BENDIX BW2676 User Manual

External Vehicle Walkaround Air Brake System Inspection

Printed on recycled paper

Please refer to BW1971 (Advanced Troubleshooting Guide for Air Brake Compressors) for Troubleshooting Information

Date: Invoice Number: Customer Name:

Completed By:

Brake Requires Needs System Repair or Further Component Check For: OK Adjustment Diagnosis Quoted Symptom Notes/Clariﬁ cation/Impact

Compressor

Broken, Cracked, or Loose Replace Mounting Flange

Oil Leaks Exterior leaks at the gaskets. Exterior leaks at the gaskets are a sign of loose or broken parts.

Discoloration Compressor Head Discoloration or Rust Discoloration or rust can be an indication that the compressor is (See Symptom 4.0 items e, f, g & h) running hot. High operating temperatures will cause excessive

Condition of Inlet Line. A broken, bent, kinked, or restricted Inlet Line, or a A restricted inlet will cause slow pressure build and oil to pass Engine Air Filter. poorly maintained inlet air ﬁ lter or engine air ﬁ lter. into the air system. An inlet open to atmosphere and/or a poorly (See Symptom 9.0 items f & g) maintained engine air ﬁ lter will allow dirt to enter the compressor. Compressor life will be signiﬁ cantly reduced as a result.

Condition of Discharge Line Bent, Kinked, Porous or Restricted Discharge Line. A restricted discharge line will cause slow pressure build and the (See Symptom 9.0 items f & g) compressor to run hot. Compressor life will be signiﬁ cantly

Governor

Broken or Loose Mounting Replace Some governors are mounted at the air dryer. They require a Components special mounting gasket and are normally set to cut out at 130 PSI.

Exhaust Port Location The governor should be mounted so the exhaust port If the governor’s exhaust port can’t be mounted pointing down, an is pointing down. exhaust check valve may be installed to stop contamination from

Air Dryer

Broken or Loose Mounting Replace Components

The Air Dryer is Bypassed If the air dryer has been bypassed, make the necessary When the air dryer is bypassed, moisture enters the air system repairs and drain all reservoirs. and freezes. Moisture washes lubrication off of valves and creates

Heater and Wire Condition Replace broken wires. Make sure the plug is seated 12v DC or 24v DC should be at the plug when the vehicles properly. ignition is turned on. An inoperable heater will cause air dryer

Excessive Oil at Exhaust Though some oil and water is normal at the exhaust Poor maintenance will cause premature valve failure and possible Port port, excessive oil and water are an indication of poor system freeze up in colder temperatures. Never pour liquids air dryer/ compressor maintenance. (See Symptom 3.0) such as alcohol into the air brake system.

Reservoirs

Broken or Loose Mounting Replace Components

Proper Drain Cock Air leaking with the drain cock in the closed position. FMVSS 121 requires drain cocks function properly so that Operation Air won’t drain when the drain cocks are open. operation of the reservoir’s single check valves can be validated. Leakage reduces compressor life.

Drain Reservoirs

Contamination in Reservoirs Though some oil and water is normal in reservoirs, Excessive oil and water in the reservoirs takes up capacity which excessive amounts are not. In order to determine what causes the compressor to run longer and hotter leading to is excessive it will be necessary to run an the Basic Oil compressor failure. Contamination can exit the reservoirs and Passing test. The test requires the vehicle to be retested make it into the braking system. Contamination causes early at a later date. (See Symptom 4.0) valve failure and could cause loss of brakes.

(See Symptom 2.0) Excessive oil at the head gasket can indicate over pressurized

condition.

oil carry over and will shorten the life of the compressor.

reduced and could cause engine damage.

entering the port. Contamination will reduce the life of the governor.

rust. Contamination in the air system can cause brake failure.

freeze up in cold weather.

Glad Hands/Hoses

Broken / Cracked / Worn Replace A worn locking tab could cause the glad hand to come loose Condition during operation.

Contamination Clear contamination from glad hand. Make Contamination in the glad hand has a direct path to the trailer sure dummy glad hands are used when glad relay valve. Contamination can cause loss of brakes on the trailer hands are not connected. as well as the potential that the brakes won’t release and will drag.

Never pour liquids such as alcohol down glad hand lines.

Seals Worn or cracked glad hand seals should be Leaking glad hand seals can cause the compressor to run replaced. excessively, resulting in a reduction of its service life.

Valves/Air Lines

Broken or Loose Mounting Replace Components

Excessive Oil at Exhaust Though some oil and water is normal at the exhaust Poor maintenance will cause premature valve failure and possible Port port, excessive oil and water are an indication of poor freeze up. A loss of system brakes or slow brake release are air dryer/compressor maintenance. It will be necessary possible. to run an oil passing test such as the Bendix® BASIC

test. The test requires that the vehicle be re-tested at a later date.

(See Symptom 4.0)

Broken or Loose Fittings Replace Use DOT air brake ﬁ ttings. Never use regular pipe ﬁ ttings.

Air Line Condition Worn or cut air lines must always be replaced. Always use the same size and type. Replacing air lines with non-

™

Replacing ﬁ ttings with non-genuine ﬁ ttings (other than those for speciﬁ ed by the vehicle manufacturer) can cause brake imbalance.

genuine lines (lines other than those for speciﬁ ed by the vehicle manufacturer) can cause brake imbalance.

Brake Chambers

Broken or Loose Mounting Replace Components

Size The brake chamber size should match across Incorrect brake chamber size can cause unstable braking. Normally, an axle. if one brake chamber fails, the opposite brake on the same axle

Push Rod Rubbing on Push rods rubbing on the housing are an indication that Rubbing push rods can weaken and fail, or bind and bend, causing Housing the rod is not cut to the proper size. Another cause dragging brakes or brake failure on that wheel end. could be that the brake chamber is not aligned with the slack adjuster.

Bent Push Rod Bent push rods are an indication that a) the brake Bent push rods or in-operable slack adjusters will cause brake chamber push rod is not cut to size properly; or b) that dragging or brake failure on the impacted wheel end. the slack adjuster is not functioning properly.

will fail shortly thereafter.

Slack Adjusters

Broken or Loose Mounting Replace Components

Size Slack adjusters must be the same size across an axle. Incorrect slack adjuster size can drastically change brake torque on Slacks are measured from the center of the yoke to the the affected wheel end. Incorrect slack adjuster size can cause the center of the S-Cam. vehicle to be put in an out of service condition upon inspection.

Type Slack adjusters must be the identical model and Some slack adjusters function on each brake application, while others manufacturer across an axle. adjust on each brake application. Never mix manufacturers across

Stroke Check the operating stoke per the manufacturers Improper stroke adjustment can cause brake failure on the instructions. (North American Standard Vehicle Out of impacted wheel end. Improper stroke adjustment can cause the Service Criteria) vehicle to be put in an out of service condition upon inspection.

an axle.

Brake Lining Ensure the Lining is in Place Visually check the foundation brake, looking Broken parts and missing lining block may cause brake failure on the

for broken parts and missing lining block. affected wheel end. Broken parts and missing lining block can cause

Cracked, loose or missing Visually check for cracks or voids on the edge of the Cracked or missing lining block may cause brake failure on the Lining lining. Check for segments that are missing and the rivet affected wheel end. Cracked or missing lining block may cause or bolt is exposed. (See North American Standard the vehicle to be put out of service. Vehicle Out of Service Criteria)

Worn to Wear Indicator Most lining blocks are manufactured with a wear Excessive worn brake lining may cause brake failure. Excessive indicator. If the wear indicator is not present, use the worn linings can cause the vehicle to be put in an out of service Bendix® Brake Lining Wear Gauge BW7261 condition upon inspection.

Leaking Wheel Seals If the leaking wheel seal has allowed oil to leak onto the Oil soaked block will reduce brake torque, causing brake lining block, the block should be replaced on both axle ends. imbalance.

the vehicle to be put in an out of service condition during inspection.

Drums and Rotors

Visually Check for Cracks Replace Do not turn brake drums.