ILM 190302 B Flashcards
What are the 5 functions of Off Road suspension systems?
Load Carrying Capacity Absorb and Transmit Torque Loads Provide operator comfort Centre the driveline Maintain ground contact
What was the hitch connection point on older scrapers called?
Stiffneck, due to no cushion hitch
What positions are available to an operator of a push pull type scraper for cushion hitch?
Bail Down with No Cushion
Bail Up with No Cushion
Cushion Ride
An operator complains that his machine has been shut off for some time, but the cushion hitch has not drained down. Why?
The valve stem on the accumulator is broken.
What type of unit would use a rubber block suspension, and where would it be mounted?
Articulated haul trucks, located on the top of the drive axle.
What 2 things do A Frames provide on an articulated haul truck suspension system?
Vertical Dampening and Longitudinal support.
What occurs on rubber block suspension when it is being used loaded and unloaded?
The rubber block will get stiffer during high loads and softer during light loads.
How does Hydrair Suspension control the rebound rate?
There is a metered orifice and a checkball that allow fluid in during compression, then the fluid returns only through the orifice.
What can happen over time on chromed rods inside the suspension cylinders?
The wiper seal will slowly destroy the chromed finish.
What are 5 reasons to perform service on a suspension cylinder?
Electronic Fault Code Poor Chromed Rod Condition Leaking cylinder or nitrogen charge Hard ride conditions Rod fully extended when unit unloaded
When measuring front suspension cylinders, what size shims are used for what temperature difference? Celsius and Fahrenheit
- 4mm shim for every 5.5 Degrees Celsius difference
0. 25” Shim for every 10 Degree Fahrenheit difference
On a large haul truck, if the pan hard rod bushings are wearing, where would the wear also show up? Why?
In the wheel bearings due to the full floating axle.
How do servo valves control the pressure within the hydraulic pump?
Spring pressure is overcome when pressure is past limits, allowing the pressure within the system to go through the spool valve and act on the swash plate, until the angle is equaled to the spring pressure.
What is a good way to test for problems within the hydraulic system?
Pull the in tank filter out, and use a magnet to check for ferrous particles.
What test is performed to determine pump condition?
A flow loss test.
