Colin Moss's Chassis Flashcards
Tires and Wheels
Tread depth of 5/32 minimum
Tread damage or debris
Tread wear is even
Sidewall damage (bulges, cuts)
Valve stems are tight, not damaged, and caps in place
Adequate air pressure, within 10 PSI of other tires
Duals not touching and no debris between
Wheel cover is tight
Wheel not bent or cracked
Bead is not damaged
Rust or black streaks around lug nuts may indicate a broken stud or loos nut
Check hub oil
If time, tilt the cab to get a better view of the tire
Under front bumper
Loose or missing bolts and broken welds on bumper mounts
Damage to gravel pan and proper mounting
Properly Secured air horns, siren head, and wind up
Damage to low hanging parts like front intake piping
Steering Assembly
Loos linkages
Hydraulic oil leaks
Loose or missing bolts
Broken mounts
Identify Parts (starting closest to the steering wheel)
Steering linkage
Steering gear
Pitman arm
Steering arm (check for excessive play at joints)
Tie rod ends (check for damage and excessive play)
Center link
If time, tilt the cab to get a better view of the steering assembly
Front or Rear Springs
Broken springs
Loose U-bolts
Springs shifting on axle
Broken center pin
Spring hangers
If time, tilt the cab for a better view of the springs
Front or Rear Brakes
Grooves or cracks in rotors
Pad thickness
Properly secured brake cans
Oil Leaks
If time, tilt the cab to get a better view of the front brakes
Front or Rear Quick Release Valves
Quick release valves are used to send appropriate amounts of air to the brakes. They are also the link to the system anti-lock brake system. They are the device that pulses the air to the cans to keep from skidding.
Check for:
Loose air lines
Tight wires
Proper mounting
Engine
Check for:
Damage to pan
Oil leaks
Check with cab tilted:
Oil leaks
Tight connections
Proper oil fluid levels
The ECM is the brain for the engine and the pressure govenor.
Check for
Loose or damaged Wiring
Oil leaking onto ECM and wiring
Proper mounting
Air Dryer
This removes moisture and other contaminates after the air is compressed and prevents freezing in the system. It will be located between the air compressor and the air tank.
Once the system has reached maximum pressure, the air dryer will “purge”, removing fluid from the system and expels it onto the ground. This is an audible loud hiss of air. Usually happens after the engine has had time to run for a few minutes.
Check for:
Excessive oil leaking from bottom
Good hose and wire connections
Proper mounting
No cracks or damage
Cab-tilt Motor and Reservoir
Check for:
Proper oil level
Loose wiring and hoses
Leaks
Proper mounting
Transmission
Check underneath for:
Oil leaks around bottom and rear seal
Good Cooler line condition
Tight yoke and u-joints
All bolts and caps in place
Proper mounting
Check above for:
Loose wires
Proper oil level (check while engine is warm and running)
Diesel Particulate Filter System
This system acts as the muffler and also traps particulate matter from the exhaust.
Check for:
Signs of exhaust leaks
Damage
Proper mounting
Driveline Yoke, Universal Joint and Slip Joint
Check for:
Play in the U-joint
Bolts missing from u-joint caps
Excessive grease being flung out, indicating a bad seal or over greasing on slip joint
Signs of excessive movement
Frame Rails and Cross Member
Check for:
Cracks
Loose bolts
Wires hanging out from the wire looms
Wires being chaffed from rubbing on frames
Carrier Bearing
The carrier bearing is what supports the driveline and helps reduce vibration when it has a long span.
Check for:
Excessive movement up and down and side to side by pushing on driveline beside it.
