U302 3 pt lift update

Based upon responses to my last post, and checking the service manual I replaced the hydro hoses that were leaking. I couldn't try to lift the plow again because its 3 miles away, and it was in the low 20's in Ohio today (didn't feel like freezing on the first day of the new year)! So I hooked up to my Bush Hog 6' finish mower and lifted it with no problem. I then added 6 suitcase weights to the rear of the mower (figure it would be close to 1000 pounds). It only lifted it 3/4 of the way up. I consulted with JoePro, and decided to increase the spring tension on the relief valve. I checked the pressure before as best I could. It was hard to understand the service manual instructions on how to move the levers to see what my pressure is (looked to be 170 psi). I found the proper yoga position needed to adjust the spring tension, and added tension. The 3 pt then raised the mower with weight completely. I gauged it again and found the pressure to still be 170ish.

Any thoughts/ advice if increasing the spring tension on the relief valve would raise pressure? Or how to accurately gauge the pressure? Or was my problem just the leaking hoses, and not enough spring tension?

BTW...adding 600 pounds to the rear of the mower is not recommended! There was a lot of flex on the mower lift points...but at least it worked for what I needed.

Wanted to show the weights piled on, and finally the arms fully up with the weight on.

good looking UB

I think you may be in the wrong port (2 or 3 instead of 1). If you didn't take the draft control decal plate off, it would probably still be covered?? The pressure you mentioned would be normal for those ports.

I had the gauge in the #1 port. The manual said to put the gauge in that port, and hold one of the levers back long enough to get a reading. I tried that and could not get a consistent reading. I tried raising the 3pt and got the 170psi reading while it was raising. If the pressure relief kicked in the gauge would peg at the highest setting. This is my first time working with a hydro system. Any help is appreciated. I just don't want to damage the pump, but would like to be able to have it working correctly to lift the new/old plow.

Got ya. It was worth a guess. What is the maximum pressure on your gauge? Sometimes the relief valve will cause the gauge reading to "jump" making it difficult to get a clear reading too. Especially if you are nearing the maximum pressure reading of your gauge.

You may need to wait till warmer weather to set your pressure. Cold oil can give you a high reading. Pretty awesome that your pump is still able to develop higher pressures.

Also... Are you easing the lever back. A sharp jerk to full open position will also make the gauge hard to read.

I am trying to figure out if the relief valve was my lift problem. Could it have either been out of adjustment, or the spring gotten a little weak, which cause the relief valve to kick in before it normally would have? In my uneducated mind that would make sense after making a minor adjustment to add tension solved my lift issue (I think). I did think about the fluid being thick due to the cold. I tried to warm it up, but this time of year it"s a little tough (-3 this morning). Thanks for your help.