CONSOLE-FRONT 2525109 - Caterpillar

AIR CHAMBER AND MASTER CYLINDER OPERATION
1. Air chamber inlet port from brake valve. 2. Piston. 3. Boot. 4. Air chamber assembly. 5. Spring. 6. Supply port. 7. Cap. 8. Bypass port. 9. Master cylinder assembly. 10. Master cylinder outlet port. 11. Cylinder head. 12. Plate. 13. Cup. 14. Indicator rod. 15. Piston. 16. Passages. 17. Valve. 18. Cup. 19. Spring. 20. Valve and seat assembly.Wheel Cylinders - (81J1 Thru 81J4509 And 31K1 Thru 31K1054)
The wheel cylinder assemblies convert oil pressure into mechanical movement to actuate the brake shoe assemblies.
WHEEL CYLINDER ASSEMBLY CONSTRUCTION
1. Boot. 2. Piston. 3. Cup. 4. Spring.Wheel Brakes - (81J1 Thru 81J4509 And 31K1 Thru 31K1054)
BRAKE ASSEMBLY (Right front wheel illustrated)
1. Shoe assembly. 2. Cylinder assembly. 3. Link assembly. 4. Spring. 5. Brake backing plate.Depressing either brake pedal sends brake fluid from the master cylinder to the wheel cylinder assembly (2) and forces link assemblies (3) against shoe assemblies (1). The shoes are forced against the brake drum. After the brake pedal is released, spring (4) returns the brake shoes to their original position.Wheel Brake Assembly - (81J4510-Up And 31K1055-Up)
Hydraulic pressure in the head (1) acts on discs to provide wheel braking. The discs revolve with the wheel hubs and the head is mounted on the axle flange. The head has two pistons and a friction pad, bonded to a metal backing, on each side of the disc. The pads and backing are held in place by anchor pins. When the brakes apply, oil pushes the piston and pads out against the disc.
DISC BRAKE COMPONENTS (Typical example)
1. Head assembly. 2. Anchor pin. 3. Friction pad. 4. Metal backing. 5. Piston. 6. Disc.
To prevent damage to pistons and seals, do not apply brakes when brake pads are removed.
Oil flows through lines and drilled passages to all pistons within each head assembly.
HEAD ASSEMBLY (Disc Brakes)
1. Head assembly. 2. Anchor pin. 3. Friction pad. 4. Metal backing. 5. Piston. 7. Bleed valves. 8. Line. 9. Piston seal. 10. Anchor retaining bolt.When the brakes are applied, the hydraulic pressure balances the pistons and the force exerted on each side of the disc is equal. The pistons do not have return springs.The pads may be replaced, without removing the head, by removing the anchor pin and sliding the pad out.
Do not apply brakes with pads removed. The pistons must not be allowed to extend out of their bores with the pads removed. Open the bleed valves on the head to relieve any pressure acting on the pistons. If the pistons should extend and expose the seals, head removal will be required to reinstall the pistons.
Two bleed valves on each head are used to bleed the air from the hydraulic brake system. Bleed the brakes whenever a line is disconnected in the hydraulic brake circuit.Parking Brake - (81J Thru 81J3501 And 31K1 Thru 31K942)
The parking brake is an internally expanding shoe brake mounted on the front of the transfer drive case. The parking brake acts on the brake drum secured to the