Compliance Corner


The brake system on a commercial motor vehicle must work well every time, under all conditions. If not, the driver’s life and the lives of others are at risk.

To effectively stop in every braking situation, all components in the air brake system, including the foundation brakes, must be properly installed, adjusted and maintained by qualified technicians. Stroke limits specified by Canadian and U.S. regulations help maintenance technicians and enforcement personnel inspect and identify brakes that may not be properly adjusting.

During day-to-day driving, a driver cannot tell how well the brakes will work during an extreme braking maneuver. The most effective way to confirm that S-cam drum brakes are within regulatory limits is to measure pushrod stroke. Pushrod stroke is the length in inches or millimeters that the pushrod travels when the brake is fully applied. If the pushrod stroke is beyond the limit in the regulation, the foundation brake may no longer be able to provide full braking force and the brake may need servicing.

Brake system violations represent the most common reason commercial motor vehicles are placed out of service during roadside inspections. When pushrod stroke exceeds the regulatory limit, a violation exists and something may be wrong in the foundation brake system or with the slack adjuster.

By following manufacturers’ recommended foundation brake maintenance intervals (for lubrication, lining replacement, wear tolerances, etc.), regularly measuring the pushrod stroke and proactively addressing issues immediately, crash risk can be mitigated, safety ratings may improve, and the chances of a violation or out-of-service order can be reduced.

Keeping a brake chamber pushrod within regulatory stroke limits ensures there is sufficient pushrod travel to apply full force to the foundation brake under all operating conditions. The limits are based on the size of the brake chamber and whether the chamber is a standard or long-stroke design. See Clamp Type - Air Brake Adjustment Limit Chart.

Pushrod stroke that exceeds regulatory limits not only violates federal, state, provincial or territorial regulations but, more importantly, results in a decline in the braking force – eventually to zero – provided by the foundation brake, which will increase the distance it takes to stop the vehicle.

Vehicles manufactured in after Oct. 20, 1994 must be equipped with self-adjusting brake adjusters (SABAs) to automatically account for normal brake system wear. Manual brake adjusters are only permitted on legacy vehicles manufactured prior to the dates above and must be regularly adjusted by hand.

The use of SABAs has helped to significantly reduce the rate of out-of- service brake violations. However, even with properly working SABAs, abnormal or excessive wear or broken components can result in excessive pushrod stroke and must be properly serviced.

How to Correctly Measure the Brake Chamber Stroke:

To measure chamber pushrod stroke, you will need a ruler, chalk, flashlight, eye protection, pencil and paper. You will also need another person to apply the service brakes. The procedure is as follows:

Step One – Ensure the vehicle is in a safe location and make sure the wheels are properly chocked to prevent rolling. Release the spring brakes. Confirm your dash gauge indicates 90 to 100 PSI supply pressure in the air brake system reservoirs. Then, shut off the engine. Note: Supply reservoir pressure exceeding 110 PSI will result in incorrect pushrod stroke assessments.

Step Two – Visually inspect each brake and confirm it is in the normal released position with nothing wrong or out of place. Mark each pushrod to establish a reference starting location. This should be level with where the pushrod exits the brake chamber or the chamber mounting bracket. Note where the pushrod mark started out and where moves to with brake application, then measure the difference in the next step. See Measuring Pushrod Travel.

Step Three – Have the other person press and hold the service brakes (pushing the brake pedal all the way down until it stops) while you measure and record the distance each pushrod mark moved (or “stroked”).

Note: It is normal for pressure to drop slightly as brakes are applied. If multiple brake applications cause the pressure to drop below 90 PSI, pause the procedure to rebuild reservoir pressure to 90 to 100 PSI, then resume with the engine off.

Step Four – Compare your recorded pushrod stroke values with the stroke limits in the regulation for your brake chambers. See Clamp Type - Air Brake Adjustment Limit Chart.

If any chamber stroke measurement is near, at or beyond the prescribed regulatory stroke limit for your chamber type or size, the foundation brake, brake chamber, SABA, drum and wheel-end need to be inspected in more detail and serviced as soon as possible.

If any pushrod stroke measurement exceeds the prescribed stroke limit, a violation exists and braking force is greatly reduced.

Important Information and Facts Regarding Self-Adjusting Brake Adjusters

Self-adjusting brake adjusters – SABAs should not be manually adjusted; they will do so automatically. If a chamber with a SABA has excessive stroke, there is a problem with the foundation brake, the drum, the SABA itself or other components. The entire wheel end (chamber, SABA, drum, hub and other hardware) should be inspected and serviced by an authorized brake technician as soon as possible.

A manual readjustment may temporarily improve the stroke length, but it can cause damage and does not fix the underlying problem. The stroke violation will return within a few brake applications and, most importantly, stopping ability may be significantly impaired.

When SABAs exceed the regulation limit, consider the following before adjusting the brakes:

  • Drivers may be legally prohibited from adjusting SABAs in some jurisdictions.

  • The motor carrier may prohibit the driver from adjusting SABAs.

  • Do not readjust a SABA unless you have been specially trained to do so.

  • Manually adjusting a SABA improperly can damage the adjuster. The manufacturer’s instructions must be precisely followed.

  • The brake chamber will return to the excessive stroke condition until the cause of the problem is repaired. Excessive stroke can return quickly, in just a few brake applications.

  • If the driver readjusts the brake chamber stroke, he or she must continue to monitor the brake chamber stroke and report any excessive stroke problems to the motor carrier or service provider.

  • Be sure that any technician hired to correct an excessive brake chamber stroke is qualified and will fix the underlying cause.

  • If a brake chamber with SABAs exhibits excessive stroke, some of the contributing causes could include worn or seized clevis pin connections, worn S-cam bushings, cracked chamber bracket or cam tube welds, worn rollers, cracked drums, worn linings, worn drums and/or loose mounting hardware. A trained brake technician should diagnose and correct the underlying problem(s).

Charting and Tracking Chamber Stoke Travel in the Vehicle Maintenance Record

Tracking and maintaining a record of pushrod travel will help assist the fleet management in identifying brake wear periods for individual vehicles or specific routes which may cause additional brake wear.

Many fleets have found success in preventing violations by tracking brake chamber stroke measurements at each wheel as part of their maintenance programs. This involves recording pushrod stroke each time it is measured. See Stroke Travel Chart

For example, consider a truck-tractor with Type 24L chambers on the steer axle and Type 30LS on the drive axles. Stroke limits in the regulation for Type 24L and Type 30LS are 2 inches and 2 1/2 inches, respectively.

The table below shows pushrod stroke measurements recorded on three occasions. Note the circled entries show one brake at the regulatory limit (it will need service soon) and another exceeding the regulatory limit (it is a violation and must be serviced). This table can be expanded to account for all axles in a vehicle or combination.

#brakes #airbrakes #tractortrailer #FRCS #Compliance #DOT

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  • nataliefrcs

Updated: Jun 10

Memorial day has passed, and while it’s not quite yet the summer when technically speaking, the summer season is definitely upon us. With that in mind, there are a few things to remember as the weather gets warmer.

First things first, ensure that your vehicle is ready for the hot conditions by ensuring your drivers are completing Pre-Trip Inspections every day.

Remind your drivers that when checking the tires on their vehicle, they need to be sure to inspect the tire tread depths, tread separations and tire pressure. When the weather gets hot, remind your drivers to check the tires at every duty status change or every few hours or 150 miles whichever comes first.

Precautions while driving in the heat:

  • Bleeding tar:

-Tar on the road tends to rise to the surface in hot conditions, these “bleed” spots on the surface of the pavement will be very slippery.

  • Driving slowly to prevent overheating

-Driving at high speeds will create more heat for the tires and engine. In extremely hot conditions, such as desert conditions, the heat may continue to rise to a dangerous point. The constantly rising heat increases the changes of engine failure, tire failure or even fire.

Be sure your drivers are checking all vehicle fluids every day and your maintenance staff it maintaining the proper preventative maintenance intervals are strictly adhered to. Ensure all lubrication points are properly greases and all axle hubs are lubricated and sealed from leaks.

Inspecting the engine belts, it is important that the driver inspects the belts tightness on the pulley and inspect the over all condition of the belts. In addition to inspecting the belts, a driver should check the fan for damaged, missing, or cracked fan louvers.

Additionally, remind the drivers to keep an eye on the engine coolant. It is alway best practice to check this and add coolant during the Pre-Trip inspection.

Last but not least, instruct your drivers to keep and eye on the air brake system. Inspect the hoses and air lines, especially in the area of the steering axles and trailer connection points. Look for any evidence of chafing, crack though the outer reinforcement ply. All brake lines are equally important. Ensure both drivers and maintenance technicians are regularly inspecting all brake pushrod travel to ensure it is within the safety limits.

#hotweatherdriving #FRCS #DOTCompliance #summertime

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Does your company transport machinery or motor vehicles? If so, you must register the specific Hazardous Materials carried on your MCS-150 USDOT Registration.

Okay, take a deep breath and don’t panic, these requirements don’t kick in the Hazardous Materials Regulations or require special endorsement on the Commercial Drivers License. Just don’t relax too much because you will most likely need to complete and MCS-150 Update.

In some of the recent DOT Compliance Audits we have been a part of, this has been one of the biggest issues for every new company who came to us seeking assistance. The investigating officers all made issue of compliance with the MCS-150 for failing to declare the Hazardous Materials.

This requirement was introduced in March 2017 and and became mandatory on January 2018. However, over the last couple years these requirements were mostly over looked and now the FMCSA Compliance Investigators are taking a hard line and penalizing companies for getting this wrong and failing to have the correct insurance levels.

Transportation of Machinery and Vehicles with an internal combustion engine fall under these three UN Numbers:

  1. UN3528, Engine, internal combustion, flammable liquid powered or Engine, fuel cell, flammable liquid powered or Machinery, internal combustion, flammable liquid powered or Machinery, fuel cell, flammable liquid powered, 3

  2. UN3529, Engine, internal combustion, flammable gas powered or Engine, fuel cell, flammable gas powered or Machinery, internal combustion, flammable gas powered or Machinery, fuel cell, flammable gas powered, 2.1

  3. UN3530, Engine, internal combustion or Machinery, internal combustion, 9

When Updating Your MCS 150:

Section 24: Cargo Classifications

Check the appropriate fields, as follows:

Motor Vehicles

Machinery, Large Objects

Section 25: Hazardous Materials Carried or Shipped

You must select both Class 3 and Class 9 Carried in Non-Bulk.

Additionally, if your company transports these machines and vehicles in interstate commerce you will be required to meet the requirements of 49 CFR 387.7 and must have a proof of the required insurance through a signed copy of the MCS-90 for $1,000,000 on file at the motors carriers office.

Frequently Asked Questions:

1. Do CDL Drivers transporting either machinery or motor vehicles need a “H” Hazardous Materials Endorsement?

Answer: No, a Hazardous Material Endorsement is only needed when a drivers carries an amount of hazardous material which requires Placards.

2. When transporting machinery or vehicle’s am I required to display Placards for Class 3 or Class 9?

Answer: No, the placarding requirements for Non-Bulk Table 2 commodities are only applicable when the Hazardous Material carried is 1,001 pounds or more. Additionally, Part 173.220 provides an exception from all hazardous materials requirements for internal combustion engines, vehicles, machinery containing internal combustion engines, battery‐powered equipment or machinery, fuel cell‐powered equipment or machinery.

3. Am I required to have a Hazardous Materials Shipping Paper?

Answer: No, Part 173.220 provides an exception from all hazardous materials requirements for internal combustion engines, vehicles, machinery containing internal combustion engines, battery‐powered equipment or machinery, fuel cell‐powered equipment or machinery.

#Hazmat #MotorVehicles #Machinery #DOT #DOTUniversity #FRCS #Transportation

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