I have taken the V2 model apart after it stopped working. Essentially the same type things in that model as in the model in the photo here.

I did use WD40 to clean it up. Worked well.

I found my problem. The white plastic pieces need lubrication so that they moved easier when somebody steps on the pedals. Once I got everything lubricated correctly it worked like a charm.

Not easy to put the springs back though.