Brake efficiency and balance is usually checked on a roller brake tester. In certain cases where a roller brake tester may not be used (for example on certain 4-wheel drive vehicles) it may be necessary to check brake efficiency and balance on a road test, with a portable decelerometer.
Inside the car
Electronic parking Brake (EPB) warning device must not be indicating a malfunction
Electronic stability control (ESC) component must not be obviously missing, damaged or inappropriately repaired or modified
ESC wiring must not be excessively damaged
ESC warning lamp must be present, working and not indicating a fault
ESC Swithch must not be insecure or faulty
A brake slack adjuster must not be defective or incorrectly installed
A brake fluid warnimg lamp must not be inoperative or illuminated
Class (v): Electronic braking system (EBS) warning device must not be inoperative or indicating a fault
Anti-lock braking system (if fitted) warning lamp is checked for:
Sequence of operation
Sufficient reserve travel on the footbrake
Pedal rubber not worn to excess
Correct operation of the servo assistance system
ABS and ESC components and associated wiring/switch checked for presence and condition
This could be hand, foot or electronically operated. Checked for reserve travel so that it doesn't reach the stops on application. The mountings will be checked for security and/or corrosion.
The brake lever or control will be a fail if:
defective or located so that it cannot be satisfactorily operated
any inappropriate repair or modification
During a decelerometer test, if vehicle deviates from a straight line when parking brake applied then this becomes a fail.
Anti-Lock Braking (ABS) and Electronic Stability Control (ESC) Systems
The inspection applies to all systems, original equipment or 'aftermarket'. Will be checked for being fitted (if originally specified), illuminating, not indicating fault, ABS to follow correct sequence.
If ABS or ESC system has been intentionally rendered inoperative the whole system, with the exception of sensor rings or other components which form part of another component.
Reasons for rejection:
component missing, damaged, inappropriately repaired or modified wiring excessively damaged
Does not illuminate
Indicates a fault
(For ABS) does not follow the correct sequence
ABS or ESC
Component missing or excessively damaged
Wiring excessively damaged
Inappropriately repaired or modified
Switch faulty or insecure
Under bonnet checks
Master cylinder and servo unit are checked for leaks with the engine on and the brakes applied
Servo unit will be checked to ensure it is operating correctly
Visible metal or flexible brake pipes will be checked for corrosion, condition, fouling or leaks
Under vehicle checks
Flexible brake pipes and any other metal brake pipes visible beneath the car are checked
Discs and drums (external only) checked for condition and contamination
Brake back plates and caliper securing devices are checked for condition and security
Condition of the brake pads will be checked if visible
The assistant operates the handbrake and the condition of the linkages and/or cables is checked.
On some vehicles there will be a brake compensating valve beneath the car which will need to be inspected for fluid leaks
All components checked for security, condition and operation.
Reason for failure:
Component inappropriately repaired or modified
Retaining or locking device insecure
Cable, rod or clevis joint insecure
A load sensing valve seized, inoperative, function impaired or incorrectly adjusted
Air brake actuator dust cover missing or not preventing ingress of dirt etc.
Brake performance check
The performance of the front and rear brakes and handbrake are checked for efficiency and balance using specialised equipment.
Horror story: Brake disc
When the owner of this vehicle dropped it off with Martin, at Discount Tyres in Sittingbourne for its MOT, they mentioned a noise which had been coming from the front of the vehicle when braking.
Martin offered to carry out an inspection of the brakes but the owner declined and asked only for the MOT to be done.
When driving the vehicle in for test, Martin noticed the ABS light was on. When carrying out the underside inspection, he couldn't see a brake disc on the nearside front, so decided to abandon the test.
The picture shows what Martin found when he removed the wheel.
Martin abandoned the test as he felt it wasn't possible to complete all aspects safely. A decision we can't argue with. Obviously in situations like this, conducting a brake test would be out of the question.
If the rest of the test can be completed, without risk of further damage or injury, then the reason for rejection 'Item not tested' (RfR 3.7A1), could be used to fail the vehicle, along with a note that a brake test was not conducted.
Luckily this owner made it to their MOT before suffering more serious consequences.