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Switch and a relay for the reachlift controls

oceanobob

Senior Member
Joined
Jun 13, 2010
Messages
751
Location
oceano california
Occupation
general contractor
Terex 8042 (square shooter w Terex name) has about 3k hours. Cummins powered, big heavy axles, a tilt cylinder for each side of the axle at each wheel, etc. Has been a good machine and typically pretty straightforward to work on. Now that I have it (in lieu of a new pickup: decision made a while ago), I dont know why I waited so long. Very handy machine. Collected some accessories: an adjustable boom jib, a cleanup bucket, a man basket. We once put a concrete breaker on the boom - by driving the U17 little Kubota mini onto the forks and reaching out with it to break some flatwork.

Here is the particular issue where I would appreciate a couple of suggestions.
The joystick has a center button which changes the mode of the up down of the boom to fork tilt. Said item acting indifferent, intermittent, not working.....took some of it apart, maybe it is the switch in the joystick, or the lead wires are fatigued. Switch connects to a relay, maybe that is the issue? The wires move a little every time the joystick is moved, they may not be what we call panel rated fine braided. Will try to make a loop around the handle wherein the bending is not all at the same area although the sheathe breaking off in that one section prolly was the precursor.

If I want to order and replace a new switch for the joystick, would be appreciative of how to remove the switch - a pic of the stick is shown below. Ir is not a problem to get the wires up above the deck and then spin off the handle - if that is the method.
And not related to the electrical, but I can see the seals on the four sleeve valves are in leak stage One, where they collect dirt. Are these joystick controls sent anywhere special to get new seals? Or is that something the local hydraulic shop does??
Control handle.jpeg

Then there is the relay from underneath no name only some strange acronym USA, olde skool LOL.
relay case USA.jpeg

And the relay face where the wires attach.
A terminal S that is connected to the switch in the joystick, making the coil (and it wont function unless the frame is grounded).
Numbers 3 and 2 are made to each other when the coil is energized
Relay connection.jpg

A sketch of the electrical in the relay.
Relay wiring.jpeg

After cleaning it up a bit and taping the likely exercised spot in the wires, it is back to working. But I would like to get the new parts while it is presently (temporarily) restored to order.

Many thanks in advance!
 

Txhayseed

Senior Member
Joined
Dec 23, 2019
Messages
610
Location
Texas
The joy stick should have several small screws holding it together in a clamshell fashion. Unscrew it and pop both sides away from each other. You should be able to source the Soleniod at any auto parts store. The one you got is made by cole- hersee. I say any auto parts store but most likely a napa or store that has real parts guys.
 

oceanobob

Senior Member
Joined
Jun 13, 2010
Messages
751
Location
oceano california
Occupation
general contractor
This handle looks like it was investment cast, have some other machines that do the split down the middle. Was thinking maybe i can look to see it it is Rexroth or Parker.
Then go from there.

As to the relay, will go to the NAPA store where the local farmers are seen, looked up Cole Hersee and they were bought by Littlefuse in 2010 and the relays seem like those plastic box versions.....wondering if it came with a diode or snubber? Wish there was a part number to help w cross referencing.

Thanks for the idea about the Napa store.

L8R
 

oceanobob

Senior Member
Joined
Jun 13, 2010
Messages
751
Location
oceano california
Occupation
general contractor
As best I can tell by using the part number from the mfg for the entire valve and searching .... the valve is probably a Hansa TMP HPV1 or HPV2 control valve.
A link to the Products page: https://www.hansatmp.com/manufactur...rols/HYDRAULIC_PILOT_REMOTE_CONTROL_VALVES/en


Depending on the supply chain this Joystick Control valve as entire assembly for sale is around $1k.


As fate would have it, once I cleaned that fine layer of oily dirt off the valve, I can clearly see that it weeps a little hydraulic oil. Taking this as a hint, do I replace the valve from an OEM supplier and get the new car feeling and the empty wallet, or,
remove the valve and hope there is an ID plate to get the exact part number and attempt to rebuild the unit along with a new switch for that center push button?

I have not yet been to the Napa for the relay - but that relay could be the less of the problems at hand LOL.
 

tool_king

Senior Member
Joined
Mar 29, 2010
Messages
2,145
Location
new jersey
Occupation
road mechanic owner
Terex 8042 (square shooter w Terex name) has about 3k hours. Cummins powered, big heavy axles, a tilt cylinder for each side of the axle at each wheel, etc. Has been a good machine and typically pretty straightforward to work on. Now that I have it (in lieu of a new pickup: decision made a while ago), I dont know why I waited so long. Very handy machine. Collected some accessories: an adjustable boom jib, a cleanup bucket, a man basket. We once put a concrete breaker on the boom - by driving the U17 little Kubota mini onto the forks and reaching out with it to break some flatwork.

Here is the particular issue where I would appreciate a couple of suggestions.
The joystick has a center button which changes the mode of the up down of the boom to fork tilt. Said item acting indifferent, intermittent, not working.....took some of it apart, maybe it is the switch in the joystick, or the lead wires are fatigued. Switch connects to a relay, maybe that is the issue? The wires move a little every time the joystick is moved, they may not be what we call panel rated fine braided. Will try to make a loop around the handle wherein the bending is not all at the same area although the sheathe breaking off in that one section prolly was the precursor.

If I want to order and replace a new switch for the joystick, would be appreciative of how to remove the switch - a pic of the stick is shown below. Ir is not a problem to get the wires up above the deck and then spin off the handle - if that is the method.
And not related to the electrical, but I can see the seals on the four sleeve valves are in leak stage One, where they collect dirt. Are these joystick controls sent anywhere special to get new seals? Or is that something the local hydraulic shop does??
View attachment 232303

Then there is the relay from underneath no name only some strange acronym USA, olde skool LOL.
View attachment 232300

And the relay face where the wires attach.
A terminal S that is connected to the switch in the joystick, making the coil (and it wont function unless the frame is grounded).
Numbers 3 and 2 are made to each other when the coil is energized
View attachment 232301

A sketch of the electrical in the relay.
View attachment 232302

After cleaning it up a bit and taping the likely exercised spot in the wires, it is back to working. But I would like to get the new parts while it is presently (temporarily) restored to order.

Many thanks in advance!
The handle will come apart and push button switch will be in it .You can you can replace it .I can send the manuals for the machine .
 

oceanobob

Senior Member
Joined
Jun 13, 2010
Messages
751
Location
oceano california
Occupation
general contractor
Found a few youtube videos where folks [typically with excavators] disassemble these types of valves and the seals look pretty straightforward to install.
Some comments are helpful such as: should the hose(s) be disconnected to assure not even the smallest head pressure causes those tiny valve parts to be pushed out of the valve, and to make sure to keep track/organized - 'cause there was one video showing subtle diffs on the valves and also differing springs. Which BTW he didnt do and this was puzzled out via the video author. Usual stuff too - like not labeling the hoses and mixing em up upon install etc etc.

I have a CD of the manual sent to me from the Terex Handlers and will look to determine the detail on this item. Will advise on what (detail) I find in the manual. So far: the parts list only shows one listing (for the entire valve) but maybe in some other section there could be more information.

Mentioned previously: a online dealer of Terex and Genie parts offered to sell me the entire valve (id'd for the Genie) but says it crosses back to the Terex Handlers model that I have - but the handle splits differently ..... could be a WillFit if I have to option .... keeping that as an option (far off I hope).

Local hydraulics shop (ran by a olde skool one man type) said fear not the valve upon dissassembly can be fixed up by measuring and id ing the seals and installing the new ones.
~~
For now, I determined how to activate ("jumper w alligator clips and switch") the relay for the mode change as I need the machine to finish this welding fabrication job (ground work, not overhead work).

More to follow ....
 
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