Code of Maryland Regulations › Title 11 - DEPARTMENT OF TRANSPORTATION › Subtitle 22 - MOTOR VEHICLE ADMINISTRATION-PREVENTIVE MAINTENANCE PROGRAM › Chapter 11.22.04 - Preventive Maintenance Standards for Freight Trailers and Freight Semitrailers › Section 11.22.04.03 - Suspension

Current through Register Vol. 51, No. 14, July 12, 2024
A. Spring and
				Attachments. Unequal vehicle height, broken or damaged spring leaves, spring
				shackles, bushings, center bolts, U-bolts, control arms, torsion bars or
				equalizers can affect vehicle steering, alignment, tracking, handling, and
				stability. With vehicle on a level surface, inspect:
Procedures:
Reject Vehicle If:
(1) Vehicle height.
(1) Uneven vehicle height permits tire or wheel contact
						  with body or suspension parts.
(2) Springs.
(2) A spring leaf is broken, damaged, or missing.
(3) Spring shackles.
(3) Spring shackle is broken, loose, cracked, worn, or
						  damaged.
(4) Bushings.
(4) Bushings are loose or missing.
(5) Center bolts.
(5) Spring center bolt is broken or missing.
(6) U-bolts.
(6) A U-bolt is broken, loose, or missing.
(7) Control arms.
(7) A control arm is bent, missing, or has a welded
						  repair.
(8) Torque arms.
(8) A torque arm is bent, missing, or has a welded
						  repair.
(9) Torsion bars.
(9) Torsion bar is loose, broken, or damaged.
(10) Equalizers.
(10) An equalizer is cracked, broken, or has a welded
						  repair.
B.
				Torsion Bar. All other suspension components shall be inspected the same as
				leaf spring suspension.
Procedures:
Reject Vehicle If:
(1) Apply brakes, slowly attempt to move vehicle. Observe
						  play in torsion bar mountings.
(1) Play exceeds 1/8 inch.
(2) Place pry bar between frame and torsion bar. Observe
						  play in rear mounting, bushing, and pin.
(2) Play exceeds 1/8 inch.
C.
				Coil Springs and Mountings. Visually inspect coil springs, control arms, rear
				torque arms, axle strut (when equipped), and front and rear stabilizer bar
				(when equipped).
Procedures:
Reject Vehicle If:
(1) Coil springs.
(1) Spring is broken or sagging and lowers a corner of
						  the vehicle more than 2 inches.
(2) Control arms.
(2) Control arm is bent, cracked, has a welded repair, or
						  bushings are loose.
(3) Axle struts.
(3) Axle strut is missing, bent, cracked, has a welded
						  repair, or bushings are loose.
(4) Radius arms (if equipped).
(4) Radius arm is missing, bent, cracked, has a welded
						  repair, or bushings are loose.
(5) Stabilizer bars (if equipped).
(5) Stabilizer bar is missing, disconnected, broken,
						  loose, damaged, or has a welded repair.
D.
				Rubber Load Cushions. All other suspension components shall be inspected the
				same as leaf spring suspension.
Procedures:
Reject Vehicle If:
(1) Apply brakes, slowly move vehicle to take up the
						  slack and inspect all attachments.
(1) Any mounting or attachment play exceeds 1/8
						  inch.
(2) Inspect all rubber pads and blocks.
(2) Rubber block is missing or rubber pad is split.
E.
				Tandem Axle Walking Beams.
Procedures:
Reject Vehicle If:
(1) Inspect rubber insert in bushings.
(1) Rubber is dispersed from bushing resulting in visible
						  movement between the bushing insert or mounting bolts or pins. Compression of
						  the rubber insert during vehicle movement is not cause for rejection.
F.
				Sliding Bogie.
Procedures:
Reject Vehicle If:
(1) Inspect condition of sliding bogie.
(1) Rail locking device or stop is missing, broken,
						  cracked, or inoperable.
G.
				Air Suspension (All Axles). Two procedures are required to inspect air
				suspension systems.
Procedures:
Reject Vehicle If:
(1) Apply air pressure and observe air pressure in
						  braking system when suspension begins to lift vehicle.
(1) Suspension begins to lift vehicle before air pressure
						  in the braking system reaches 55 psi.
(2) With normal air pressure in system, inspect: (a)
						  Bushings. (b) Pivots. (c) Lines. (d) Air bags. (e) Shock absorbers. (f) Air
						  supply. (g) Suspension height.
(2) (a) Any bushing is loose. (b) A pivot is loose or
						  worn. (c) Any line is cracked, broken, crushed, or leaks. (d) Air bag is cut,
						  has an air leak, vehicle body and chassis is unsupported, any axle or body or
						  chassis leans to one side. (e) Shock absorber, if equipped, is missing, broken,
						  or disconnected. (f) Air supply is connected to main line or wet reservoir, or
						  pressure protection valve is missing. (g) Suspension height does not meet
						  manufacturer's specification.
H.
				Air Suspension. Inspection is conducted with normal air pressure in suspension
				system.
Procedures:
Reject Vehicle If:
(1) Operate lift control and observe response of
						  retractable axle.
(1) Axle does not respond to lift control switch on
						  valve.
(2) Inspect for air leaks with retractable axle in both
						  up and down position and inspect for air pressure loss in one-way valves.
(2) Air leak is evident when axle is in up or down
						  position or there is air pressure loss at tag suspension.
I.
				Shock Absorbers (if Equipped). Shock absorber inspection includes leakage,
				mounting, and all related attachments. When originally equipped with shock
				absorbers, inspect for:
Procedures:
Reject Vehicle If:
(1) Presence.
(1) Shock absorber is missing if originally
						  equipped.
(2) Proper mounting.
(2) Shock absorber is not properly and adequately
						  mounted.
(3) Leakage.
(3) There is visible leakage. Slight dampness is not
						  cause for rejection.
(4) Condition of bushings.
(4) Any bushing is loose or missing.
J.
				Road Clearance.
Procedures:
Reject Vehicle If:
(1) Visually inspect for any suspension, frame, or body
						  parts extending below the bottom edge of wheel rims.
(1) Any part extends below the lowest point of any wheel
						  rim.