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 11.22.04.04 - Brake Systems - Hydraulic and Vacuum

Current through Register Vol. 51, No. 14, July 12, 2024
A. Brake Lines and Hoses. Visually inspect:
Procedures:
Reject Vehicle If:
(1) Lines and hoses.
(1) Any line is cracked, chafed, flattened, insecurely
						  mounted, restricted, any repairs other than steel tubing (tubing connections
						  shall be double flared), leaking, or welded.
(2) Master cylinder.
(2) Master cylinder leaks, is loose, or fluid level is
						  below 1/2 inch of top.
(3) Cap.
(3) Cap is missing, vent holes are plugged, or gasket
						  missing or damaged.
B.
				Vacuum System.
Procedures:
Reject Vehicle If:
(1) Visually inspect lines, hoses, clamps, and
						  connections.
(1) There are any missing, broken, collapsed, chafed
						  lines, hoses, clamps, or connections.
(2) Visually inspect vacuum tank.
(2) Tank is leaking, loose, or damaged.
(3) Clamps.
(3) Any clamp is loose, missing, or broken.
C.
				Drum Brakes-Hydraulic.
Procedures:
Reject Vehicle If:
(1) Apply a moderate force to the brake pedal for 1
						  minute. Then check all brake drum and backing plate exterior edges for evidence
						  of brake fluid, oil, or grease leakage.
(1) Brake fluid, oil, or grease is evident at exterior
						  edge of any backing plate or brake drum.
(2) If the backing plate or brake drum has inspection
						  holes, visually inspect thickness of brake lining.
(2) The brake lining thickness appears to be 1/16 inch or
						  less.
(3) Visually inspect exterior surfaces of backing plates
						  for damage.
(3) Any backing plate is bent or damaged.
(4) Visually inspect brake drums for cracks.
(4) Any brake drum is cracked.
(5) Removal of all wheels and brake drums on an axle is
						  only required when a rejection occurs under §C(2). Otherwise only remove
						  the wheel and brake drum for the wheel where the defect is suspected. When
						  wheels and brake drums are removed, perform the inspections specified in
						  §C(6)-(10).
(5) (Rejection not applicable in this step)
(6) Bonded Lining. (a) Measure thickness of lining at
						  thinnest point. (b) Inspect lining condition.
(6) (a) Thinnest point of remaining bonded lining is 1/16
						  inch or less. (b) Bonded lining is broken, cracked, loose, missing, wear is
						  extremely uneven, or lining is contaminated with oil, grease, or brake
						  fluid.
(7) Riveted Lining. (a) Measure thickness of lining at
						  thinnest point above rivet head. (b) Inspect lining condition.
(7) (a) Thinnest point of remaining lining above a rivet
						  head is 1/16 inch or less. (b) Lining or rivet is broken, cracked, loose,
						  missing, wear is extremely uneven, or lining is contaminated with oil, grease,
						  or brake fluid.
(8) Mechanical Components.
(a) Visually
						  inspect self-adjusters.
(b) Visually inspect self-adjuster cables
						  or mechanisms.
(c) Anchor pins and hold-down springs.
(d) Visually inspect backing plate.
(8)
(a) Self-adjuster is missing, seized,
						  inoperable, not for proper side of vehicle, or extremely worn.
(b)
						  Cable or mechanism is missing, broken, loose, or inoperable.
(c)
						  Any pin or spring is missing, broken, loose, or extremely worn.
(d) Backing plate is worn, bent, or damaged to prevent free movement of brake
						  shoes.
(9) Wheel Cylinders.
(a) Inspect for
						  operation.
(b) Inspect for leaks.
(c) Inspect dust
						  seals.
(9)
(a) Any wheel cylinder fails to operate.
(b) Any cylinder leaks.
(c) Any dust seal is missing,
						  damaged, or deteriorated.
(10) Brake Drums.
(a) Visually inspect for
						  damage and cracks.
(b) Measure inside diameter of drum for wear
						  and remachining.
(10)
(a) Any drum contains cracks in the
						  friction surface which extend to the outer edge of the bore, or any drum
						  contains any external cracks.
(b) Any combination of wear and
						  remachining exceeds the brake drum manufacturer's limits. If a limit is not
						  available, the maximum combination of wear and remachining may not exceed 0.090
						  inch greater than the original inside diameter of the drum if the original
						  diameter of the drum is 11 inches or less. For drums greater than 11 inches
						  inside diameter, the maximum wear and remachining may not exceed 0.120 greater
						  than the original inside diameter.
D.
				Disc Brakes-Hydraulic.
Procedures:
Reject Vehicle If:
(1) Apply a moderate force to the brake pedal for 1
						  minute. Then check all calipers and rotor (disc) surfaces for evidence of brake
						  fluid, oil, or grease leakage.
(1) Brake fluid, oil, or grease is evident or visible on
						  accessible surfaces of any caliper or rotor (disc).
(2) If brake linings are visible, visually inspect
						  thickness of lining.
(2) Brake lining thickness appears to be 1/16 inch or
						  less.
(3) If rotors (discs) are visible, or visually inspect
						  for cracks damage.
(3) Any rotor (disc) is cracked or damaged.
(4) Removal of all wheels on an axle is only required
						  when a rejection occurs under §D(2). Otherwise remove only the wheel where
						  the defect is suspected. When wheels are removed, perform the inspections
						  specified in §D(5)-(8).
(4) (Rejection not applicable in this step)
(5) Bonded Linings.
(a) Measure thickness of
						  lining at thinnest point.
(b) Inspect lining condition.
(5)
(a) Thinnest point of remaining lining
						  is 1/16 inch or less.
(b) Bonded lining is broken, cracked, loose,
						  missing, wear is extremely uneven, or lining is contaminated with oil, grease,
						  or brake fluid.
(6) Riveted Lining.
(a) Measure thickness of
						  lining at thinnest point above rivet head.
(b) Inspect lining
						  condition.
(6)
(a) Thinnest point of remaining lining
						  above a rivet head is 1/16 inch or less.
(b) Lining or rivet is
						  broken, cracked, loose, missing, wear is extremely uneven, or lining is
						  contaminated with oil, grease, or brake fluid.
(7) Calipers. Visually inspect leaks, operation, and
						  operate, anti-vibration components.
(7) Caliper is leaking, fails to or piston is
						  seized.
(8) Rotors (Discs).
(a) Visually inspect for
						  damage and cracks.
(b) Measure thickness of rotor for wear and
						  remachining.
(8)
(a) Any rotor is broken, cracked into
						  the hub, or friction surface cracks extend to the periphery of the rotor.
(b) Any combination of wear and remachining reduces the thickness
						  of the rotor to less than the minimum thickness established by the manufacturer
						  or that stamped on the rotor.
E.
				Brake Lines and Hoses-Hydraulic.
Procedures:
Reject Vehicle If:
(1) Visually inspect lines and hoses for condition,
						  mounting, restrictions, and proper material and repair.
(1) Any line or hose is leaking, cracked, chafed,
						  flattened, restricted, welded, insecurely mounted, replaced with other than
						  steel tubing, or connections are not connections are not double flared.