P&H T400 Outrigger Problem

[Mark Willis]

I have a 1980’s model P&H T400 and the hydraulic outriggers aren’t working right. They go out slowly and will go down but the won’t actually lift the crane. When I try to bring them up or in, they don’t do anything. Anyone know what I should check on this thing?

 

[td25c]

Engine at full RPM ?

 

[crane operator]

Directional valve not opening up fully in either direction. Stuck mostly closed but bleeds by a little on extend.

Did this happen all at once or have you just aquired a "project" crane?

 

[Mark Willis]

It is my crane. It is set up to where one valve controls the extend and retract on every cylinder. Then it goes from that valve into another valve for each individual cylinder. I have replaced the main valve that controls the extend/retract and it didn’t do any good. I had the main wiring harness replaced. I don’t know if maybe it could be the pressure relief valve isn’t working correctly and it’s bypassing it or what.

 

[crane operator]

. Does it load down the engine at all when you switch to a function, like its trying to work? Do the hoses jump at all? Does everything else work fine (that indicates whether the pump is any good).


If you suspect wiring issues, some jumper wires to a battery would be a easy way to check the solenoids/ see what is working and what isn't, much easier than a full wiring harness.

The reason td25c asked about throttle, is because a lot of cranes won't move the outriggers until you throttle it up. They will not move at a idle.

I'm not too concerned about who owns the crane, what I was asking about is if this just started, and how familiar you are with this crane. If you just got it and its been sitting a bunch, and never has worked right, usually that can be a different set of problems, than if you have had the crane for 5 years and everything else works fine, but this just stopped working.

 

[willie59]

I can't say for sure 'cause it's been many years since I've worked on the T series P&H rigs, but IIRC, they used a separate pump mounted to and driven by the engine to operate the outriggers, different pump than the main pumps that operate the crane. Sounds like you may have either a pump or main relief valve going south if it's affecting all outriggers.

 

[Paul Stoll]

I have an older P&H omega 20 while trying to move to another location on the job the outriggers quit working the engine strains when I try to operate them but nothing moves

 

[CraneMechanic73]

Weak and slow function! Check your hydraulic filters yet??