Dump Hoist

[Believer]

On my dump trailer, I have a Dyna Jack M3551 pump. Raises fine. Doesn't want to come down--pump kind of chatters and bed won't drop at all. After several attempts, it finally works. Getting worse. Always goes up fine. Can anyone point me possible causes? Thanks.

 

[CalG]

sounds like a VALVE issue

 

[bruceatlam]

I assume that it's power up/gravity down??? If so, you have a simple solenoid valve that opens to allow the fluid to flow freely back to the tank and the hoist lowers. Agree with the prior poster --- the valve may be going bad. Or, you may have a partially broken wire in your pendant cable. That would cause momentary contact/no contact which would create the chattering --- over time you'll lose contact completely when the wire completely breaks. Simple test is to unplug your pendant and then connect the 12V post at the trailer to the "down" post with a simple jumper and see if the chattering goes away --- if it does, look for that partially broken wire in your pendant cord.