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Anyone know JCB telehandlers? Steering problems....

bgaidan

bgaidan

Red Skull Member
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NC Triad
I'm looking at an early 2000's 520. Seller is a forklift shop/dealer and says the machine in stuck in crab steer. Said his mechanic changed or rebuilt the steer cylinders and apparently died before getting it fully back together and his other mechanic(s) don't have the knowledge and/or time to diagnose it. He said he thinks it's a sensor or something relatively minor. 3,000 hour machine, former sunbelt rental. A little rough on the finishes, but claims no cylinder leaks and engine runs perfectly.

Sound familiar to anyone? Easy-ish fix?

I've never dug in to a 4 wheel steer machine like this so I'm only speculating on how they work. I assume they just have extra solenoids for the rear steer cylinders that operate opposite the front for 4 wheel or with the front for crab, or not at all. Possibly a sensor that tells them when they're centered for when you're in front wheel steer?


It's a decent enough deal to what similar age and condition machines sell for that I could spend a grand or two on fixing it and still come out a ahead. Just don't want to get in to something that requires tearing the whole machine apart that parts aren't available any more.



I was close to making a deal on the same model but about 10 years older and it had the exact same steer problem, but the machine itself was also completely roached out so I walked on it.
 
Worst case scenario I'd like to think you can flip some hoses around and have it stuck it 4 wheel steering mode, which is where every one I've ever driven has been left in just about permanently
 
I’ve worked on several telehandlers and other crab steer equipment. That model doesn’t ring a bell, and I’m not recalling any of the specifics of JCB’s steering system from 23 years ago.

Steering type is an electronic selection. (Unless that machine predates that, and it shouldn’t.) It’s nothing a service manual with a wiring diagram can’t fix. This dealers mechanics must all be under 30 if they can’t figure it out. That or idiots.

There are no sensors for “center”. No sensors at all on the steering. Just an electronic valve body to choose the mode, attached to a basic hydrostatic power steering system. Easy peezy.
 
D Nelly said:
Worst case scenario I'd like to think you can flip some hoses around and have it stuck it 4 wheel steering mode, which is where every one I've ever driven has been left in just about permanently
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That was my thought. Worst case, I would think I could get the rears back to center and just run front steer.

IH Man said:
I’ve worked on several telehandlers and other crab steer equipment. That model doesn’t ring a bell, and I’m not recalling any of the specifics of JCB’s steering system from 23 years ago.

Steering type is an electronic selection. (Unless that machine predates that, and it shouldn’t.) It’s nothing a service manual with a wiring diagram can’t fix. This dealers mechanics must all be under 30 if they can’t figure it out. That or idiots.

There are no sensors for “center”. No sensors at all on the steering. Just an electronic valve body to choose the mode, attached to a basic hydrostatic power steering system. Easy peezy.
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520 is one of the relatively small machines....llike 4.4k capacity, I think. The newer models are like 520-40, 520-50, I believe.

1710169006883.png

Google pic, not the actual machine I'm looking at.

Pretty sure you're right on electronic selection. I don't know this exact machine, but I believe they have a 3-way switch that selects betweeen 2 wheel, 4 wheel and crab. I just wasn't fully sure how that switch actually translates to the hydraulics - I'd assume just swapping solenoids around.


So no sensors at all? So if you want to go from 4 wheel or crab back to 2 wheel or whatever, you just manually center the rear wheels and hit the switch? If that's the case, I have far less concerns about being able to trouble shoot and rig something.



I talked to the owner this morning. Sounds like his lead mechanic just suddenly dropped dead and he was left in a bind. Kind of sounds like he makes more money on selling regular warehouse type lifts and took this in on a trade and just wants to get rid of it. But he's also trying to sell it to me so take that for what it's worth. :laughing:
 
I had a '98 212SU that had a lever to switch from 4WS to 2WS or crab steer.

I'd axe if their isn't just a lever.
 
bgaidan said:
So no sensors at all? So if you want to go from 4 wheel or crab back to 2 wheel or whatever, you just manually center the rear wheels and hit the switch? If that's the case, I have far less concerns about being able to trouble shoot and rig something.
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Correct. I've worked on machines that had a dash gauge that indicated center. I've also worked on machines that you had to look for yourself. Never worked on one that had auto center, and definitely not in 2001.
 
JD Mark said:
I had a '98 212SU that had a lever to switch from 4WS to 2WS or crab steer.

I'd axe if their isn't just a lever.
Click to expand...
Levers were common for a long time. Not sure when the switch to electronic was made.
 
Fuck those modes.

If you're buying/modding this for yourself, just set it up so the steering wheel steers the fronts, and add a stick to control the back, just like a rockcrawler.

Then you have every mode all the time without cranking the fucking wheels to line up with the proxy switch so it'll switch modes, or cranking the wheels until they're straight then flipping the switch.

Saves on tires and gives way, way more better and smoother control.

I use a JCB4CX backhoe at work all the time, with a man basket on the front and when trying to follow a curvy rock wall underground it'd be awesome to leave the fronts straight and just steer with the rear like a forklift. Lots of times rear only steer would be handy, but it's not available as a standard "mode". Would be especially handy when the boom is telescoped way out there.
 
IH Man said:
Correct. I've worked on machines that had a dash gauge that indicated center. I've also worked on machines that you had to look for yourself. Never worked on one that had auto center, and definitely not in 2001.
Click to expand...

Yeah, that manual center is a PITA. After plowing for awhile, I'd be crab steering. Trying to get it just right sucked.

Might be because I'm a tad OCD.
 
Muckin_Slusher said:
and add a stick to control the back
Click to expand...
That's not a simple thing to do. Not on a machine that complex. It would be harder to cluster fuck it up like that than to fix it, or even modify it so that you could rear steer it only.
 
JD Mark said:
Yeah, that manual center is a PITA. After plowing for awhile, I'd be crab steering. Trying to get it just right sucked.

Might be because I'm a tad OCD.
Click to expand...
Lol, me too. I can tell when it isn't tracking perfectly straight and I have to stop and fix it. Really annoying.
 
IH Man said:
That's not a simple thing to do. Not on a machine that complex. It would be harder to cluster fuck it up like that than to fix it, or even modify it so that you could rear steer it only.
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Ditch the mode valve stuff, rs spool valve plumbed before the steering valve. Sure rs will have priority flow but not a big deal. Worst part would be pulling all the old stuff.
 
Dethmachinefab said:
Ditch the mode valve stuff, rs spool valve plumbed before the steering valve. Sure rs will have priority flow but not a big deal. Worst part would be pulling all the old stuff.
Click to expand...
I’m not sure you understand how these are plumbed.
 
JD Mark said:
I had a '98 212SU that had a lever to switch from 4WS to 2WS or crab steer.

I'd axe if their isn't just a lever.
Click to expand...
IH Man said:
Levers were common for a long time. Not sure when the switch to electronic was made.
Click to expand...

This one's an '05. I'm looking at the equipment sites and auctions trying to find a good pic of the controls. You may be right as I'm not seeing the switch I thought was on the dash. I think the back lever is the steer select
1710170683087.png


IH Man said:
Correct. I've worked on machines that had a dash gauge that indicated center. I've also worked on machines that you had to look for yourself. Never worked on one that had auto center, and definitely not in 2001.
Click to expand...
This one is an '05. I kind of expected it to at least have a sensor/indicator for center. And if it does, I kind of suspect that could the the problem of what it won't come out of crab.


Dethmachinefab said:
It's a steer switch and a solenoid bank. Good chance of a bad wire or dead coil. Id not be afraid to buy it.
Click to expand...
Yeah, I'm 99% sold. I'm just waiting for him to get me a freight quote to see what the final price would be to get it up to me. Pretty sure I'll be in to it for maybe 60% of what comparable machines are selling for so I'll have a good cushion to fuck around.
 
Moar pics of controls
1710170929646.png

1710171032046.png

1710170947615.png


Can't find a good pic of any control diagrams or one of the dash showing if there's a center indicator.

I'm guessing front two levers are boom control, middle is aux and rear is steer select?
 
Dethmachinefab said:

3-MODE STEER, SWITCH & HARNESS - CONSTRUCTION JCB 520-50 - LOADALL 520-50, 9802/7820, M754000- ELECTRICS-MACHINE, CAB & ENGINE ELECTRICS, CAB 3-MODE STEER, SWITCH & HARNESS | 777parts

3-MODE STEER, SWITCH & HARNESS - CONSTRUCTION JCB 520-50 - LOADALL 520-50, 9802/7820, M754000- ELECTRICS-MACHINE, CAB & ENGINE ELECTRICS, CAB 3-MODE STEER, SWITCH & HARNESS | 777parts
777parts.net
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Good find.
I'm assuming you have access to that site? It's blurred out for me and wants me to make an account. :flipoff:

Any chance you could copy/past the diagram or post some screen shots? Does it show you the price on the harness/switch?


1710172085995.png
 
bgaidan said:
Good find.
I'm assuming you have access to that site? It's blurred out for me and wants me to make an account. :flipoff:

Any chance you could copy/past the diagram or post some screen shots? Does it show you the price on the harness/switch?


1710172085995.png
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Na, that's as far as I got as well. Can probably call up a jcb dealer and get them to email you the breakdown to "order the right part"
 
My dad has a JCB of a larger model than that.

Coincidentally, it has very similar issues. All the wiring going into those spool valves seems to be about 10 times more complicated than it needs to be, but it can be sorted out.
 
Dethmachinefab said:
Na, that's as far as I got as well. Can probably call up a jcb dealer and get them to email you the breakdown to "order the right part"
Click to expand...
Fucking annoying how hard OEMs make it to even find the most basic information on shit like this.

Can't even find a basic operator's manual. :shaking:
 
Definitely electronic - the steering axle has a centering prox switch.

store.kdplant.com

JCB Steering Proximity Switch | 701/60075

OEM genuine proximity switch / sensor for JCB Loadall steering axle | Fitted to: JCB 3CX 4CX 520 525 526 528 530 533 535 540 | Part number: 701/60075 701/80227 701/42100
store.kdplant.com store.kdplant.com
 
Yotota said:
Definitely electronic - the steering axle has a centering prox switch.

store.kdplant.com

JCB Steering Proximity Switch | 701/60075

OEM genuine proximity switch / sensor for JCB Loadall steering axle | Fitted to: JCB 3CX 4CX 520 525 526 528 530 533 535 540 | Part number: 701/60075 701/80227 701/42100
store.kdplant.com store.kdplant.com
Click to expand...

Sweet.

Seems like it'll all be easy enough to troubleshoot and/or mickey mouse. :laughing:
 
bgaidan said:
Sweet.

Seems like it'll all be easy enough to troubleshoot and/or mickey mouse. :laughing:
Click to expand...

That looks like a sweet little telehandler. I saw quite a few with buckets too which would be super useful - it could be worth finding a used bucket if you have a need for it.
 
I always wanted one of those small ones, just couldn't justify it.

I already have too much equipment not being fully utilized.
 
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