If you pull hard enough it reaches the handle bars but the brake efficiency is good and i know air compress no disrespect im a mechanic by trade and a former MOT tester my issue is that even after the brake locks out he continued to pull the lever until it touched the handle bars
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The MOT brake test guidelines are depressingly subjective; "hard enough" could mean anything as it could be Twiggy
or this guy doing a pull test:
Would be nice if they specified a force in, say, Newtons, to be applied for the test. You might seek the opinion of a different inspection station; maybe they'll have Twiggy on shift...
Let's stipulate that the bar shouldn't touch in "normal" use. A few things that can lead to this include:
- excessive play in the pivot; how much lost motion is there at the lever pivot
- excessive gap between the lever and the master cylinder piston; how much lever movement takes place before the piston in the M/C starts to move?
- a deformed (previously bent, not bent back properly or replaced) lever; has the lever ever been bent and if so, was it "bent back" or replaced?
- something other than hydraulic fluid is in the circuit (e.g. air), something which has a degree of compressibility
- "give" in the system when under pressure (e.g. a line aneurysm or bulge, spreading caliper body.)
- an external leak; pressure is being lost due to fluid leaking out of the circuit (e.g. past the piston seals in the caliper)
- an internal leak; pressure is being lost within the hydraulic circuit past internal seals of the master cylinder
Or or more of the above is happening in your case, mate.
These (and whatever other potential causes) aren't unique to UK-market bikes. Any hydraulic braking system can have the exact same issues.