these lose pressure real easily. if you use them alot they work better for sure but if they sit any lenght of time i notice they dont keep any pressure. try putting a heavy weight on the the brake peddle overnight and see if you have any more brake then before. i did this a few times in a row and evently got rear brakes to keep pressure until it set over the winter again. just a suggestion.

 

Hmmm...never had a problem with mine on my Sport 400. I don't use it, but it still works ok.