Help with "Three Point Limiter" on a K-600 backhoe.

[dchimirev]

I have a K-600 3pt backhoe on my L245. It's got a hydraulic three point limiter which is disconnected from any hydraulic lines and the cylinder itself looks pretty shot. I'm totally new to game and the only thing I know about this setup is what I found on another forum. I'd love some expect advice/opinions on what I need to do to get this feature back to operating condition. Also how bad is it to use the backhoe as is. I've included some pics for reference.

Also here the post from the other forum:

"The shaft end of the cylinder attaches to the heavy duty 3-point hitch top link close to the tractor's top link bracket.

The other end of the cylinder attaches to the center of the backhoe frame at the very bottom. Therefore the cylinder points up from the bottom of the backhoe frame towards the back of the tractor at "about" a 45 degree angle.

This cylinder is single action, i.e. it only has one hydraulic port, and can only forced by hydraulic fluid to extend the shaft. The hydraulic hose attached to this port simply goes directly to a "tee" in the hydraulic source (pressure) hose that provides hydraulic fluid flow (powers) the backhoe.

The way it works is this: If the backhoe is just sitting there doing nothing, the hydraulic fluid simply flows through the source and return lines at low pressure, and the limiter cylinder sees virtually no pressure. In this case you can raise/lower the backhoe with the 3-point hitch mechanism and the limiter cylinder will not resist. If you are using the backhoe and apply down pressure to dig, the pressure rises in the hydraulic source hose and the limiter cylinder extends, pushing the rear of the tractor up and the backhoe frame down."

 

[North Idaho Wolfman]

It's important, get it fixed.

Three points do not have down pressure so without it working there is no pressure other than its own light weight on the BH.

 

[dchimirev]

Does anyone know where/how the Three Point Limiter Cylinder hook into the hydraulics? It was disconnected when i got the tractor and I can't seem to find a hose that would connect to the cylinder.

 

[100 td]

Have a read of post #3
http://www.tractorbynet.com/forums/attachments/260989-kubota-k-550-k-600-a.html

 

[shootem604]

The link is where he quoted from...

I just bought a 4520 3pt backhoe (Woods BH640 made for Kubota). It didn't come with that option at all - just a heavy duty toplink, so I am trying to replicate the Woods Saf-T-Lok kit in the short-term while I design a subframe. I just played around with it as is, and there is way more movement than I am comfortable with - I would say it is not safe to use without the limiter or some braces or something.

I've attached a pic of the Woods Saf-T-Lok rigid toplink system.

I did look at buying another brand of backhoe that basically replaced the toplink with adjustable (bolted) heavy duty square tubing, and had your typical adjustable toplink running at a 45 down from a bracket at the tractor end of the tubing to a bracket at the bottom of the backhoe for rigidity. Can you just replace your hydraulic limiter with a toplink?

 

[100 td]

The link is where he quoted from...

I only read his post #3 where he asks where to hook it in. He mustn't have read his own post, or he doesn't understand how a tee fits in a line. There could be a tee in the line or at the valve body with a cap fitted, or it may have been removed when the hose was removed. I'd guess the cylinder is shot and need a rebuild or replacement.

Can you just replace your hydraulic limiter with a toplink?

Lot of mucking around disconnecting & refitting it if you want to lift 3pt, fix or replace the cylinder since he has one and get it back to OEM design. How do you go with yours, got it in a reasonable workable position with the fixed brace? No idea on how good the hydraulic system is, whether it's actually worth considering for yours, or if solid is better for his?

 

[shootem604]

I'm replicating the Woods Saf-T-Lok for my backhoe attachment as an interim measure - simple, effective, and cheap.

Currently designing a simple subframe design that will tie into the FEL subframe, so I'm not going to try to install a cylinder.

I've attached a pic of the brace/toplink system I saw on a Brands Mfg backhoe, mounted on a B7200.

 

[North Idaho Wolfman]

Have you installed the reinforcing bracket to the three point mount?

If you have not, your very likely going to do some damage trying to do what you think you want to do.

 

[dchimirev]

Have a read of post #3
http://www.tractorbynet.com/forums/attachments/260989-kubota-k-550-k-600-a.html

Yep, I've read that post about 20 times, great info. My question is, where exactly is this tee connection (I know it's a shot in the dark that someone has this exact setup and will know exactly the location of the tee).

Otherwise, if there is no tee, and I have to install one, which hose should I add it to? I'm guessing I should put in on the hose that carries the fluid form the pump to the backhoe controls. Or does the tee need to be only on the hose that would be used for digging? This way there is no fluid going to the limiter if i'm just swinging the back hoe or lifting it up?

 

[100 td]

The hydraulic hose attached to this port simply goes directly to a "tee" in the hydraulic source (pressure) hose that provides hydraulic fluid flow (powers) the backhoe.

He mustn't have read his own post, or he doesn't understand how a tee fits in a line. There could be a tee in the line or at the valve body with a cap fitted, or it may have been removed when the hose was removed

Yep, I've read that post about 20 times, great info. My question is, where exactly is this tee connection.......Otherwise, if there is no tee, and I have to install one, which hose should I add it to?

I'm not sure which part you don't have a handle on here? Have a look at the lines, valve body and connections, if you aren't sure what you are looking at, take some pics and post them here and someone will assist with identification of what you have pictured.

When teed into the main line any operation of the hoe will pressurize the cylinder to a varying extent. Whether this setup is better overall than a solid link, I don't know. As originally noted it would allow the raising of the 3 pt which may be advantageous in some instances. It may also act as a cushion and be a little less abrupt on the top link mount.

 

[dchimirev]

Yea, looks like all the answers were already there. I just didn't put all of it together. Thanks for the patience, and explanations. I'll dig around all the hoses and connections to see if I can find the tee, if not, i'll put one in on the supply line. Thanks again.

 

[100 td]

Pull the cylinder out and disassemble and see what costs you are up for, for a start, as a solid rod may be an easy fix if hose, fittings and cylinder need to be purchased and the dollars add up. I haven't looked at other 3pt hoes of this vintage, perhaps this hydraulic method was discontinued due to effectiveness, design or cost reasons, so if an expensive fix, you may go for a solid replacement instead.

 

[dchimirev]

So I took some time to look around at the hose and valve/controls layout, now that I have a better idea of what i'm looking for. So each "valve body" (sorry if that's the wrong term) has 4 ports for a hydraulic line to attach too. In each case only the very left and very right ports are utilized, with the middle two plugged with cap bolt. My question is, can i just unscrew one of these plugs and run the line to the limiter from there, or are those plugs should not be touched?

Some pictures of what i'm talking about.

 

[dchimirev]

Pull the cylinder out and disassemble and see what costs you are up for, for a start, as a solid rod may be an easy fix if hose, fittings and cylinder need to be purchased and the dollars add up. I haven't looked at other 3pt hoes of this vintage, perhaps this hydraulic method was discontinued due to effectiveness, design or cost reasons, so if an expensive fix, you may go for a solid replacement instead.

I took the cylinder to a shop and they said it's trash. I'll see if I can find something similar in size that would fit this application. Hopefully it won't cost an arm and a leg. But it's great to know I can always go the solid link route if it comes to it.

From what I understand one the solid limiter is in, I will not be able to raise or lower the 3pt hitch? So I'll have to pick a hight that's good for digging and travel?

 

[100 td]

A swivel tee fitted on the valve block in front of the main line will allow you to take off for a new cylinder, if you go that way. I expect the caps you are talking about are just caps on the end of the spools, (or they are a double of the same work ports for different access, but I doubt it), so no good anyway.

https://wbcindustrial.com/6602-8-8-8-male-jic-to-female-jic-swivel-run-tee-hydraulic-adapters

 

[shootem604]

With the Saf-T-Lok style, you can pull the 3/4" bolt or pin that connects the braces to the toplink, and then you can raise/lower.

 

[dchimirev]

Thanks for all the help so far, really use full info.

I'm not having any luck finding the right type of top link that swap into where the original cylinder would go. I'm guessing i'm just looking in the wrong places. Any links to good web pages would be awesome.

I was also thinking using my old non functional cylinder to made a home made contraption. I would drill a hole thru the piston and put a pin thru it to stop it from collapsing. I can have the pin in there while using the back hoe, then take the pin out in order to raise or lower the back hoe with the 3pt hitch. What's your thoughts on doing something like that. Thanks.

 

[shootem604]

Hmm, that's a thought. Should work I think.

 

[grosel]

I have an L650 three point backhoe which I would like to install hydraulic limiter cylinder on, Does anyone have any information on the cylinder itself like bore stroke total length ect.?

 

[Brofessor]

I reconfigured the single line pressurizing the three point limmiter-cylinder by tee-ing it into the right side outrigger cylinder. Now when I use the outrigger, it also pressurizes the three point limmiter-cylinder and takes most of the weight off of the rear tractor wheels. To lift the backhoe using the 3-point, now the right side outrigger valve must be positioned to the lift position and then simultaneously operate the three point lift lever. The backhoe system now works much better than the original design. Also, I found the most inexpensive fittings and hose thru "surpluscenter.com"