Hydraulic pressure adjustment

[Bonaro]

Are you sure that is not the price for the complete valve section (still high) or even for the loader valve assembly in its entirety?

Hard to imagine that would be the price for one piece of one of the valve sections. But what do I know?

Not sure, Some on here insist you cant buy the spool separate but I find it listed separate in the parts break down. I know I'm not spending $850 on this tractor. I have seen the control valve assembly listed for as much as $3200

 

[whitetiger]

Not sure, Some on here insist you cant buy the spool separate but I find it listed separate in the parts break down. I know I'm not spending $850 on this tractor. I have seen the control valve assembly listed for as much as $3200

You can not get the spools separate from the valve itself as the spools are select fit during assembly as you have been told.
If you would look at the part numbers, as shown in the pdf I have included, the spools and the complete valve have the same part number.

 

[Henro]

Not sure, Some on here insist you cant buy the spool separate but I find it listed separate in the parts break down. I know I'm not spending $850 on this tractor. I have seen the control valve assembly listed for as much as $3200

Well, Whitetiger explained why the $850 would would buy more than just the spool.

Since you do not want to spend that money, perhaps you can replace the assembly with an aftermarket unit. Maybe you can find something cheaper at surpluscenter.com, or elsewhere.

 

[Bonaro]

You can not get the spools separate from the valve itself as the spools are select fit during assembly as you have been told.
If you would look at the part numbers, as shown in the pdf I have included, the spools and the complete valve have the same part number.

OK...you are right... feel better now?
again...i'm not buying a $850 part no matter how it's sold.
I fixed the old valve assembly, all is good now

 

[07wingnut]

The o-ring kit I ordered for almost $20 arrived after 18 days and it had the wrong o-rings.
I drove down to Industrial Hydraulics and bout the correct size for $2.36.
I got it all back together, not more leaks at all. Polishing the spools fixed the leak and it seems to work smoother now.
It still wont lift the front end off the ground but I can roll the bucket and lift it. After I build a pressure valve to see what the pump is doing I may try to adjust the relief valve but until next winter I got tractor stuff to do

I do not think polishing the spool is what stopped the leak. All spools leak to a certain extent as oil leaks between the spool and valve body, the rate determined by the clearance between the two. The leakage is collected internally in the spool valve and rerouted usually to the sump. All the seals do is prevent this leakage from exiting the spool valve via the spool ends.

 

[Bonaro]

I do not think polishing the spool is what stopped the leak. All spools leak to a certain extent as oil leaks between the spool and valve body, the rate determined by the clearance between the two. The leakage is collected internally in the spool valve and rerouted usually to the sump. All the seals do is prevent this leakage from exiting the spool valve via the spool ends.

Right, excessive clearance between the spool and body would only cause the fluid to bypass between the up and down circuit and the bucket would settle. Mine had external leaks, oozing past the spools.
I polished the spools with steel wool, new o-rings, good to go

 

[Henro]

Right, excessive clearance between the spool and body would only cause the fluid to bypass between the up and down circuit and the bucket would settle. Mine had external leaks, oozing past the spools.
I polished the spools with steel wool, new o-rings, good to go

So in the end, polishing the spools really had nothing to do with the repair, as all that could have done was increase the clearance and therefore the leakage.

So the solution was new O rings. Glad you got it fixed.

By the way, your reply to Whitetiger was not very nice...he is very knowledgeable and was just trying to help you.

 

[lugbolt]

let's say a cylinder has a bore of 2", and the ram rod is 1" in diameter.

If it is a double acting cylinder (power in and power out), you will have a port at either end of the piston, which let's say in this discussion is in the middle.

There is a rod end of the cylinder and the other end

If fluid is applied to "the other end", oil will then be fed at pressure. Lets say, 2000 psi to keep it simple. The amount of force applied to the piston is roughly 6200lbs of force.

On the rod end, you have the area of the piston MINUS the area of the rod. That rod is in the way so you lose 1" of the piston, to keep it simple. So if the same 2000 psi is applied to the rod end, your force is somewhere around 4700 lbs. That's a ~1500 lb difference in force between lifting and downforce since loaders almost all have the rod end facing rearward.

Hydraulic Force vs. Pressure and Cylinder Size

Calculate hydraulic cylinder force.

www.engineeringtoolbox.com

hence, one should never ever judge a loader's lifting perfornance by whether or not it will lift the tractor's wheels off of the ground

I saw this often when I was at the dealer, guys would get a brand new L series, take it home (or take delivery) and 2 hours later griping because it wouldn't lift the front end off the ground. Several reasons, one, on hst's it's gotta be in neutral as the rear wheels need to roll slighly and with hst's they don't roll easily, and two the brake has to be off for the same reason. Can't tell you how many times I would have to go to a customer's house/land/farm and (1) take my foot off the brake (2) release parking brake or take it out of park and put range gear in neutral (3) explain to them that there is much less down force than there is lifting force because of the bias effect. Intentions were NOT to make them feel stupid, but to educate them, professionally. For a little while I had a copy of the link above to explain it but I gave that up too because people don't understand how to read and comprehend anymore. "Well my old Ford would lift the wheels right up"....yep...sure would, if it were that great why did you buy a new one? Secondly the geometry of the lifting mechanism was completely different. Thirdly the front end of the tractor was usually lighter weight in comparison (2wd normally) and fourthly, the wheels need to roll....and your new tractor is hst and not straight shift, hst does not have a clean neutral and pushing the clutch doesn't do anything but make it stop pulling, it still won't roll until you put the range shift into neutral or in some cases between ranges. Again, many refuse to understand, or just can't. Makes me glad I don't do that job anymore.

 

[Bonaro]

So in the end, polishing the spools really had nothing to do with the repair, as all that could have done was increase the clearance and therefore the leakage.

So the solution was new O rings. Glad you got it fixed.

By the way, your reply to Whitetiger was not very nice...he is very knowledgeable and was just trying to help you.

The spools were dull with some mild scoring and a few small pits. Polishing took out the dullness and helped with the scoring and maybe a little with the pitting. I am certain this helped the orings seal and certain will extend their life but Yes, new orings were certainly the major part of the fix.

No offense intended to Whitetiger. He and others were telling me how I couldn't buy certain parts one way or another and I had already said I didnt intend to spend that kind of $ on this. Apologies -> whitetiger

 

[Bonaro]

let's say a cylinder has a bore of 2", and the ram rod is 1" in diameter.

If it is a double acting cylinder (power in and power out), you will have a port at either end of the piston, which let's say in this discussion is in the middle.

There is a rod end of the cylinder and the other end

If fluid is applied to "the other end", oil will then be fed at pressure. Lets say, 2000 psi to keep it simple. The amount of force applied to the piston is roughly 6200lbs of force.

On the rod end, you have the area of the piston MINUS the area of the rod. That rod is in the way so you lose 1" of the piston, to keep it simple. So if the same 2000 psi is applied to the rod end, your force is somewhere around 4700 lbs. That's a ~1500 lb difference in force between lifting and downforce since loaders almost all have the rod end facing rearward.

Hydraulic Force vs. Pressure and Cylinder Size

Calculate hydraulic cylinder force.

www.engineeringtoolbox.com

hence, one should never ever judge a loader's lifting perfornance by whether or not it will lift the tractor's wheels off of the ground

I saw this often when I was at the dealer, guys would get a brand new L series, take it home (or take delivery) and 2 hours later griping because it wouldn't lift the front end off the ground. Several reasons, one, on hst's it's gotta be in neutral as the rear wheels need to roll slighly and with hst's they don't roll easily, and two the brake has to be off for the same reason. Can't tell you how many times I would have to go to a customer's house/land/farm and (1) take my foot off the brake (2) release parking brake or take it out of park and put range gear in neutral (3) explain to them that there is much less down force than there is lifting force because of the bias effect. Intentions were NOT to make them feel stupid, but to educate them, professionally. For a little while I had a copy of the link above to explain it but I gave that up too because people don't understand how to read and comprehend anymore. "Well my old Ford would lift the wheels right up"....yep...sure would, if it were that great why did you buy a new one? Secondly the geometry of the lifting mechanism was completely different. Thirdly the front end of the tractor was usually lighter weight in comparison (2wd normally) and fourthly, the wheels need to roll....and your new tractor is hst and not straight shift, hst does not have a clean neutral and pushing the clutch doesn't do anything but make it stop pulling, it still won't roll until you put the range shift into neutral or in some cases between ranges. Again, many refuse to understand, or just can't. Makes me glad I don't do that job anymore.

I understand what your sayin. I am new to tractors but I have seen many that could lift the front end. It woudl also help when digging out roots etc.
I got it working pretty good now. No leaks at all and I can lift the FE with a bucket roll. Right now I am waiting for the snow to stop so I can start clearing the driveway. Got a solid 6" with another foot on the way