electric brake fix ?

my JCB hedge trimmer model is fitted with a electric brake device to the motor ,when you release the trigger the blades used to stop almost instantly,this function has now stopped working and the blades now run on for a fair bit before stopping (no braking effect )

how do i cure the electrical braking to to the motor problem, is the capacitor across the switch the problem or is it there to prevent arcing on the switch contacts