Replacing loader valve on a Freeman 4000 loader

[Bobs1953]

I have a Freeman 4000 loader. I had it checked out at a hydraulic shop and it's unrepairable. From what I've learned from the folks on this site Gresen built the valve for Freeman and later Bush Hog bought out Freeman. I couldn't find the valve on any Freeman literature but I found it on the N tractor site. They had a parts manual for it listed under Freeman 4000 parts list. It's a Bush Hog model 51085. Now in a perfect world I would order a replacement. I talked to the two most senior employees in the parts department at Bush Hog and parts have not been available for decades. So I just need to replace it. I've found several valves from Prince that would work with one caveat. The hydraulic fluid return port on the valve going to the reservoir was special for the Freeman/Bush Hog loader. It is an o-ring seal that sealed the bottom of the valve against the mounting plate on the loader. This plate had a pipe that connected to the loader reservoir. I can't find any manufacturer that has this type of return(outlet) on the valve. I can get a valve with a 3/4 NPTF on the outlet as well as other connections. The challenge is how to mate the outlet connector with the return that is on my loader and not wind up with something that looks like a Rube Goldberg. I'm sure many of you with a Freeman loader have already crossed this bridge and I would love to know how you did it. Pictures of your final product would be most helpful as well as the loader valve you used. I've included two pictures of my valve and mount for clarity. Notice the o-ring on the bottom of the valve. This is the outlet for the return and is not threaded. They simply milled a recess in the valve for a o-ring. Any assistance is greatly appreciated.

 

[BarnyardEngineering]

The return is not under pressure. Just cut the pipe off below the 90, slide the return hose over, and clamp it.

 

[wore out]

"B.Y.E." has probably the only option you've got, and no reason it won't work.

Out of curiosity, what is wrong with your old valve, is something wrong with the main casting? Or?

 

[Bobs1953]

The hydraulic shop replaced the seals for giggles and grins but when they measured the spools and bore the it was way out of specs. They tested it on the bench and the hydraulic fluid way blowing by the spool
in the chamber. They said they might could try to re-chrome to build back to original but thought replacement was best. Also not having the original specs was a problem for them.

 

[RobCons]

Barn Yard has it. I also suggest looking on the web page for Surplus Center. They have lots of valves including nice joystick style and all the fittings you will need. Just make sure to match the valve to your system. Open or closed.

This post was edited by RobCons on 04/18/2022 at 02:43 pm.

 

[Bobs1953]

Thanks. I am familiar with Surplus Center. Got my replacement gear pump for the same tractor/loader/backhoe as this post is referencing. I talked with them last week.

 

[Bobs1953]

Thank you. I will look into this.

 

[caterpillar guy]

I would do the same as Barnyard only I would probably use a big punch or rod to see if I could swage the end open just a wee bit. This would help with holding the hose and clamp on better. Clean up the end so no sharp edge on the end. There are also some better clamps than regular hose clamps that will tighten up with a socket or end wrench. There is no pressure there except the static pressure of the oil returning to the tank/reservoir.

 

[Determined]

(quoted from post at 14:34:54 04/18/22) The hydraulic shop replaced the seals for giggles and grins but when they measured the spools and bore the it was way out of specs. They tested it on the bench and the hydraulic fluid way blowing by the spool
in the chamber. They said they might could try to re-chrome to build back to original but thought replacement was best. Also not having the original specs was a problem for them.

When they tell you it is way out of specs then they tell you they don't know what the specs are it make one wonder.

What symptoms lead you to decide you need to replace the valve?

 

[Bobs1953]

The way many different people have explained it to me (including two different hydraulic shops) is that fluid control in the valve is maintained by a very precise fit between the bore of the valve and its
respective spool. It is metal to metal with very precise tolerances. The hydraulic shop mic'd the spool outside diameter and the bore inside diameter after disassembling the valve. If there has been enough
wear over the years (which was my case), then the bore diameter may be too large and begins to allow fluid to run by the spool instead to through the milled passages in the spool. You have loss of fluid
control. They actually tested my valve for this and confirmed that fluid was blowing by the spools. I've been told there are shops that can build the spool diameter back to once again achieve a nice and proper
tight fit between it and the bore but it's very expensive to do so, like many times the cost of a new valve. If you had an external leak on your valve it could simply have been an o-ring replacement at the end
cap. I didn't have an external leak. My leaks were all internal.

 

[Bobs1953]

Thanks, I appreciate your advice.

 

[stevieb49829]

As others have suggested, if you want to continue to use the plate as a mount, cut the pipe off wherever you can to attach a return hose, get a replacement valve assembly that you can screw in a barbed fitting (3/4 NPTF) on the return, and connect the two via a short chunk of 300 psi one wire rubber return hose. You could go as far as welding a 3/4 NPT coupler onto the pipe stub, so you can put a barb fitting on that end also, or weld the barb fitting directly to the stub. Then it's just some geometry to make the return hose fit. Where's your filter? steve

 

[Bobs1953]

The screen filter is up at the front of the tractor right before the fluid enters the pump and thanks for the advice.

 

[Determined]

(quoted from post at 11:57:39 04/19/22) The way many different people have explained it to me (including two different hydraulic shops) is that fluid control in the valve is maintained by a very precise fit between the bore of the valve and its
respective spool. It is metal to metal with very precise tolerances. The hydraulic shop mic'd the spool outside diameter and the bore inside diameter after disassembling the valve. If there has been enough
wear over the years (which was my case), then the bore diameter may be too large and begins to allow fluid to run by the spool instead to through the milled passages in the spool. You have loss of fluid
control. They actually tested my valve for this and confirmed that fluid was blowing by the spools. I've been told there are shops that can build the spool diameter back to once again achieve a nice and proper
tight fit between it and the bore but it's very expensive to do so, like many times the cost of a new valve. If you had an external leak on your valve it could simply have been an o-ring replacement at the end
cap. I didn't have an external leak. My leaks were all internal.

What I was trying to ask you was; what was happening that you yourself decided the valve is the cause of your problem?

I am assuming something was either leaking externally or not functioning properly.

The reason I ask the question is there are other parts of the hydraulic system that can cause problems that are sometimes blamed on the valve being bad.

-Bad gland seal in a cylinder can cause the loader to leak down
-Broken spring in relief valve can result in low pressure
-Worn out pump unable to provide sufficient flow or pressure
-Even mechanical binding can give similar symptoms as a hydraulic fault.

The above and many other conditions often lead people to making an incorrect diagnosis, personally I don't like spending money and time on new parts if they don't solve the problem.

 

[Bobs1953]

I agree with you completely. Not a fan of part swapping parts until something fixes it. So what happened that lead to my current situation you ask? Well I was moving some relatively loose soil for a neighbor
in their woods. I got hung on a root while lifting the bucket. I blew a hose on one of the work ports of the loader. I had already replaced three of the four previously as they were looking rough. At this
point I'm getting another hose thinking that replace the hose, add a little fluid if necessary and get back to work. After replacing the hose if I tried to lift the bucket it would barely move and the
hydraulics were screeching like when you max them out. I would let go of the valve and try it again. Same thing. The bucket curl control worked fine. It was only on the bucket lift. I managed to get the
bucket lifted enough to get the tractor home. I swapped the bucket lift with the bucket curl ports on the valve to see what would happen. The bucket lift worked fine but the bucket curl would hardly move and
screech. The backhoe worked fine as well. At this point I knew the cylinders were okay and the problem was in the valve. I took it to the hydraulic repair shop and they worked with it and told me that fluid
was blowing by the spool on the lift control and replacing the valve was their recommendation.

 

[Bobs1953]

Forgot to mention: no external leaks and no broken springs in the valve when inspected by Hydraulic shop. Fluid blowing by the spool on their test bench.

 

[Determined]

(quoted from post at 16:08:58 04/19/22) I agree with you completely. Not a fan of part swapping parts until something fixes it. So what happened that lead to my current situation you ask? Well I was moving some relatively loose soil for a neighbor
in their woods. I got hung on a root while lifting the bucket. I blew a hose on one of the work ports of the loader. I had already replaced three of the four previously as they were looking rough. At this
point I'm getting another hose thinking that replace the hose, add a little fluid if necessary and get back to work. After replacing the hose if I tried to lift the bucket it would barely move and the
hydraulics were screeching like when you max them out. I would let go of the valve and try it again. Same thing. The bucket curl control worked fine. It was only on the bucket lift. I managed to get the
bucket lifted enough to get the tractor home. I swapped the bucket lift with the bucket curl ports on the valve to see what would happen. The bucket lift worked fine but the bucket curl would hardly move and
screech. The backhoe worked fine as well. At this point I knew the cylinders were okay and the problem was in the valve. I took it to the hydraulic repair shop and they worked with it and told me that fluid
was blowing by the spool on the lift control and replacing the valve was their recommendation.

Thank you for providing further information, from what you posted here are are my opinions;

-What are the odds that the exact moment the hose blew the spool valve finally wore out to beyond it's useable life?

-Is it possible that some dirt or other material got into the system when the hose was replaced?