POWER BRAKES ON YOUR TRIKE

Go to your favorite shopping mall (Junkyard) and purchase a power brake booster/ from a small Toyota (Tercell).  Get a clutch slave cylinder from a Corolla.   Also pick up a small vacuum tank (looks like a black tin can)  This you tie into the intake manifold then to the booster as the VW does not make a lot of vacuum.   You can mount it out of the way using the clutch slave cylinder in line with the booster and using the normal brake master cylinder.   The rod coming out of the booster goes against the piston in the clutch slave cylinder so when you press on the brake pedal it will push against the Toyota power booster and will cause you to stop in a very short time.  Works good.  You have to just barely touch the pedal or it might throw you over the handlebars.

You can also mount it as shown in the picture