621B TRACTOR-SCRAPER Controls Caterpillar


Controls
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1.1. Tractor Individual Wheel Brakes
2.1. Hydraulic Retarder
3.1. Differential Lock
4.1. Transmission Hold
5.1. Windshield Wiper
6.1. Light Switch
7.1. Parking/Emergency Brake Control
8.1. Cushion Hitch
9.1. Bowl - Apron (Single lever control)
10.1. Bowl
11.1. Apron
12.1. Ejector

Tractor Individual Wheel Brakes

Push handle forward to apply tractor right wheel brake.

Pull handle back to apply tractor left wheel brake.


NOTICE

Do not use individual tractor wheel brakes to steer tractor.


Hydraulic Retarder

Pull lever back to apply retarder.

Push lever forward to release retarder.


NOTICE

Anticipate the use of the retarder. Three or four seconds are needed to engage the hydraulic retarder once the lever is moved. Handle position determines the amount of retarding. The farther back the handle, the more braking action. Use the retarder at least once a week to keep seals lubricated.


Differential Lock

Depress pedal to lock differential.

Release pedal to unlock differential.


NOTICE

Do not attempt to turn the tractor when Differential Lock is applied.


Transmission Hold

Depress pedal to lock transmission in desired gear range.

Release pedal to allow transmission to shift automatically.


NOTICE

Do not downshift when Transmission Hold is depressed.


Windshield Wiper


O - OFF

L - LOW SPEED

H - HIGH SPEED

Light Switch


O - OFF

D - DASH LIGHTS

H - DASH AND HEAD LIGHTS

Parking/Emergency Brake Control


R - RELEASE


E - EMERGENCY


P - PARK

Cushion Hitch


L - LOCKDOWN


C - CUSHION RIDE

Bowl - Apron (Single lever control)


H - HOLD

L - LOWER - Push handle forward to lower apron.

Bowl


R - RAISE

H - HOLD

L - LOWER

Q - QUICK DROP

Apron


R - RAISE

H - HOLD

L - LOWER

F - FLOAT - Control will lock in this position until moved manually.

R - RAISE

H - HOLD

L - LOWER

Ejector


F - FORWARD

H - HOLD

R - RETURN

L - LOCKOUT - Control will lock in this position until ejector returns to rear, or another control is engaged.


NOTICE

Do not move ejector forward when bowl is full and apron is closed.