Well I got the backhoe out tonight to try and scrape some snow.... bad idea!!!! I did figure out the rear end is not locked and that is worn ag tires suck on concrete. Back the hydraulics. I still haven't checked the pressures but I am pretty sure that my back spool needs rebuilt. A lot of the back cylinders drift, even the ones that i was told were rebuilt. One of the our riggers will pick up the back end the and i can move the back end with the swing function. That kinda tells me that i am getting good pressure back to the spool but maybe not to the cylinders. As soon as these 16" of snow melts i am going to hook up the gauge and see what pressure i am getting to the cylinders. I will keep everyone posted.
FEL strong but Backhoe Weak... What would cause this? VIDEO
- Thread starter parluskq
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J_J
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Here is a PDF of the V20P.
http://www.phtruck.com/download/hvd/HVD-Service-Literature/Gresen-Spare-Parts/V20SpareParts.pdf
It looks like your valve has a no relief plug in the port normally used for a relief.
That means that the BH valve depends on the main relief valve for protection.
You could add one if you like.
You may have a combination of cyl and valve leakage so it might be difficult to get a good pressure reading.
Some parts of that valve can be rebuilt, but if the spools are worn, there is no fix for that kind of damage.
To check the pressure, I would install the hyd gauge in a tee in the IN port of the first valve.
Then you can see the pressure for any spool in that circuit.
http://www.phtruck.com/download/hvd/HVD-Service-Literature/Gresen-Spare-Parts/V20SpareParts.pdf
It looks like your valve has a no relief plug in the port normally used for a relief.
That means that the BH valve depends on the main relief valve for protection.
You could add one if you like.
You may have a combination of cyl and valve leakage so it might be difficult to get a good pressure reading.
Some parts of that valve can be rebuilt, but if the spools are worn, there is no fix for that kind of damage.
To check the pressure, I would install the hyd gauge in a tee in the IN port of the first valve.
Then you can see the pressure for any spool in that circuit.
Thanks for the link, I was looking at that pdf last night trying to figure out what all i need to be aware of. I found a little better pic in this pdhttp://www.a-lhydraulics.com/Files/V20%20Gresen%20Valve.pdf Here is the pic if my valve
J_J
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That picture is for the work ports section of the stacked valve.
Okay, a little update. I finally got a gauge to check my pressure but it ended up being broken. So i figured i would just go ahead and pull the pressure relief valve and found that the spring was (picture Below). I am sure this will lessen the valve pressure which will cause my backhoe not to be strong but my front end loader had plenty of strength and as far as i can tell there is only only one relief valve to the entire machine:anyone:. The valve spool is a Gresen 2712 what a M stamp . Where can i find a new spring? I have searched the net.
J_J
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I believe Parker owns Gresen now, so I would call Parker for a part.
I called parker and they were unable to help me without a part number,The only numbers on the valve body are 2712 on the top with the letter M, and 040379 on the bottom. I am not sure is this is a V70 or what. Do you happen to know? I took the broken gauge back today and should have a new one by thursday.
Shadow99
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Ok, here's a quick temp fix for that. Had to do same thing on my no longer available (Italian-made), 2 spool FEL relief valve spring. Grind the tail end of the spring flat, check it regularly with a square, on a flat surface. As close to 90 degrees as possible.
If you have some measuring calipers or micrometer, measure the busted off piece. Also measure the diameter of the spring.
I found a steel bushing at TSC, that was the right Outer Diameter & (close enough) on the Inner Diameter. Had to cut it almost in half, to get a piece just a bit longer than my length measurement (you can always make it smaller, but it's harder to stretch it, when you cut it too short). Back to your beltsander/grinder to square it up (start on the high-side, work to the low-spot).
I put my bushing in first, due to the design of my valve, its just a pocket in the valve-body & no oil flows thru there. Then I dropped the remnants of the original spring in & re-assembled the rest of the valve. Hasn't failed yet! Might be worth a try.
Shadow
If you have some measuring calipers or micrometer, measure the busted off piece. Also measure the diameter of the spring.
I found a steel bushing at TSC, that was the right Outer Diameter & (close enough) on the Inner Diameter. Had to cut it almost in half, to get a piece just a bit longer than my length measurement (you can always make it smaller, but it's harder to stretch it, when you cut it too short). Back to your beltsander/grinder to square it up (start on the high-side, work to the low-spot).
I put my bushing in first, due to the design of my valve, its just a pocket in the valve-body & no oil flows thru there. Then I dropped the remnants of the original spring in & re-assembled the rest of the valve. Hasn't failed yet! Might be worth a try.
Shadow
Jim Timber
Veteran Member
The shorter the spring is cut, the stiffer it will be. You might end up with a fickle relief setting (hard to dial in just right), but it shouldn't pose a problem as long as you can make it bypass at the right PSI. Good work around Shadow.