Dump bed troubles


LawnSite Member
I need information, everyone I talk to has no idea what what the problem is. I have a 1997 GM 1 ton cab chassis truck. It has a 9' Knapheide brand dumping flatbed with an electric pump. The platform raises and lowers fine, the problem is, after its lowered and resting tightly on the subframe it raises 1/2 inch within 5 minutes, weather the truck is parked or driving. Then when its a 1/2 inch of the frame it constantly bounces. Also, if someone could recommend a place to service the dump bed in the Detroit metro area, I would really appreciate it.


LawnSite Member

I'm not exacltly sure whats wrong with your truck. Its probably a valve not closing or something like that.

As far as a place to service, there is Metro truck and repair (off of I-275) but I think that they service big stuff.

I know that NBC Truck equipment in Roseville sells/services dump bodies. I couldn't comment on their service though.

Hope this helps a little...



LawnSite Bronze Member
Somerset, NJ
Just a wild guess & along the lines of a bad valve. Maybe there is too much oil in the reservoir. The bed lowers but somehow the overflow oozes back into the piston under pressure (through that valve that may be bad?) and it raises a little? Good luck getting to the bottom of that one.


LawnSite Fanatic
Flint, Michigan
Scotty, It sounds like you have a sticky valve, but it's sticking closed. You probably only have power up since it's an electric motor to your hydros. (Automatic transmission probably) The valve should able to stay open to allow the bed to rest. Like BRL said, it's very possible you have too much fluid in it too. Contact Jursik Truck Equipment there in Detroit. They are PROBABLY the ones who built the truck since it is a Knapheid. Not too many people sell those. High quality though.