Foot Brake Control Pedal Assembly Caterpillar

Foot Brake Control Pedal Assembly

Usage:

WHEEL LOADERS

INTEGRATED TOOLCARRIERS

WHEEL TRACTORS

SOIL COMPACTORS

LANDFILL COMPACTORS

950G (2JS, 3JW, 4BS, 5FW, 5MW, 6NS, 8JW),
962G (3BS, 4PW, 5AS, 5RS, 6EW, 6HW, 7BW),
966G (3PW, 3SW, 3ZS, 8XW, 9RS, AAH),
972G (1EW, 4WW, 6AW, 7LS, 9GW, AAW),
980G (2KR, 2SR, 9CM),
IT62G (6PS, AKP),
824G (2HP, 4SN),
825G (4JP, 6RN),
826G (2GP, 7LN))

Problem:

The foot brake control pedal assemblies on the machines listed may be binding or out of adjustment. This can cause the service brakes to not disengage completely when the foot pedal is released, resulting in residual service brake pressure and causing the brake taillights to remain on. The residual service brake pressure can cause overheating of the axle oil. Axle oil overheating causes rapid axle oil degradation, higher then normal iron contamination, poor service brake life, poor axle bearing life, and poor axle gear life.

Solution:

If any of the problems listed above are found, check to see if the foot brake pedals are binding, or are improperly adjusted.

Service Brake Control Valve (Typical Example)

(1) Upper pressure tap.

(2) Lower pressure tap.

Check the residual service brake pressure by attaching a hydraulic pressure gauge to the upper pressure tap on the service brake control valve that is located under the cab. Use a 6V-7830 Tetra Pressure Gauge, or a 7580 kPa (1100 psi) pressure gauge. If neither of these gauges is available, only partially apply the brakes. Start the machine. Depress one of the brake pedals and release it slowly. Binding may only occur during a slow release of the brake pedal. When the brake pedal is released, the service brakes should be open to allow oil flow back to the hydraulic tank.

Hydraulic tank residual pressure is normally zero to 34 kPa (5 psi). If the residual pressure exceeds zero to 34 kPa (5 psi) check the adjustment of the foot pedal assemblies.

NOTE: 950G, 962G, 966G, 972G, 980G Wheel Loaders, IT62G Integrated Toolcarriers, and 824G Wheel Tractors are equipped with a service brake control valve that is biased to separate the front axle service brake system pressure from the rear axle service brake system pressure. The upper port of the service brake control valve will produce 206 to 345 kPa (30 to 50 psi) of hydraulic pressure before the lower port of the service brake control valve produces hydraulic pressure. This hydraulic pressure difference will remain until the service brakes are fully released. When checking for residual hydraulic pressure always check the hydraulic pressure at the upper port of the service brake control valve. The 825G Soil Compactor and 826G Landfill Compactor are equipped with a single-stage service brake control valve and only front axle service brakes. Use the single pressure port to check the residual hydraulic pressure.

If the service brake residual pressure exceeds zero to 34 kPa (5 psi) perform the following checks.

(3) Foot pedal shaft assembly.

(4) Left foot pedal base.

View A-A

(5) Pedal heel stop adjustment

1. Check both of the foot pedal heel stops and adjust as needed. If the heel stops are extended too high, the service brake control valve will not release.

2. Check the shaft assembly between the left and right pedal bases for interference with the lower steering shroud fastener. If the shaft is rubbing against the lower steering shroud fastener, remove the fastener and grind it shorter to clear the shaft assembly.

3. Check for binding of the shaft assembly between the left and right foot pedal bases. If the shaft assembly is binding, loosen the three left foot pedal base bolts. Reposition the left foot pedal base to eliminate the binding. Tighten the bolts to 28 ± 7 N·m (21 ± 5 lb ft). Check again for binding at slow release.

NOTE: Do not lubricate the pedal pivot pins. Petroleum products can damage the nonmetallic sleeve bearings.