Ls170 auxiliary hydraulics

[B-Edwards]

I have a John Deere 7775 which is the same as a ls170/160 and wonder how you have the auxiliary hydraulics run continuously? I’ve been using a bush hog and just holding the handle down to run it and it’s killing my hand. There has to be a way to lock this on but I haven’t found it. I do not have an operator’s manual. I appreciate any help.

 

[Shanmar]

From my Deere op manual. Looks like there should be a detent when you pull handle down, but not if you push handle out.

 

[B-Edwards]

Thank you, I’ll try that and see if it works on mine. I really appreciate you posting that!!

 

[B-Edwards]

I could not get it to work, do you know if the detent is activated in the spool body or externally? I’m not sure what I’m missing as I’ve always just held it to run the bush hog but I am getting a backhoe attachment and that won’t work. I have a technical manual but not a users manual, it does not show the operation. It does show the exploded view of the valve/spool body but I still don’t quite understand what’s holding the spool/valve in the detent position. Thanks again for the help!

 

[Shanmar]

Here's some verbiage from my LS170 service manual. Maybe you already have this. It looks like the detent occurs in the cap at the back of the valve.
Maybe the linkage adjustment is off. I think I'd try unhooking the linkage and see if you can get that spool into detent by tapping on it or prying. It appears the detent direction is when pushing in. I'm pretty sure there's no lock out on that spool when the machine is not running.
I'm not going to be much more practical help as I don't use my auxiliary hydraulics and they're froze up. I've never been inside of the control valve. I see much of it is not serviced separately in parts so tread carefully.

 

[brdgbldr]

I could not get it to work, do you know if the detent is activated in the spool body or externally? I’m not sure what I’m missing as I’ve always just held it to run the bush hog but I am getting a backhoe attachment and that won’t work. I have a technical manual but not a users manual, it does not show the operation. It does show the exploded view of the valve/spool body but I still don’t quite understand what’s holding the spool/valve in the detent position. Thanks again for the help!

Most detents are held with ball bearings and springs. They work in a similar way that the detent ball on a ratchet works to keep the socket on. When the valve reaches a certain point the ball bearings are presses out by a spring into detents, or a groove, and they hold the valve in place until enough force is used in the opposite direction to compress the ball bearings and spring to remove them from the detent.

These fail in a couple of different ways. One is that the detent balls get stuck from corrosion or debris. Another is that the spring fails or gets weak.

 

[B-Edwards]

Thanks guys, I really appreciate you both taking time to help. I will investigate further and let you know if I find the problem. I’m sure it’s something simple, I’m just not familiar with how it works yet.