Link Belt 3400Q - Long Reach Hydraulic System Lockout Not Unlocking

[631G]

We have a Link Belt 3400Q long reach (SN:E718-9519) that sporadically will not resume hydraulic function when disengaging the safety lever in the cab. There doesn't seem to be any pattern to it. It will malfunction when the machine is hot or cold and from first start to 8 hours into shift. I thought that it might be the small switch that the lever actually moves when cycling it up and down but nothing really hanged after replacing it. I don't have a wiring diagram and given the machines age dealer support is a stretch at best. Could this be a sticking solenoid or spool possibly? I've read elsewhere that these machines weren't known to be the best on their wiring and given the intermittent nature of this issue I am leaning that way. Anyone else have this issue in the past or have any thoughts on where to look first? I am going to start looking on Ebay for shop manuals etc. see what's out there.

 

[uffex]

Good day
There appears a shortage of Link Belt schematics available, some are advertised at silly money, which I would suggest are best left collecting dust.
I suggest this solution to your issue.
With the aid of a helper switching the control lock out on/off at the pump house, you should be able to establish which solenoid valve is switching the controls off.
My method will not be every guy"s solution, however, I would hook a diode or lamp to that live cable. By pulling the fuse's one by one find the correct fuse, do not trust visual use a meter to check the current.
Kind regards
Uffex

 

[uffex]

Good day
Came across the attached may be of help.
Kind regards
Uffex

 

[gggraham]

This valve should be on the RH side , open the RH rear door. This is e pilot control block the 6 solenoids control, Swing Shut off, Pilot Pressure , Swing Brake, Fast Tracking , Power Up and Swing Cushion( Free Swing). So find out which coil is controlling pilot pressure cut off, on the Case I believe SP was the solenoid. More than likely you will find one burnt. They are all the same solenoid so just swap one.

 

[631G]

Good day
Came across the attached may be of help.
Kind regards
Uffex

Thank you for sharing. I was able to get my hands on a shop manual from Sawdustmaker and it's for a JCB of the same build. They look pretty dang close to being the same diagram. we're going to bring the machine in to the shop for a look over.

 

[631G]

This valve should be on the RH side , open the RH rear door. This is e pilot control block the 6 solenoids control, Swing Shut off, Pilot Pressure , Swing Brake, Fast Tracking , Power Up and Swing Cushion( Free Swing). So find out which coil is controlling pilot pressure cut off, on the Case I believe SP was the solenoid. More than likely you will find one burnt. They are all the same solenoid so just swap one.

Thank you for sharing this diagram. I haven't gotten into the manual I received a copy of yet but will use this diagram to compare against.

 

[David Miller]

Good day gentleman, I have the same machine with the same problem (for 4 years now) I figured out how to bypass the lockout a couple of years ago but after the machine sitting for almost 2 years I've forgotten how I bypassed it, I'd truly like to fix it correctly but would settle for temporary bypass solution as it is now in the path of an expansion at my facility ... any insight would be greatly appreciated

 

[631G]

Good day gentleman, I have the same machine with the same problem (for 4 years now) I figured out how to bypass the lockout a couple of years ago but after the machine sitting for almost 2 years I've forgotten how I bypassed it, I'd truly like to fix it correctly but would settle for temporary bypass solution as it is now in the path of an expansion at my facility ... any insight would be greatly appreciated

We’re slowly working toward getting to working on this issue. Hopefully we get to it before you have to move your machine the hard way.