CVSA will put a special emphasis on suspension and steering system defects during this year's Roadcheck inspection blitz.
 - Photo: Jim Park

CVSA will put a special emphasis on suspension and steering system defects during this year's Roadcheck inspection blitz.

Photo: Jim Park

The first week of June is like spring break for many truckers, who view it as a great week to take a vacation. That's when the Commercial Vehicle Safety Alliance stages its annual 72-hour inspection blitz, called Roadcheck. For those not planning a fishing trip or a week of home renovations, CVSA will be paying special attention to suspensions and steering systems during this year's blitz.

Steering components and suspensions tend to be pretty reliable and don't require a lot of shop time, but problems can sneak up as the equipment ages. It might be safe to leave them more or less alone for the first few years, but you definitely don't want to ignore them completely.

According to Mike Beckett of Des Moines, Iowa-based MD Alignment, the average truck visiting his shop needs $1,000 worth of suspension work before he can even start doing an alignment.

"The average 3.5- to 4-year-old truck with half a million miles on it will have some undercarriage issues," he says. "We often see loose U-bolts, particularly on trucks with under-slung suspensions. The weight of the truck rest on the nut, and that stretches the bolt."

Once the bolt stretches, the axle can move within the assembly, which can cause misalignment, loose spring packs, cocked air springs and other issues.

And if guys like Mike Beckett can see loose U-bolts, so can CVSA inspectors. 

Suspension problems can be difficult to spot, as much of what matters is down below or underneath the suspension. Somebody on a creeper is in a better position to spot trouble than someone looking down from above.

Steering Violation Descriptions

OOS Violations

Non-OOS Violations

OOS and Non-OOS Violations Combined

Description of Common Issues

Steering system components worn welded or missing 259 99 358 Ball and socket joint movement, loose nuts or any welded repairs
Loose steering column 11 3 14 Caused by loose mounting components
Power steering violations 7 425 432 Leaks or power steering assist cylinder loose
Excessive steering wheel lash 5 9 14 Caused by worn steering box or loose pitman arm (in some cases) or other loose steering components
Steering wheel not secured/broken 4 1 5 Steering wheel not secured or broken
Grand Total 286 537 823  

 

Suspension Violation Descriptions

OOS Violations

Non-OOS Violations

OOS and Non-OOS Violations Combined

Description of Common Issues

Axle position parts defective/missing 287 176 463 Loose suspension tracking rods or missing spring hanger bolts or cracked spring hangers
Air suspension pressure loss 109 205 314 Leaking air bag or air line to air bag
Leaf spring assembly defective/missing 88 56 144 Broken, missing or separated leaves
Adjustable axle locking pins missing or not engaged 54 53 107 Adjustable locking pins missing or not engaged
No/defective air suspension exhaust control 0 10 10 No or defective air suspension exhaust control
Grand Total 538 500 1,038  

 

Tallies from last year's Roadcheck event list 538 out-of-service violations for suspension defects and 286 steering-related OOS violations. More than 1,000 additional violations were recorded, too, but they were classified as non-OOS. Hardly what you call an alarming number out of the 60,321 Level 1 inspections conducted during the 2018 blitz, but suspension and steering systems are pretty important.

"Steering and suspension are safety-critical systems for any commercial motor vehicle," said CVSA President Jay Thompson of the Arkansas Highway Police. "Not only do they support the heavy loads carried by trucks and buses, but they also help maintain stability and control under acceleration and braking, keeping the vehicle safely on the road. Furthermore, they keep tires in alignment, reducing chances of uneven tire wear and possible tire failure, and they maximize the contact between the tires and the road to provide steering stability and good handling."

 - Credit: CVSA

Credit: CVSA

Among the most common suspension violations was Axle Positioning Parts Missing or Defective. These include loose suspension tracking rods, missing or damaged spring hangers and spring hanger bolts. Leaking air springs or air spring air lines were next on the list, followed by broken, missing or separated spring leaves.

The most common steering related defect was Steering System Components Worn, Welded or Missing, meaning movement within the ball and socket joint of the steering king pin, any loose fasteners on steering components or any welded repairs to steering components. Loose steering columns were second on the list, followed by leaks or looseness in the power steering system. Fourth was excessive steering wheel lash (sometimes referred to as free play) caused by a worn steering box, loose pitman arm or other loose steering components.

Trailers are included in the suspension stats mentioned above, but there's another OOS defect that inspectors continue to find that somewhat alarming: sliding-axle locking pins missing or not engaged.

Proactive Inspections

 - Credit: CVSA

Credit: CVSA

Roadcheck begins June 4, so there are still a few days to get your trucks inspected for these common steering and suspension problems. Here's what CVSA recommends fleets do to ensure trucks will get successfully through steering and suspension checks:

Steering: Check the steering lash by first turning the steering wheel in one direction until the tires begin to pivot. Then, place a mark on the steering wheel at a fixed reference point and turn the wheel in the opposite direction until the tires again start to move. Mark the steering wheel at the same fixed reference point and measure the distance between the two marks. The amount of allowable lash varies with the diameter of the steering wheel.

Suspension:  Inspect the suspension for indications of misaligned, shifted, cracked or missing springs; loose shackles; missing bolts; unsecured spring hangers; and cracked or loose U-bolts. Also, check any unsecured axle positioning parts and for signs of axle misalignment. On the front axle, check for cracks, welds and obvious misalignment.

CVSA suggests drivers pay attention to the feel and handling of the vehicle and report any changes or abnormalities to the fleet.

Identifying Issues With Steering and Suspension

 - Credit: CVSA

Credit: CVSA

  • If you begin to feel more bumps and shakes as you drive, there may be an issue with your suspension.
  • Take note if your vehicle pulls to the side or makes knocking or squealing sounds during turns.
  • Pay attention to swaying and bouncing at low speeds. Your vehicle should have no difficulty withstanding bumps in the road at low speeds. If you go over a bump and feel your vehicle sway back and forth or bounce after passing the bump, the suspension may be struggling to support the weight of the vehicle.
  • Your suspension should support the weight of your vehicle and keep it fairly level during most situations. With the vehicle parked, walk around it and visually assess how level it seems to be sitting. If one side of the vehicle rests higher than the other, worn out or broken suspension components may be to blame.
 - Credit: CVSA

Credit: CVSA

Inspectors will check the following items during the inspection of the steering mechanism:

  • Steering wheel lash (free play)
  • Steering column and shaft
  • Front axle beam (including hub)
  • Steering gear box (rack and pinion, if applicable)
  • Pitman arm and output shaft
  • Upper and lower steering arms
  • Power steering reservoir
  • Ball and socket joints
  • Tie rods and drag links
  • Steering nuts

Inspectors will check the following suspension components during an inspection:

  • Axle parts/members
  • Spring hangers
  • Leaf spring assembly
  • Coil/rubber spring and air suspension
  • Composite springs
  • Torsion bar suspension
  • Suspension connecting rods and bushings
  • Other tracking components
  • Sway bar components
  • Adjustable axle(s) (locking pins, body rails, slider guides)
 - Credit: CVSA

Credit: CVSA

If you do not already own a copy of CVSA's North American Standard Out-of-Service Criteria handbook, get one. In fact, make sure you get the pictorial edition. It has nearly 100 pages of pictures (six pictures per page) of some of the horrors discovered during previous inspections. Those will stand your hair on end, but the guide is a really useful supplement to your maintenance regime in that it illustrates and describes the sort of defects the inspectors are looking for (with associated regulatory references).

It was never intended as a maintenance guide, but reverse-engineering the defect tables and the photos will bring some clarity to vehicle inspections and help drivers and technicians spot defects that otherwise may not always be that obvious to the untrained eye.

If you're not going fishing next week, good luck with Roadcheck 2019.

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