Grading Box under joystick

[horticattleman]

I have a 425 and the box under the joystick is leaking oil BAD Should I just change the whole thing or can it be rebuilt and wherte do I get it? Thanks guys

 

[toy]

Make sure that you don't just have a loose hose first, I don't know how old your machine is but that is what I would try first. Be careful and wear eye protection but it may be just as simple as a loose hose or a loose fitting going into the valve. I have never had to do any repairs on mine in that area but some times the fittings have o rings where they screw into the valve chest or block, one of them may have a bad place in it. There are also fittings that are 45 or 90 degrees and they have a nut on them so that you can be able to adjust the direction that the hose leaves the block for routing purposes. It might be that you just need to tighten a hose or a fitting. If it was me I would pull the spark plug wires so the engine wouldn't start and I would position myself so I could see the block and I would have someone crank the starter on and back off and watch for seepage coming from the block. If there was something in particular that you were doing that made the leak worse I would have that portion of the joy stick used just thought I would mention that just in case that fit the situation. Before you do any thing though try to clean up where the oil has already leaked that is an important step, and I would like to add that any thing you do in life can be dangerous including working on hydraulics so be careful and work at your own risk.

 

[horticattleman]

Thanks toy I will start there

 

[ponytug]

I find that cleaning the leaking item first helps locate the actual leak. The valve bank (your box) is not that hard to dissassemble, but I always remember Terry's admonition to treat it like open heart surgery, clean, clean, clean.

Good luck! Until you rule it out, I would suspect a loose hose, or a cracked fitting. One of my hoses had the fitting crack inside the nut, and that leaked rather badly.

All the best,

Peter

 

[J_J]

horticattleman,

Maybe you have fixed by now, but if not, do what the other guys told you. It could be a leaking spool, cracked fitting, pin hole in hose, maybe things just need tighten up a bit. If the valve is leaking, you can try and tear it down and replace whatever that can be replaced, or take it to a hydraulic shop and let them test it first and rebuild, but first get an estimate. If a spool is leaking that does not use o-rings, there is not much you can do, because the spools are matched up fairly close to the bores. If the spool has o-rings, then replacement just might fix things like new. Hoses can be replaced fairly easy, and new fittings can be installed. If you are mechanically inclined, then you can so most of the work yourself. If you have to replace total valve, check out PT's price, and then look elsewhere if to much.

 

[Rivco]

The last time I got a price from keith at Power-Trac for the Sauer Danfoss Model 1637 3-spool valve ...the cost was over $500.00 !! . I ended up buying it through a local supplier for just over $300.00. That model spool valve does have O-rings and they are easy to work on...but like others have already said ....before you work on it ( open it up )...clean, clean, clean

 

[Carpenter]

I had a bad leak from the bottom valve body on my 425 and it turned out to be a loose allen screw on the bottom of the valve. I have no idea of it's purpose but tightening it stopped the leak.

 

[toy]

Thanks toy I will start there

you are welcome, if you wind up having to take more than one hose off to get to the problem it is always a good idea to label the hoses where they go and kind of describe it's location because sometimes memory will fail you trust on that I know. When you label them put the label in a sandwich bag or something like that and wire it to the hose that way oil won't get on your label and dirt and make it impossible to read and then you have to do a guessing game. There are other ways of doing this but this is just one suggestion. I have seen hoses labeled with masking tape and either the tape would come off or you wouldn't be able to read it when you went to reassemble the job. Good luck on your repair, hope your cost of repair is at a minimum but the feeling of satisfaction of making your own repair is over the roof.

 

[horticattleman]

I am wondering if me losing hydraulic pressure on the front arms is because of this. If I have more than 50 lbs on the arms, like a bucket, it falls rather fast, like from maximum hieght to the floor in a couple of minutes. WAY more than when I first got it.

I have not had a chance to work on it yet but hopefully will have a spare moment soon.

Thanks guys.

 

[toy]

I am wondering if me losing hydraulic pressure on the front arms is because of this. If I have more than 50 lbs on the arms, like a bucket, it falls rather fast, like from maximum hieght to the floor in a couple of minutes. WAY more than when I first got it.

I have not had a chance to work on it yet but hopefully will have a spare moment soon.

Thanks guys.

I am thinking that what you are talking about it a falling in 2 minutes you are referring to raising up the loader arms with the bucket on it and then cutting the motor off and it takes 2 minutes for it to fall to the ground or leak off to the ground, I believe all pts leak off but I haven't timed the rate that it takes it to fall all the way down on mine but it might not be a bad idea to do that and record it in your pt book or start a pt log book and write it down for future reference. You said that you had a oil leak on that block if it is falling faster than it used to that might be a clue to finding the problem. Find the hoses on the bottom of the loader loader arms and trace them back to the block since if you had a leak there then it would explain the fast dropping of the loader arms and naturally be the source of all the leaking oil. There is another reason for the arms to drop faster though that would have nothing to do with the oil leak that is coming from the block and that would be that the valve bank was itself bypassing more than it did when you first got the machine, it could be like one of the other posters mentioned a o'ring leaking in the valve block. If the block mounting bolts don't seem tightened down enough when you are working on it don't think that they necessarily need torqued down because to do so might stress the block and distort it enough to cause you to have trouble with the valve spools moving as they should and that could compound your problems. That is something though that you would have to use your own judgment on since you are the one that is there looking at it. Always remember to work safely as you work at your own risk. I hope your repairs are an easy fix and don't cost you much.

 

[toy]

If you haven't checked it out yet Carpenter mentioned that he had a similar problem, it might be a good idea to check that out. When one of us has a problem and someone else has had a similar problem it is good that we can communicate it to one another, thanks Carpenter for sharing that someday it might help me.

 

[toolz_not_toyz]

I've had the same problem for about a year now. It's gotten bad enough that I decided to take some action.

My aux valve is leaking from the bottom. This started happening after extensive use of the mini-hoe. With the engine off you can hear a "squishy" sound coming from the bottom of the valve. Figuring that the leak was originating at the bottom valve cover, I simply used a flashlight and a small mechanic's mirror to take a closer look. This revealed the "squishy' sound coming from between the valve cover and valve body at the back of the valve pack.

Unfortunately, I can't tighten the valve cover screws down any further without stripping the heads (mine are all Phillips screw heads, not Allen screw heads, which would be way better).

Now, I kinda figured there would be a seal of some sort between the valve cover and valve body...but there isn't. So I guess the only seal would be an O-Ring further up beyond the spring. But then I've got to wonder: is there supposed to be any oil in the bottom part of the valve? I don't mean oil came spilling out or anything when I removed the cover, but there is a bit of oil in the bottom.

I suppose to further disassemble all you have to do is pop off the cotter pin at the top and the stem will slide out of the bottom...is this right? I further suppose that there would be at least two O-Rings: one at the top and one at the bottom. Anyone know what size is required. Also, in my research I came across similar questions that made it clear you wanted to get a specific type of O-Ring that had the correct formulation for hydraulic oil. I assume the stuff from the plumbing aisle at the local hardware store would just be plain wrong.

Any direction would be appreciated. I'm amazed that there hasn't been much mention of valve maintenance in this forum over its history. Isn't this just something that will happen from time to time as the hours add up? Of course, I'm only at 122hrs now, so I supposed my PT 425 is jinxed.

 

[toy]

Did you get it fixed, if so what was the problem?

 

[J_J]

toolz_not_toyz,

On the valve thing, a lot of valves do not have o-rings. If your valve has o-rings, you can replace them. Yes, there is a bunch of o-rings out there. You can take your chance and replace with something similar, but if PT has them, I would get the ones that they were made for the valve in question. I you do not have o-rings, and the valve is leaking, it just depends on how much you can tolerate before fixing. Metal to metal wear is just that, once it wears , there is no fixing. Some might say, find a new shaft, but that would be difficult as they are made to almost match. If the body of the valve is worn, then what. You have to replace. Is it a solid body valve with three stems? If it is sectional, you can separate the sections, and replace just the one that is leaking, and at the same time, I would try and find some hex bolts to put things back together. The valve cover you refer to is just a cover to cover things like the float function, and that part is not pressurized. Your other option is to take the valve to a hydraulic shop and let them test and repair, since they would know about the correct o-ring, etc. Be sure and ask them if they guarantee their work? Good luck

 

[toolz_not_toyz]

Thanks J.J.,

I think someone had posted before that on the PT 425 the valve box is a Sauer Danfoss 1637. Aha! here it is:

http://www.tractorbynet.com/forums/power-trac/147421-box-under-joystick.html#post1701658

I can't seem to find an assembly diagram for it. It is a solid body though, from as far as I can tell at least. One of those previous posts mentions O-Rings so hopefully I can just slide the stem out if I remove the cotter pin at the top.

 

[Rivco]

Thanks J.J.,

I think someone had posted before that on the PT 425 the valve box is a Sauer Danfoss 1637. Aha! here it is:

http://www.tractorbynet.com/forums/power-trac/147421-box-under-joystick.html#post1701658

I can't seem to find an assembly diagram for it. It is a solid body though, from as far as I can tell at least. One of those previous posts mentions O-Rings so hopefully I can just slide the stem out if I remove the cotter pin at the top.[/QUOTE}

CORRECTION....I had a spelling Typo in my other reply...it should have read ...that model spool valve doesn't have O-rings. Sorry for any confusion.

 

[J_J]

Well now, if that valve is one piece of steel bored out and fitted with custom spools, then if it is leaking, you have some wear in that spool section, and there is really nothing you can do. It is just a matter of how much leaking you can tolerate. There are much better valves out there, much cheaper than the PT valves, that have o-rings, and are re-build-able. While you are at it, you could upgrade to a four spool valve, for that extra function you might add later. Two of these two spool joystick valves will cost around $325.


Directional Control Valves 220-905 Detailed Information

https://www.surpluscenter.com/item.asp?UID=2009071308263789&item=9-7677&catname=hydraulic

 

[Rivco]

Here are a few pictures of the 1627-2 spool valve that was originally on the 2004 PT-180 I owned. When I built my Mini hoe I installed a 1637-3 spool valve. The only difference between the 1627 & 1637 valve's is 1 extra spool. The 2004/2005 422, 425 2425 PT's and the Red PT's all had the Sauer-Danfoss 1637 valve. (as verified by Terry at Power-Trac)
What brand valve Power-Trac used prior to and after 04/05 is anybody's guess.

Picture 1 is as viewed from the drivers seat.
Picture 2 is the back or plumbing side.
Picture 3 shows the spool valve ( no O-Rings ).
Picture 4 shows the one peice cast machined valve body with no O-Rings.

 

[woodlandfarms]

So, anyone think there is a 4 spool version of this that could plug into the 3 spool version I have? Or something similar. Still wanting to make a 4th control for the grapple, bit with the way it is installed on the PT not sure of the outcome, may just stick with the idea of putting one on the other side, but I would love to chuck the SD as it has some serious leakdown issues...

Oh, here is the manual from SD for our version

 

[Bob999]

So, anyone think there is a 4 spool version of this that could plug into the 3 spool version I have? Or something similar. Still wanting to make a 4th control for the grapple, bit with the way it is installed on the PT not sure of the outcome, may just stick with the idea of putting one on the other side, but I would love to chuck the SD as it has some serious leakdown issues...

Oh, here is the manual from SD for our version

The literature says there is a power beyond port on the valve that is plugged. That seems to suggest that you can connect that port to another valve of however many spools you need.
Hydraulic valve power beyond or high pressure carry over