190302 aA Flashcards
T/F single hydraulic steering cylinders can be used on large equipment
False
A directional control valve can also be identified as?
Reversing valve
On articulating machines, what do we use to limit the maximum turning angle?
An external steering cushion, or stop
Why is hydraulic pressure in the steering cylinder(s) on articulating machines relieved or unloaded just as the maximum steering angle is reached?
To prevent excessive impact loads from being imposed on the steering cushions (stops)
What are two types of filters used in hydraulic systems?
Depth type and surface type
With a full-time power steering system, if the dump box is being raised at the same time that the wheels are turned and the engine rpm (pump rpm) and road speed are low, what may happen to steering speed?
The steering action may be quite slow.
After toe adjustment, what check should be done on tie rod ends?
Ensure the threaded portion is still completely inserted in tie rod split. No air gap
Before opening any part of a hydraulic system what are two safety precautions?
Ensure hydraulic system is depressurized at the tank and accumulators if necessary.
After hydraulic repairs why must the system be checked and properly calibrated if needed.
Depending on repair pressure could be too high or low possibly causing injury or damage.
One method of checking hydraulic cylinders without entering the Hydraulic system is?
A heat gun checking fitting temp and middle of the barrel temp
Upon inspection of equipment you notice there is a bolt missing out of a fastener for a pin what should you do?
Remove pin and check for integrity. Who knows how long the pin has bin loose for and could have damage resulting in pre-mature failure
During a simple visual inspection of a unit what types of potential problems are you looking for?
Frayed/crushed Hydraulic lines, scoring on cylinder rods, dust boots ripped or removed
A road test of equipment should not be performed unless?
You are familiar with the equipment and its operation, measuring devices and manufacturers specifications. As well often someone to give you a hand.
Before pressure and flow testing a price of equipment what should be done
Ensure you have manufacturers specs. Gauges are capable of handling the pressure and heat the unit will produce. Oil at the correct operating temp and proper level
A full-time power steering system is sometimes referred to as?
Hydraulic steering system or subsystem
List the components of a full-time power steering system
A reservoir, hydraulic pump, pressure control valves, priority flow control valves, steering directional control valves, hydraulic cylinder assemblies, steering cushion assemblies, and hydraulic oil filters
One or more pressure control valves may be used in a power steering system to either?
Limit system pressure thereby protecting the hydraulic pump and other components
Regulate the hydraulic pressure in a secondary hydraulic circuit
Cause hydraulic control operation to follow a certain sequence
Flow control valves can be used to?
Limit the flow rate of hydraulic oil into a particular circuit
Identify any five (5) of the steering systems mentioned in this module that are used on off-road machines with a rigid frame.
a) front wheel steering, with or without a wheel lean feature
a) rear wheel steering
b) four wheel steering: crab steering
c) four wheel steering: co-ordinated steering
d) combination steering: front or rear wheel, crab and co-ordinated steering
e) skid steering
A wheel loader uses an articulated steering system. The rear tires:
follow in the track created by the front tires.