Revision to the Proper psi for Measuring Brake Stroke
| Entry Date | October 28, 2015 |
|---|---|
| Issue Number | 15-046-VEH |
| Name | Rodney Hoffman |
| Agency | Circle Bar A, Inc |
| Address | 27035 Campbellton RdSan AntonioSan Antonio, Texas, 78264United StatesMap It (opens in a new tab) |
| Phone | 830-570-8005 |
| Fax | (210) 626-2375 |
| [email protected] | |
| Committee | Vehicle Committee |
| Status | Closed |
| Summary of Issue | There seems to be conflicting information put out by the FMCSA, CVSA and the NTC compared to brake manufacturers and my home state regarding the proper pressure at which to measure brake pushrod stroke. During a recent meeting of my safety department and our mechanics, we have discovered that the proper pressure for measuring brake stroke as stated by the FMCSA, CVSA, and NTC is supposed to be between 90-100 psi. Our brake manufacturer TB's as well as the Texas State Inspection manual, however, state the proper pressure for measuring brake stroke is between 80-90 psi. Our concern is that the FMCSA bulletin dated March, 2013 states that, "a system pressure that is 20 psi...too high could .. result in a variance in measured brake stroke of nearly 1/4 inch in stroke measurement error." and that this, "may result in the inspector finding an otherwise compliant brake to appear beyond the allowable adjustment limit, resulting in an improperly assigned violation." |
| Justification or Need | If a brake mechanic is following his tech bulletins and directive from his State Inspection Program and is measuring brakes on the lower end of the proper air pressure (80-82 psi) as instructed and then the very same vehicle is inspected roadside with brakes measured at the upper end of the pressure prescribed by FMCSA and CVSA (98-100 psi), it stands to reason (according to the FMCSA's own bulletin) that there could be a variance of almost 1/4 inch in pushrod travel and result in an improperly applied violation. This could improperly affect a company's CSA score and result in compliance issues that may not exist. Basically, there may be thousands of improperly cited brake stroke violations nationwide already because of this discrepancy. |
| Request for Action | We request that CVSA consult with brake manufacturers as well as States that have a State CMV inspection programs and determine the proper air pressure for measuring pushrod stroke. We hope that CVSA will realize that the proper pressure should be 80-90 psi as instructed by the brake manufacturers. |