you sure about that model number? hyster didn't make an E80V that I'm aware of

got a serial number?

anyhow... if they are designed anything like the Yale electric sit down riders and i suspect they are... the parking brake mechanism is under the floorboard on left hand side, has a cable from the park brake pull handle going down to the park brake mechanism?
If you look on the front side of the park brake mechanism you will see a round **** on it... you can adjust the park brake tighter using that and this will cure your return problem. Yale trucks suffered the same problem when the park brake cables stretched some and they were constantly having to be adjusted to get them to release completely.

IF this is the design this truck has

check it out and see if I'm correct