Electric/Hydraulic dump bed not lowering

[Chris van Duyvendyk]

Story: I have a 5500 with a Electric/Hydraulic dump bed (NOT PTO). This is a power up gravity down system. The bed used to go up and down without issue and was used often. i have never had any issues and maintain often. After one of my deliveries the bed just did not go down, it just stopped. I ended up cracking the hydraulic line to lower the bed. it has been awhile since this happened and just recently had time to replace the relay/solenoid thing the controller is attached to and the controller. the bed still goes up but no matter the angle or weight (that ive applied not about to put 4 yards of soil in and attempt to lower while im between the bed and truck frame) (this last raise I probably had 1 yard of soil in it. yes i have emptied it and tried with no weight)

Symptoms: Bed goes up but no matter what angle it is at it does not go down. when hydraulic feed line is loosened the bed lowers but spills oil everywhere.

What I have tried: Replaced the Controller and replaced the "solenoid" (the thing the controller is plugged into)

Recent Changes Before Issue: 1 month ago i replaced the reservoir due to a crack in the neck. filled with new oil. old oil looked relatively clean as i replace fluid every 3-4 months. while replacing also greased all hinges (grease every month)




Please not that this is not my truck but its the same type of lift (cant recall the name)
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Sorry if this is repeated somewhere I was looking threw posts and havent been able to find exact same. ive read threw similar but those said to replace either the solenoid or the controller which i have done

 

[B.G. Smith]

There would be a "solenoid" or heavy duty relay to operate the pump. There is probably a failsafe valve at the cylinder where the hydraulic line is tied in. This would be to prevent the load from falling if the hose or line fails. That device will have a wire or wires running to it to release the fluid and lower the load.

 

[Chris van Duyvendyk]

this is a pic of my system. yes there is oil everywhere i just added a little oil before lowering so i could raise it again later as you can see the solenoid has been replace this box was welded while me new reservoir is being shipped. to lower i have been loosening the hose at the top of the pump. I assume you would be talking about the part attached to the side of the pump just below the pressure line?

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[B.G. Smith]

The picture didn't make it, but yes if there is not something where the line ties into cylinder then the thing at the pressure hose is it. bg

 

[Hoefler]

There is a solenoid that is for reurning fluid to the resevoir, is it getting power, is it grounded, etc..