3 pt. Hydraulics

Anderson · Aug 18, 2000

I've been monitoring this message board for quite a while, and could use some help.

I purchased an L3600 last month, and have been getting used to some basic operations. I purchased a 7' back blade, and am a bit frustrated by the number of times I have to climb off of the seat of my little beauty to adjust the top link for more or less cutting, and the non fixed lower link for the angle. So I've decided I need to upgrade those two with hydraulics.

I have two factory installed hydraulic circuits for the rear of my tractor that arent used for anything (the loader uses a remote mounted joystick). I have reviewed many threads about hydraulic top links, and am getting confused.

How should I plumb the system?

W5FL · Aug 18, 2000

The two factory installed circuits (4 valves) should have two actuating handles already installed on the valves. There should be no plumbing. Just hook up the hydraulic links.

I bought my top hydraulic link from my dealer. He ordered it from Gannon and they custom make it with the correct ends for your tractor. All that is left is for you or the dealer to install the ends on it for the quick connect. Each hydraulic factory installed circuit takes TWO valves for each hydraulic link. One is input and one is output. I only had one circuit (2 valves) and one actuating lever so I just installed the top link. It is the main one. Many people use the bucket dump circuit valves from the loader to get two more valves (1 circuit) for a tilt hydraulic link.

TomG · Aug 19, 2000

If I understand, you've got a 4 lines ending in quick-disconnects on a bracket mounted a rear fender. The 4 lines go to a spooling valve with 2 sections, and a pair of lines goes to each section. I think of a pair of lines off a spooling section as a circuit.

If that's the set up, then one double acting hydraulic cylinder can be hooked up across each pair for your upgrade. Nothing has to be done other than getting cylinders with the right travel and ends, and hoses that end in male quick-disconnects.

In the standard open centre systems I know, it doesn't make any difference which way a pair is connected to a double acting cylinder. Reversing a pair just reverses the cylinder motion.

In an open centred system, with all spooling valves centred, any pressure just flows through the valve to the return. Pushing a valve lever one way feeds pressure to one line (and one side of the cylinder). The other line acts as a return for oil on the other side of the cylinder. Pulling the valve the other way just reverses the pressure and return lines. The correct hookup is which ever way works best for you. I connect my top link so that pulling the valve lever back tilts the box scrapper back, but that's just personal preference.

On the other hand the hook up does make a difference if running an implement like a backhoe off a spooling valve circuit. Most, or all, hoes have a line marked 'INPUT,' OR 'P.' The input has to be connected to a pressure line or major damage will happen. If you're unsure which line gets pressure when a valve is pulled one way, grab a hose and pull the lever. You'll feel the hose that gets pressure stiffen.

Anderson · Aug 21, 2000

Thanks for the help. I took off my front end loader this weekend, and spent some time looking at the setup, and am starting to understand how it all works.

When I take off my FEL why do I have to turn the screw on the remote valve cluster 1/4 turn.?

TomG · Aug 24, 2000

I'm afraid I don't have an answer. A lot of this stuff is terminology. The way I understand the terms is that an external pressure line coming off a tractor hydraulic pump is a remote. A common use for remotes is to power a set of spooling valves. The remote goes to the spooling valve input, and the output goes to a return line. My spooling valves are fitted with quick disconnects. I'm not aware of screws on the valves other than those to hold on plates etc.

I'm not sure if the problem was that the hydraulic lines wouldn't come apart or some other reason why the loader wouldn't come off. When connecting or disconnecting hydraulic lines, its a good idea to relieve line pressures by setting implements on the ground and then operating the spooling valve levers both ways. I haven't had problems getting lines apart, but I think I've heard of people having trouble unless pressure is relieved. However, I've had problems getting lines back together unless I relieved line pressure.

Anderson · Aug 24, 2000

Thank you, thank you, thank you I really needed the terminology lesson so that you guys (and myself) will know what I'm talking about.

I have no problems with it, I'd just like to know what I'm doing.

It's a 1/4 turn screw recessed into the front of the remote spooling valves for the FEL. The direstions say to turn it 1/4 turn when the loader is removed

It's some kind of bypass or on/off because when I re attached my FEL I forgot to turn the screw back, and I couldn't get anything to move on the loader.

W5FL · Aug 24, 2000

Never was real sure what you had. Do you have one lever to control the rear set of valves(2 on rear) or 2 levers and two sets of valves (4 on rear)?

If you only have one set (that is what mine came with) the cost of adding a second set is about $750. That is why some people use the dump valve connections (2 valves and horizontal motion stick on loader) as a second set of valves.

Anderson · Aug 24, 2000

I have two levers mounted next to the 3pt position control, and two sets of valves (4 quick connects)mounted on the back.

I've concluded that the job at hand is fairly simple. I'm planning on measuring the min/max length of the upper link, and lower adjustable arm, and try to purchase cylinders with the appropriate travel.

Any advice on cylinder diameters?

W5FL · Aug 24, 2000

I can measure mine if you want exact dimensions, but it is approximately 4 inches in diameter. I suspect it would lift the tractor. It is kinda important that it go as short, but not much shorter and as long, but not much longer than the stock adjustment link. That keeps you from breaking something or bending something that you did not mean to do.

As I stated, mine were ordered from Gannon and took about a week to get here. The dealer put the ends on the hydraulic hoses and that was all there was to it, except to plug it in. Really a good investment.