brakes

MOT checks for motorcycle brakes are divided into three sections. Please click on a link below to skip to the section of interest.

brake controls :: brake systems :: brake performance

Brake Controls

  • Motorbike breaking systems must have two methods of operation fitted and functioning
  • All controls, mountings and fastenings must be secure and in good repair
  • All pivots must be within reasonable levels of wear tolerance
  • All controls must be easy to apply and have adequate reserve travel on application
  • Hydraulic systems must not creep* under load or feel spongy when applied

*creep: Fully depress you break lever and hold it firm. If, over time, its resistance grows less and it slowly allows you to add more and more pressure, this is called creep. It most likely means you have a leak somewhere in the hydraulic system of that brake.

Modifications

The VOSA handbook says that an MOT certificate should be refused if any ‘deliberate modification’ has significantly reduced the original strength of a load bearing member or it’s supporting structure.

Pre-1927 Motorcycles

Motorcycles which were first registered before 1st January 1927 only need to have a braking system which works on one wheel, not both.

Brake Systems

  • All security or locking devices such as split pins, lock nuts etc must be present and secure
  • Standard brake pads or linings must be at least 1.5mm proud of their backing plates
  • Sintered brake pads or linings must be at least 1mm proud of their backing plates
  • Hydraulic reservoirs must be securely mounted, capped and sealed
  • Hydraulic reservoirs must have sufficient fluid in them

Other reasons for brake systems failing the motorcycle MOT

  • Excessively worn, corroded, cracked or in any other way damaged cables, levers, rods and linkages
  • Insecure or cracked drums or discs and missing securing bolts
  • Too much free play on levers through wear or poor adjustment
  • Contamination of brake pads by oil or grease
  • Insecure backing plates, reaction brackets or calipers
  • Leaking master cylinders or brake pipes/hoses
  • Brake pipes which can be easily fouled or trapped by other moving parts of the motorcycle
  • Inadequately supported rigid pipes/hoses
  • Excessively chafed, twisted or kinked brake pipes/hoses
  • Disc scoring, pitting or wear
  • Excessive brake disc run out* or distortion

*run out: whilst the bike is moving very lightly apply each of the brakes in turn and slowly increase pressure. If you can feel a slight pulsing whilst doing this, that is run out. It is caused by warped or uneven wear in your motorbike’s discs.

note on brake hoses: damage to the protective sleeves of brake hoses will not necessarily fail the bike MOT provided the pipe or hose to which it is attached is not damaged. Cracking or chafing must be severe enough to expose the hose reinforcement to be considered a fail.

note on movement of discs: many discs fitted to modern sports motorcycles are ‘fully floating’ which means they are designed to have a certain degree of movement. If in doubt consult a qualified motorcycle MOT test technician, do not assume that some movement in your disk is an MOT fail. The tester may, at his discretion, take your bike for a brief road test.

Brake Performance

Reasons for your motorbike’s brake performance failing the MOT

  • Sticking or binding brakes
  • Severe grab or judder
  • Braking effort which is inconsistent with the amount or pressure applied at the lever
  • Excessive fluctuation of brake effort when steady pressure us applied
  • At least one brake must achieve 30% efficiency* with the other at least 25%

*efficiency is calculated by the motorcycle MOT computer system using this formula:

Efficiency (%) = (Retarding Force ÷ Weight) x 100

The total retarding force is measured using either a VOSA approved brake tester and Weight is the combined weight of the motorbike plus motorcycle MOT test technician. In the case of linked or dual braking systems the retarding force is the total from both wheels when operated by the dual control only.