I've got a buddy with an 00 ford 450 dump and he has trouble with the box lowering when it's raised. I can't remember the type of dump body but he says if he raises the box about 8-12 inches it will lower fine. Once it gets any higher, it takes a long time for it to come down. I was thinking it would be one of the solenoids on the dump valve but I have not seen the truck or worked on alot of dumps. any help is gratly appreciated.

Power down or Gravity down?? Probably gravity down if it does come down but slow the solenoid is working and either has the pressure screw to tight on the valve/pump or it has DRY hinges and is binding..

Power down or Gravity down?? Probably gravity down if it does come down but slow the solenoid is working and either has the pressure screw to tight on the valve/pump or it has DRY hinges and is binding..
I agree, he may also maybe going right to the pivot point and the bed is balancing on the hinges. I have seen older dump beds do this with a good size head board. Just a thought anyway.

I agree too, but i had a front break hose on p'up truck that was bad and acted like a one way valve. It would not let the pressure back to the master cylinder. So it could be a hydraulic hose that has a split inside acting as a one way restrictor.

Just a suggestion.

I Had The Same Problem On A 450 1996 Mason Dump Electric Pump With Gravity Down The First Problem Was The Scissor Lift Was Set In The Wrong Place It Did Not Lift More Than 5.5 Tons And My 1997 With The Same Bed Does Up To 8 Tons Not A Legal Weight But My Idiot Guys Have Loaded This Heavy. Also Keep The Pins Greased If Not Completely Rusted Than Clean Or Install New Pins And Keeped Greased. We Cleaned The Pins And Greased Them Regularly And Every Once In A While I Had The Same Problem So I Drove And Hit The Breaks And The Bed Started Moving Down And Then Did Not Have The Problem After It Started Moving. Sorry But Probably Was Installed In The Wrong Place By The Body Company And Just Does Not Have Enough Weight To Drop Down