# COMAR Title 11 — Department of Transportation

## Subtitle 14 — Motor Vehicle Administration — Vehicle Inspections

### Chapter 04 — Safety Standards for Trucks, Truck Tractors, Commercial Buses, and Type I School Vehicles

#### Regulation .02 Steering, Alignment, and Suspension.

*COMAR 11.14.04.02*

A. Steering. Inspect the entire steering system including steering, wheel, steering column, lash, linkage, free play, and power steering for missing, loose, damaged, or worn parts.

  (1) Steering Wheel. The steering wheel shall be inspected to determine whether it is circular (complete rim) and free of cracks, breaks, or objects which will interfere with the safe steering of the vehicle. The inspection will also be made to determine whether the steering wheel is original equipment or equivalent, including diameter.

  (2) Energy Absorbing Steering Column. Some model vehicles may be equipped with an energy absorbing steering column. This special column was designed to absorb energy by controlling the collapsing of its components.  It collapses under impact from wither end of the column—steering gear end or steering wheel end. To determine whether the components are capable of functioning as designed, a careful inspection shall be performed, and include any objects on the steering column. An external examination of either shear pins or collapsible mesh-type material shall also be performed.

  (3) Coupling. On heavier vehicles, there may be a flexible coupling in the steering column located just above the steering gear, usually known as “rag joint”, “pot joint”, or “U joint”.

  (4) Lash, Free Play, and Travel. Inspect the steering system to determine whether excessive wear or improper adjustment of the linkage or steering gear exists. The vehicle shall be on a dry surface. If equipped with power steering, the engine shall be running and the fluid level and belt tension shall be within manufacturer's recommendation. (See Figure 3)

  (5) Linkage. Linkage Play. Excessive free play causes wheel shimmy, erratic brake action and steering control problems. Make sure any looseness detected is not wheel bearing free play. Spring or Torsion Bar Height. Optimum front spring height is established as part of the overall design of front wheel alignment angles.

  (6) Power Steering.

Figure 1—TYPICAL SHEAR CAPSULE LOCATION.

B. Wheel Alignment. There are five basic factors which are the foundation to front wheel alignment: caster, camber, toe-in, steering axis inclination, and toe-out on turns. All are mechanically adjustable except steering axis inclination and toe-out on turns. Overall front wheel alignment can be somewhat grossly indicated by measurement of front wheel toe. Excessive toe-in or toe-out is a general indication that a complete check should be made of all front wheel alignment factors. Rear wheel misalignment on vehicles with fixed rear suspension can be caused by broken or damaged springs, trailing rods, or center bolts and improper toe or camber adjustment on vehicles with independent rear suspension. If during road test there are no undesirable steering or handling reactions, caster and camber check is not necessary.

  (2) Caster. Caster is the forward or backward tilt, from vertical of the spindle support arm at the top. Improper caster can cause hard steering, low speed shimmy, wander, and brake pull problems.

  (3) Camber. Camber is the inward or outward tilt of the top of the wheel from vertical. Improper camber can cause erratic tire wear problems, hard steering, and wander.

  (4) Rear Wheel Alignment. The wheelbase of a vehicle with tandem rear axles is determined by measuring from the center of the front wheel to the midpoint between the tandem axles. When measuring for tracking, the dimensions shall be taken between rear wheel centers. (See Figure 8 or 9)

Figure 6—CASTER ANGLES.

Agency Note:
      
       Not applicable if vehicle specifications indicate different left and right wheel base dimensions.

Figure 8—REAR WHEEL ALIGNMENT-TANDEM BUSES.

Figure 9—TRUCK WHEEL BASE.

Figure 10 — TYPICAL BALL JOINT.

Figure 11 — PRE LOADED BALL JOINT.

Figure 12 — WEAR INDICATING BALL JOINT.

C. Suspension. Inspect the suspension system for missing, broken, damaged, worn, rusted, or modified wheel bearings, ball joints, control arms, springs, torsion bars, or frame that would affect vehicle stability.

  (1) Ball Joints. In checking for motion of ball joints, check in accordance with manufacturer's specifications, keeping in mind that the load carrying joint is unloaded in procedures(a) and (b), below, and that a pry bar pressure sufficient only to lift the weight of the wheel assembly is required. If the inspector uses the leverage of a pry bar to exert excessive pressure, he can easily force an apparent ball joint movement and get a false reading. This may result in expensive replacement of perfectly good joints.  Therefore, only a 12- to 18-inch pry bar should be used.

  (2) Ball Joint (wear-indicating). Some manufacturers provide a wear-indicating ball joint to facilitate inspection in which case a visual inspection is made with joints loaded.

  (3) Ball Joints (nonload carrying). Inspection of nonload carrying ball joints shall also be performed with the joints unloaded. With the vehicle properly jacked, inspect for any noticeable looseness.

  (4) King Pin or Spindle Bolts. Inspection of king pins or spindle bolts shall be made to determine whether there are any missing, broken, or worn parts that may affect the steering or suspension of the vehicle.

  (5) Wheel Bearings. Wheel bearings out of adjustment can cause wander, unequal brake action, and noise due to interference of parts.

  (6) Springs and Torsion Bars.

  (7) Air Suspension. Some school buses, commercial buses, trucks, and truck tractors may be equipped with air suspension systems. Inspection of the system consists of checking for air leaks, proper height and ride level.  CAUTION: The inspector should not use a creeper under the vehicle unless the vehicle is properly jacked and supported.

  (8) Air Suspension. Retractable Axle (not applicable to school vehicles). Some large vehicles may be equipped with retractable axles. If the axle is the type having independent suspension, the toe shall be checked the same as for the front suspension systems (see Figure 5).

  (9) Shock Absorbers (if equipped).

  (10) Lift Axle Air Pressure System. The lift axle shall have a certified air pressure to ensure the minimum load of 12,000 pounds for an evenly loaded vehicle with a gross vehicle weight of 70,000 pounds.

Figure 13—BALL JOINT JACKING PROCEDURE.