824K Wheel Dozer, 825K Soil Compactor and 826K Landfill Compactor Machine Systems Caterpillar

Service Brake System Pressure - Test

Usage:

826K 232

Show/hide table

Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.

Always use a board or cardboard when checking for a leak.

Show/hide table

Personal injury or death can result if two persons are not used in the following procedure.

Show/hide table

NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat^® products. Dispose of all fluids according to local regulations and mandates.

Specifications

Show/hide table

Table 1
Service Brake Pressure Specifications
Date	Equipment ID Code
Pump Pressure	Setting	Actual
Service Brake Valve⁽¹⁾	Fully Depressed 5520 ± 170 kPa (801 ± 25 psi)
Service Brake Valve⁽¹⁾	Fully Released 70 ± 10 kPa (10 ± 1psi)

Show/hide table

⁽¹⁾	For both Front and Rear Brakes

Introduction

This information includes the following test:

Service Brake System

This information includes the following adjustment:

Service Brake System

Required Tools

Show/hide table

Table 2
Required Tools
Tool	Item	Qty	Part No	Description
B	B1	1	8T-0860	Pressure Gauge
	B2	1	6V-3989	Fitting
	B3	2	6V-4143	Quick Connect Coupler
	B4	1	177-7862	Hose As

Test Preparation

Position the machine on a dry, hard, level surface.
Be sure that the machine is in an open area and that the area is clear of personnel.
Place the steering frame lock in the LOCKED position.
Hydraulic oil should be at normal operating temperature 52.5° ± 7.5°C (126.5° ± 13.5°F)
Check hydraulic tank for correct oil level and maintain throughout the air removal procedure.

Test Procedure

Stop the engine. Place the transmission in the NEUTRAL position.
Engage the parking brake.
Depress the brake pedal repeatedly in order to release all oil pressure from the brake circuit.
Show/hide table

Illustration 1 g03674555

Brake control valve test ports.
(1) Test port 1
(2) Test port 2

Note: The brake control valve and test ports are located under the front portion of the cab.
Remove the protective cap from test port (1) in order to test the oil pressure of the rear service brakes. Install a 0 to 15850 kPa (0 to 2300 psi) pressure gauge.
Note: The 825K and 826K will only have a front service brake and only one test port
Look at the pressure gauge. Before you start the engine, the oil pressure must be at the pressure of the hydraulic oil tank.
Start the engine and allow the hydraulic oil to reach normal operating temperature and normal operating pressure of 52.5° ± 7.5°C (126.5° ± 13.5°F)
Hold down the brake pedal and look at the pressure gauge. The brake pressure should be at 5520 ± 170 kPa (801 ± 25 psi).
If the brake pressure is not in the correct range but the brake accumulator charging valve is functioning correctly, replace the brake control valve.
Repeat this procedure at test port (2) in order to test the oil pressure of the front service brakes.