Code of Maryland Regulations › Title 11 - DEPARTMENT OF TRANSPORTATION › Subtitle 22 - MOTOR VEHICLE ADMINISTRATION-PREVENTIVE MAINTENANCE PROGRAM › Chapter 11.22.03 - Preventive Maintenance Standards for Multipurpose Passenger Vehicles and Passenger Buses › Section 11.22.03.05 - Brake Systems - Hydraulic and Vacuum

Current through Register Vol. 51, No. 14, July 12, 2024
A. Parking Brakes.
Procedures:
Reject Vehicle If:
(1) Apply parking brake using driver's manual
						  control.
(1) Application of parking brake fails to hold the
						  vehicle stationary.
(2) Application.
(2) Parking brakes do not fully apply and release when
						  driver's control operated.
(3) Control accessibility.
(3) Parking brake control cannot be reached from driver's
						  seat.
(4) Holding power.
(4) Operating mechanism fails to hold brakes in applied
						  position without manual effort.
(5) Mechanical components.
(5) Any component is seized, missing, incorrectly
						  installed, loose, broken, or worn to such extent as to restrict the
						  effectiveness.
B.
				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 below
						  1/2 inch of top.
(3) Cap.
(3) Cap is missing, vent holes are plugged, or gasket
						  missing or damaged.
C.
				Brake Failure Indicators. Visually inspect:
Procedures:
Reject Vehicle If:
(1) Warning indicator.
(1) Lamp fails to operate when ignition switch is in
						  start position, or lamp operates continuously.
(2) Pressure differential switch.
(2) Lamp comes on with engine running and brake pedal
						  depressed as hard as possible.
D.
				Brake Pedal Reserve and Leakage Test. Without pumping or repeated brake pedal
				applications, apply a moderate foot force to pedal and maintain for 1 minute.
				Inspect:
Procedures:
Reject Vehicle If:
(1) Leakage.
(1) Pedal moves slowly in applied direction.
(2) Travel.
(2) Depressed height is more than 75 percent of total
						  possible travel or does not meet manufacturer's specifications.
(3) Pedal pad.
(3) Pedal pad is loose, broken, or missing (if fitted by
						  manufacturer).
E.
				Hydraulic System with Hydraulic Assist. Vehicles equipped with an electrically
				driven hydraulic pump that functions in the event of a power steering failure
				may be checked by applying pressure on the brake pedal and turn the ignition
				switch from "off" to "on" position.
Procedures:
Reject Vehicle If:
(1) Apply moderate pressure to brake pedal and turn
						  ignition switch on and off.
(1) No assist in service brakes is detected.
(2) Visually inspect brake warning indicator (if
						  applicable).
(2) Brake warning indicator fails to function when assist
						  pump is not operating.
F.
				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.
G.
				Power Brake Operation.
Procedures:
Reject Vehicle If:
(1) With engine off, deplete all vacuum from system.
						  Apply moderate pressure to brake pedal and start engine.
(1) Brake pedal does not move downward when engine is
						  started.
(2) Visually inspect brake booster.
(2) Booster is loose or damaged.
H.
				Vacuum Reserve.
Procedures:
Reject Vehicle If:
(1) Start engine and build full vacuum. Shut off engine
						  and make one brake application.
(1) Reserve is insufficient to make one full brake
						  application.
(2) Inspect operation of low vacuum indicator.
(2) Indicator fails to operate when system is reduced to
						  8 inches Hg vacuum.
I.
				Vacuum Pump (if Applicable).
Procedures:
Reject Vehicle If:
(1) If the system is not equipped with a vacuum gauge,
						  attach a gauge between the pump and reservoir and operate the pump. If the
						  system also uses engine vacuum, disconnect and plug engine vacuum source.
(1) Vacuum pump is not capable of maintaining 18 inches
						  Hg vacuum.
J.
				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 §J(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
						  §J(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 inch greater than the original inside
						  diameter.
K.
				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, visually inspect for
						  cracks or 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 §K(2). Otherwise remove only the wheel where
						  the defect is suspected. When wheels are removed, perform the inspections
						  specified in §K(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
						  anti-vibration components.
(7) Caliper is leaking, fails to operate, 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.
L.
				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 connections are not double flared.
M.
				Master Cylinder. Visually inspect master cylinder for:
Procedures:
Reject Vehicle If:
(1) Fluid level.
(1) Any reservoir fluid level is more than 1/2 inch below
						  top of reservoir.
(2) Leaks.
(2) There is evidence of a fluid leak.
(3) Damage.
(3) There is evidence of damage.
(4) Mounting.
(4) Master cylinder is not securely mounted.
(5) Cap.
(5) Cap is missing, has plugged vents, or gasket is
						  missing or damaged.