system circuits, and release the parking brake according to the service manual.
  2. Lift the front axle, place axle stands, and remove the wheel.
  3. Inspect the caliper and note the markings on the housing; use them to select the repair kit. Check pad wear and rotor condition, clearances, and caliper travel.
  4. Retract the caliper by turning the slack adjuster (wear adjuster) in the reverse direction, following the procedure for your caliper type. Remove the retaining clips or springs and the pads.
  5. Disconnect the air line of the actuator (brake chamber or cylinder) if it gets in the way of removal, and plug the fittings to keep dirt out. If the actuator is not included in the repair kit, removing it is not necessary.
  6. Remove the bolts securing the caliper to the steering knuckle or bracket. These are critical bolts. Whether to use new or used ones, and the tightening torque, must follow the manufacturer's specification strictly.
  7. Remove the caliper and secure it in a vise with soft jaw protectors. Clean off dirt and rust from the outside; do not use abrasives on the mating surfaces.
  8. Disassemble the caliper in the order appropriate for its type: remove the protective caps and boots, then take out the retaining rings, pistons or tappets, and the adjuster mechanism. Lay out the parts in the order of removal and photograph the assembly.
  9. Clean the metal parts with brake cleaner. Do not use gasoline or solvent on rubber parts. Check the cylinder bores and pistons for scoring, corrosion, and wear. If there is deep corrosion or scoring, the whole caliper or piston must be replaced.
  10. Check the guide pins and bushings: the pin should slide without binding and without play. Replace worn or corroded pins and bushings.
  11. Install the new seals, boots, and caps from the repair kit. Lubricate only with the special grease supplied in the kit; do not apply mineral grease to rubber parts. Press in the boots evenly, without tilting, using drivers.
  12. Reassemble the caliper in reverse order. Make sure the pistons move freely and the adjuster mechanism turns without binding.
  13. Install the caliper on the bracket and tighten the fasteners with a torque wrench to specification. Install new pads (when replacing as an axle set), slide the caliper, and check that the pads move freely in their guides.
  14. Reconnect the air line, build up pressure in the system, apply the brake pedal several times, and check that the slack adjuster works, that there are no air leaks (using soapy water), and that the rotor spins freely.
  15. Install the wheel, tighten the lug nuts to specification, and lower the vehicle. Take a test drive at low speed: check for any binding, hub overheating, and pulling when braking. Repeat the check after the first 50-100 km.

Common mistakes and warnings

  • The tractor's brake system is a safety matter. If you have no experience with air disc brakes, leave the repair to a repair shop, especially operations involving the adjuster mechanism. Never get under the vehicle while it is supported only by a jack. After the repair, be sure to have the brakes tested on a brake tester. Replace parts in pairs per axle so that the braking force on the left and right sides is equal.
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