Sanwa super vortex esc brakes

[Brighton27]

Hi guys, I've got one of these esc's in my bd7 tc, and find the brakes to be pretty weak. Any advice on this?
I'm running blinky on both 17.5 and 13.5. I run trinity d4 and hobby wing v10 motors with fdr's between 3.6 and 4.2 depending on track. All indoors on carpet.
I've got sanwa mt4s radio gear so I should be somewhere near in terms of equipment.
I like all the features on the esc but I just can't get the brakes working as I think they should.
All advice is greatly appreciated guys,
Rob