JLG 40HA should I buy? Fixer-upper

razerface said:

no, just the servo

Click to expand...

Ok.

I'm curious if your servo does in fact have the manual engagement lever on it, some JLG models had that feature and some didn't. With the engine running, you can move that little lever and it will move the swash plate of pump in both directions. Machine wouldn't move though because brakes would be engaged, but it would load engine and hyd drive circuit. It would really be nice to know if your pump will do this.

BTW, does your new controller have 4 adjusting screws on it? Low, Mid, High, and Ramp?

yes it has the 4 adjustments. I haven't bothered them yet I am working on a pic of the servo to post.

see if pic works here,,,little flat lever is on top. Can I test it?

By golly, it does have the manual lever. I sure would like to slap that thing back on and see if it strokes the pump.


bah ha ha, I love it. Got it sitting on the box the controller from Hindley came in. LoL

yep, thats the box! you must have bought a few to recognize that plain old box!

If putting it back on is how to test it, that's what I'll do. We did take the top off. Maybe dissassemble and clean?

razerface said:

yep, thats the box! you must have bought a few to recognize that plain old box!

If putting it back on is how to test it, that's what I'll do. We did take the top off. Maybe dissassemble and clean?

Click to expand...

Yeah, I have opened a number of those boxes over the years. :tong

Well, your in an area I typically don't go. I take care of the machine components. If I determine the pump or servo is the problem, it gets sent to a pump specialist, not very familiar with the workings of the servo for this reason, I've always had tons of other stuff that needs attention and let a pump shop fix those parts.

All I'm suggesting is if we put that servo back on, operate the manual lever in both directions, and we load the engine and pump, then we know the pump is most likely good. Then we know to focus on either controller adjustment issue or possible failure of servo.

D

had a bad day trouble shooting today,,,fixed nothing in 7 hrs .

Servo--- we put it back on and worked the lever,,,nothing. We took it back off and dissassembled it,,,found nothing obvious to us,,put it back together. We did notice the post in the center was leaning to one side, contacting on side, so it only moved one way by hand. We also wondered how this works? Should there be something sticking out of the back of it of sticking out of the pump? We are worried there are parts missing. The diagram in the parts manual does not resemble our servo valve.

How do you check pressure in the drive pump? I see a QD on the end pump.

Another problem,, how do the brakes work? Does the hyd pressure put brakes on,, or take them off? We found that when we press the foot switch, the brake valve gets voltage and the hyd brake line gets hard. I think that is wrong.

razerface, I know you have spent some money on the machine to date, but it sounds to me like you need to remove the drive pump and send it off to a pump specialist. These servos and pumps are very sensative in how they are set up. I'm more than capable of working on all manner of pumps and motors, but I prefer to let a craftsman who knows those components well to perform those repairs. I think you'll be very happy with your machine operation if you get the pump fixed up.

As for your brakes, the brakes on these machines are spring applied. It takes hyd pressure to release the brakes via a solenoid valve (brake valve) and the solenoid should only operate when you operate the PQ drive controller, that's when the controller puts power on terminal 22 of terminal strip to power up brake solenoid.

thats what I thought. My brakes get powered off when I press on the foot switch! I don't even have to touch the PQ.

Why is there no p/n for the servo valve?

Is there a good pump place you know in ohio? I still want to test pressure.

Not sure why they don't provide a part number, like I said, I don't order those parts anyway. I'm certain there has to be a pump shop in Ohio, just don't know of one myself. I use an outfit in Georgia, a bit closer to me.

Yep, it appears you need to print the schematic for the platform controls and start checking your wiring, somethings wrong up there.

i checked the platform today. I seems ok. Maybe the relay down in the main? I think I have to figure out why the brake valve is working from the pedal before I will be able to check the PQ wire output,,even though it is a new controller

....dumb question,,,,deleted

Check terminal 22, should be a blk/orn wire, no other wires should be connected to it. Disconnect the Check that blk/orn goes to pin 2 at harness connector of joystick. After it goes through the connector, the wire may become a different color. If there are no other wires connected to the circuit, step on the footswitch and see if the blk/orn wire powers up. If it does, try disconnecting the blk/orn from the 16-30 cable where it connects to terminal strip at 22, may be some kind of phantom feedback from lower controls. Try it again, if this makes it right, gotta move farther down the line and find problem.

ATCOEQUIP said:

Check terminal 22, should be a blk/orn wire, no other wires should be connected to it.

Click to expand...

My schematics show 1 leg of the high engine switch also attached to #22 with a blk/orn. yours show it?

razerface said:

My schematics show 1 leg of the high engine switch also attached to #22 with a blk/orn

Click to expand...

Ahh, so it does. Told ya these things still throw curve balls at me. bah ha ha

Ok, what's happening there, the brake circuit, being powered up by the output of drive controller at terminal 22, is also being used to power the hi engine circuit. Keep in mind, the hi engine only works when boom is horizontal or lower and fully retracted.

It works like this. Operate drive controller, sends power to terminal 22 to operate brake solenoid at lower components. Blk/orn wire also comes off term 22 and goes to hi engine switch. When you select the switch to hi engine, it sends power on brn/blk wire to terminal 8 of the ice cube relay in platform box. Terminal 8 of ice cube relay is a normally closed connection to terminal 12 of relay. Terminal 12 brn/blk goes to terminal 11 of terminal strip which is high engine circuit going to lower controls. Back at ice cube relay, footswitch depressed sends power to term 14 of relay on yellow wire, term 13 and 14 operates the internal coil of the relay which switches relay. Terminal 13 is the ground (earth) for the coil, the blu/orn on 13 goes to 24 of terminal switch, which is the circuit that goes to switches on boom and ultimately to ground (earth). Whenever you extend boom or raise boom above horizontal, those boom switches provide ground for the ice cube relay at platform, switches relay, and now breaks the circuit for hi engine.

whew! had to read that a couple times!
I got my schematics and read along with you,,,it works out! It makes sense right now,,we'll see how it sounds when I have to explain it to my buddie while we are working on it.....

Do you think there is any connection to my driving problem because of the footswitch-brake valve problem? I think I'll fix that before I tear out the pump..


BTW, what does the dotted line between the footswitch and ice cube mean?

Hard for me to say on my end what's causing that problem. Disconnect that blk/orn wire that goes downstairs and work with the circuits in your platform box. That brake circuit has to be activated by the drive controller and nothing else.

The dotted line is components that are used with 0860714 and 0860715 platform control boxes. I don't know which one you have, but it's safe to say if you don't have diodes connected to terminals 43 and 44, it ain't yours.

The thing that bugs me is your drive pump servo. If you put it back on, and it won't load the pump by working the manual lever, there's something wrong. I don't know what it is, but something is wrong. I don't mess with these things, don't have much advice for ya on this, I let the experts work on pump/servo issues.

A long day of wire tracing again. I could not find anything. I decided to put the old controller back in and recheck stuff. As soon as I did that,, things healed a little. After switching and checking,, the new controller from Hindley is the problem. When it is plugged in, there is juice on terminal 22 (brake valve) all the time. So then when I stepped on the foot switch,,it triggered the brake release without moving the controller. Something is wrong with the new $300 controller.

I called Hindley. They have a new one on the way,,,,but I'm afraid that the controller may be good,,but is the wrong one for my lift. They sent me the correct p/n out of the book,,but could not identify the old one even though it has their name on it.

Will have to wait and see what the new one does.

On edit here,,,just for people to be sure,,,,I am not bitching about Hindley. As soon as I called them, they had another "on the way" and requested my serial# to further verify the controller needed for my machine thru JLG

razerface said:

A long day of wire tracing again. I could not find anything. I decided to put the old controller back in and recheck stuff. As soon as I did that,, things healed a little. After switching and checking,, the new controller from Hindley is the problem. When it is plugged in, there is juice on terminal 22 (brake valve) all the time. So then when I stepped on the foot switch,,it triggered the brake release without moving the controller. Something is wrong with the new $300 controller.

I called Hindley. They have a new one on the way,,,,but I'm afraid that the controller may be good,,but is the wrong one for my lift. They sent me the correct p/n out of the book,,but could not identify the old one even though it has their name on it.

Will have to wait and see what the new one does.

On edit here,,,just for people to be sure,,,,I am not bitching about Hindley. As soon as I called them, they had another "on the way" and requested my serial# to further verify the controller needed for my machine thru JLG

Click to expand...

That's part of why I like to deal with Hindley, they are friendly to work with and they support their product.

Keep us updated.

BTW, I will say that in nearly every case that I have replaced a PQ controller, even though it's adjusted to specs from the folks that build it, I typically find it has to be adjusted to work proper on the machine. Very rarely have I installed one and it work proper needing no adjustment. But this in not related to your controller putting power on terminal 22 when you step on foot switch, that sounds like a faulty controller. When you get your new controller and install it, try it out. If it works proper, that's good. If it has some quirks in operation let me know and I'll walk you through the process for adjusting it.