Hydro Dual Dump Bed

"I have a dual dump bed on a dump truck that will not come down on its own..." Sounds like it is operating properly. If it DID come down on its own, that would be a problem.

Can you perhaps expand a little bit on your information?

Equipment and age, location on the planet... those sorts of things would be useful.

What happens if you unhook the hydraulics?

Might have prop up stuck up or safety engaged....

http://www.galiongodwin.com/docs/DumpTruckOperatorManual.pdf

http://www.ptospecialties.com/troubleshoot.htm

Body prop out? Any obstruction in the pivot? Electric or manual control valves? When was the last time it was raised and lowered?

These things are normally gravity return, so any restriction in the hydraulic exhaust valve may cause the problem, as will a slightly bent ram or a confliction of the separate bodies. Sometimes, depending on the rigidity of the construction, even being on a slight lateral angle is enough to stop them dropping.

Try cracking the nut on the hydraulic line to the offending ram, if the body still fails to lower, then the problem is likely not hydraulic.

If both bodies are suffering the same complaint, and confliction can be ruled out, then look for a fault in the hydraulic common rail between the two sides.

Be aware that the body may come down in a rush so exercise great care.

Is it simply ever so slightly getting over centered by chance?

Both of our old farm dump trucks tended to do that and all it takes to bring them down once unloaded is a driving a few feet forward then getting on the brakes hard.

*Note to self. Remember to fix truck brakes some day.

Somewhere in the line from the cylinder(s) is a flow control valve to limit the return rate of flow. This is used to control the decent rate. This could have become restricted with a bit of debris. Perhaps a small piece of inner hose wall.

What has changed since it worked properly? Did this develop all at once? did it gradually get slower? Has the problem been intermittent for a while?