Thanks for your interest in the VPM-1.
We don’t do anything to the actual pedal hardware. On the 20 or so units that I’ve modded on used Ernie Ball VP Jr pedals, all of them seem to behave properly…the treadle stays in place when it’s set in one position. It sound’s like your VP Jr may be too worn out to use this way. When I get some time I’ll take the treadle off of one of them and see if there is any adjustments that can be made to tighten the axel up.
-Brach