Hand brakes

[Terry]

In your latest article you state that a hand brake must be mechanicaly operated and a hydraulic line-lock is not allowed.This being the ruling of the MOT,why is then that HGVs operate by allowing a no mechanical system to operate there hand brakes ie a valve which drains air from the system and allows the springs operating the brake shoes to bind onto the brake shoes.Surely if air is non mechanical then so is fluid? :confused: Terry .Merlins Riders

[excalibur]

On air brakes, they are mechanical. It is the spring, which is mechanical, which holds the brakes on, the air which releases them.

It is a non mechanical method to release the brakes, not apply them.

[xjtriker666]

av ya ever seen a 32 ton trike....dont think so.....mechanical hand-brake is ..if ya av a hydraulic failure then ya hand-brake still works...............thats wot i was told at m.o.t place...an i aint gerrin into yea but ppl can tek ya hand brake off .the law states.an thats it.................

[Terry]

Hello as HGV driver for many years( Fire Brigade) l do understand quite how air brakes work, perhaps l didnt make it quite clear its the actual opperation of the system.i.e. that a non mechanical operation ,opening a vale that drains the system,it is air and not mechanical that allows the springs to press against the brakes.Terry thanks for your comment though