My rear maggie is playing up,  I run a Monty X-Lite wheel and rimjam blues,  I press the lever once and it stays on the rim there is nothing on my rim that makes it stick,  I can pull the brake pad away from my rim then press my lever again and it does exacly the same  :( ,  Any tips on how to get my maggie fully functional again? 
 
Please help 
 
Cheers,