AR42.25-B-0020-02TA | Check braking behavior on trailer vehicle | | |
OF | Test sheet on traction vehicles and trailer braking behavior, form |
1 Apply pressure stepping (pm) in the brake coupling terminal as according to test sheet and register the brake cylinders pressure (p1 to p3) and brake forces (F1 through F3) for each wheel on the test sheet. Register the lock limit.
Use "test sheet on traction vehicles and trailer braking behavior" form. Use only values below lock limit. Use the growing pressure stepping and test with high pressure, always release service brake.
If the trailer vehicle test runs with a tractor vehicle with electro-pneumatic brake (EPB/BS/EBS), (due to Inshot function), the lowest pressure to be controlled is 0.7 bar in the terminal for the brake coupling.
2 Add brake forces (F1 to F3) to individual axes and register the sum of trailer or truck brake forces (FA) related to stepping pressure (pm) on the test sheet.
3 Calculate braking (z) by stepping pressure (pm):
z = [sum of brake forces (FA)] [sum of the shaft loads allowed (GA)] 100 (%)
Example to determine the trailer vehicle braking (z):
Sum of braking forces (FA) in pm 2.0 bar = 3150 daN
Sum of the permitted shaft loads (GA) = 22,800 kg
z = (3150 22.800) 100 (%) = 13,8 %
When pressure in brake coupling terminal is 1 bar, the brake action on the wheel must already been registered.
Example brake forces ascertained: | ||
Brake coupling terminal | Complete | |
pm (bar) | FA (daN) | z (%) |
0,0 | 410 | 1,8 |
0,5 | 640 | 2,8 |
1,0 | 990 | 4,3 |
1,5 | 2150 | 9,4 |
2,0 | 3150 | 13,8 |
2,5 | 3860 | 16,9 |
3,0 | 4900 | 21,5 |
4,0 | 6700 | 29,4 |
5,0 | 7900 | 34,6 |
6,5 | BG* | BG* |
>8,5 | - | - |
* Lock limit | ||
W42.00-1028-81
4 Transfer the braking values calculated (z) for every stepping pressure (pm) from the test sheet for EG braking range. By linking points a curve is formed, indicating trailer or truck braking process (braking behavior).
If the braking process is out of EG braking range or in case of very high response pressure, it's necessary to make a complain about the brake. Trailer or truck braking system must then be verified and the ascertained failure or wear should be repaired.
Changes on braking systems are only allowed with the car assembly assignment.
2 Trailer braking process
V EG braking range, trailer loaded