Just a brake testing report?
24 April 2023
Did you know that your brake test reports tell you much more than whether your vehicle has passed or failed?
Reading the reports should be a key part of your maintenance system. This means you need to know what they mean. Poorly maintained brakes may result in the loss of control of a vehicle which could obviously have terrible consequences.
In the case where your vehicle has passed the test, the results can be an early warning system. There may be things you can do to identify items that may be getting worse and need dealing with before they fail.
Vehicle Policy Specialist from the DVSA, Richard Clements, shared some top tips in the DVSA’s Moving On blog on 10 February 2022, which we discuss below.
A mine of information
A brake test report is actually a mine of information. It can tell you if various overall efficiencies such as that for service, secondary and park have been met. The report can also identify individual braking aspects where extra action is needed to avoid further problems that could result in brake failure. Some of the things that Mr Clements mentions are: bind; time lag; ovality; imbalance; and maximum force and vehicle details and weight imposed on each axle is shown on each report too.
Mr Clements poses the question: “If a report shows a brake balance across an axle only just passes, what would you do? Would you know how to find out what was causing the problem?” “You should file the report as a part of your maintenance system and any investigation or repairs should be recorded.”
Obviously, brakes are one the most important safety systems in your vehicle and should be a key part of the maintenance system. The braking performance needs checking at every safety inspection. This means they must be monitored and correctly maintained to optimise their efficiency.
A “pass” isn’t the end of the story
Interestingly, Mr Clements makes the good point that even if the brake test shows a pass, you need to look at it to identify items that may be getting worse and need dealing with before they let you down. He suggests reviewing every brake test report before putting it away and carrying out any investigation or repair work as necessary. Make sure the work is done correctly and recorded in the maintenance file. It should also be made available at the next inspection, so the technician can refer to it to check to see if has deteriorated.
Key headlines
The ‘other key headlines’ section shows the way in which your fleet is maintained and how your business is conducted.
Mr Clements suggests some key things you should be reviewing when you get your brake test reports.
This list isn’t exhaustive but offers a helpful starting point:
- are the figures in the report as high as expected? Compare them with sister trucks and/or trailers in the fleet
- is one vehicle performing differently from a sister vehicle in your fleet?
- were the vehicles loaded in a similar way and tested in the same manner?
- does the vehicle have the same type of brakes, is it maintained differently or at another location?
- are there any differences that could be a cause for investigation? If so, record your investigation and any repairs made to the vehicle
- are drivers reporting any braking issues, or were any common faults identified and subsequently repaired by the maintenance provider(s)?
He also gives some useful examples in the blog:
Possible braking defects
If axle 2 service brake on the offside shows an imbalance of 26% (offside wheel does not lock) when compared to the nearside brake effort, this indicates a possible braking defect so you would need to investigate further.
Offside brake issue
Axle 3 imbalance at 29% with no wheels locking. Although this does not exceed the limit of 30%, it indicates that there is an issue with the offside brake which requires investigation.
Vehicles with split brake systems that the manufacturer has designated as the secondary brake are not assessed as part of the brake inspection. But the brake report may show efficiency readings for these (failures for these can be ignored but this may be reflected in the service braking aspect so you would need to look into this).
How park brake efficiencies are tested
The park brake efficiencies could be tested against the design gross vehicle weight (16%) or the design gross train weight (12%). This is because motor vehicle park brake efficiency should meet the efficiency for whichever is the higher figure.
It’s worth saying that testing equipment such as roller brake testers must be maintained and calibrated to ensure the readings are accurate.
To conclude, brakes are a critical part of your vehicle, so you can’t afford to leave them without investigation when something is mentioned in the brake testing report.
A note on slack adjusters
The DVSA recently updated their guide to maintaining slack adjusters. These are a feature of brakes which make sure brakes continue to work well, even as the lining wears down.
The main issue they see frequently is where automatic slack adjusters are manually adjusted at service because they are not automatically adjusting correctly.
It’s common to read “adjust brakes” on multiple safety inspections (SIs) and then eventually the automatic slack adjuster may get replaced.
Manually adjusting the automatic slack adjuster does not fix the problem and can damage the mechanism. The correct way to maintain and check the automatic slack adjuster is covered in our updated guidance.
If you need any advice, please contact our regulatory team on 01254 828300. We also run eTraining sessions on this very subject and you can find the next session here: https://www.backhousejones.co.uk/events/
