EDGE-CUTTING 2571857 - Caterpillar

Service Brake
Wheel tractor-scrapers use spring applied brakes which are released by air.
Illustration 1 g00880367
The service brakes on wheel tractor-scrapers are designed to stop the machine. The service brakes should not be used repeatedly to slow the machine partially during retarder operation.Parking Brake
Wheel tractor-scrapers use spring applied brakes which are released by air.
Illustration 2 g00872565
Pull the parking and the secondary brake control outward. This will release the air pressure and the springs will be allowed to apply the parking brakes.If the brake air pressure drops below 280 kPa (40 psi), the action alarm will sound and the parking brakes will engage automatically.The action alarm will also sound if the transmission control is moved out of the NEUTRAL position during engagement of the parking brake.Retarder
Illustration 3 g00883317
The retarder should be used for continuous speed reduction during machine operation. The transmission must be in gear in order to drive the retarder impeller.Use the retarder to control ground speed. Use the retarder on a downgrade to prevent engine overspeed.Use the retarder to help to stop the machine. The retarder will not completely stop the machine and the retarder will not hold the machine stationary.Note: Use the retarder at least one time during each work day to keep the seals lubricated.Retarding on a Downgrade
The speed selection is very important because a lower speed increases the effective force of the retarder. Generally, the speed that is used to negotiate an empty machine on an upgrade should be used for driving a loaded machine on a downgrade of the same slope. Readjust the speed after a trial run.Before you approach a downgrade, slow the machine. Anticipate the need to use the retarder. After the retarder control is moved, allow three to four seconds for the retarder engagement. Downshift the transmission to the necessary lower speed.Select the proper transmission speed that will allow the retarder to maintain a safe ground speed with little use of the service brakes.To ensure maximum cooling and the best retarding effect, select the proper transmission speed that will keep the engine speed above 1800 rpm. Do not allow the engine speed to exceed 2300 rpm. Do not allow the retarder oil temperature to exceed 135°C (275°F). Select a lower speed, if necessary.Travel at the best average speed. Do not adjust the speed up and down by using the accelerator control and the service brake control intermittently. Do not attempt all of the braking at the bottom of a hill. Keep braking steady while the ground speed is under control.The transmission hold control can be used to prevent an upshift.Attempting to stay in a lower speed on a long downgrade by using the retarder can be unsuccessful. Engine speed may increase beyond the green operating range.Use the service brakes until the speed is reduced. If additional braking is needed, pull the parking and secondary brake control outward in order to add more braking force. If proper conditions exist, you can drag the scraper bowl in order to slow the machine.Use the retarder when you are