A. There is no real guidance on what brake temperatures should be for brake testing compliance. What you should be looking for is major fluctuations between wheel stations as this could indicate a fault such as a singular brake not being operational or a bind that would normally be picked up by a roller brake tester but not with a decelerometer.
Please see the below extract taken from the guide to maintain roadworthiness regarding decelerometer testing.
Section 5.3 of DVSA’s Guide to Maintaining Roadworthiness states:
It is acceptable to use an approved and calibrated decelerometer to measure overall brake efficiency values for rigid vehicles without trailers or for vehicles that cannot be tested on an RBT. A decelerometer will measure the overall brake efficiency but it may not identify individual braking issues.
A temperature check needs to be carried out before and after the decelerometer test to help identify if individual brakes are operational. Final brake temperature readings need to be significantly higher than the initial readings to properly assess the brake performance, with relatively consistent readings taken for each brake across an axle. Where satisfactory results cannot be achieved another method to assess the brake performance needs to be used.
However, if you have access to a roller brake tester we would advise that you use this method as it produces more reliable results.
No gearbox?
Q. If a vehicle has had its gearbox removed, does this mean that the tachograph needs to be recalibrated?
A. If the tachograph seal on the gearbox is broken during any maintenance works then a full calibration would need to be carried out. However, depending on the model of tachograph fitted to the vehicle you might be offered a reseal service by an authorised tachograph centre (ATC), this is not always an option and not possible with a smart tachograph.
If your vehicles experience a broken seal, we suggest speaking to an ATC.
