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Volvo help needed - setting pressure on optional hydraulics for thumb

Upta-Maine

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Jan 3, 2020
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Maine
Hope everyone had a good Fourth of July weekend.

I went to Volvo today and they sold me two adapters (but I'm thinking I only needed one). One was in stock and the other I pick up on Friday. They said it is much cheaper and easier to adapt the test fittings on my pump rather than replace them. They sold me a 11666027 but I think this adapter goes from the second adapter I am buying to their preferred gauge set. The second item (which I don't have yet) is a 11666023. I think this adapter converts from the 1.5 thread on the pump now to a 2.0 thread that my gauges already have on one end of their 60" lines. This second adapter should be the one I need and was not included in my gauge set. BTW - my gauges came in today and they look pretty decent.

FwF -

Related to setting the relief pressure in the aux circuit based on the pics we have already reviewed (location of correct relief valves) and referring to the attached image - from what I see in the shop manual to adjust the high pressure relief....I loosen the hydraulic line at the tip of the relief valve, then loosen lock nut #2, then turn screw #1 all the way tight, then loosen lock nut #4 then adjust screw #3 in or out 1/4 turn if I want to bump the pressure up or down by 1,365 psi. Once I have it set I lock the adjustment down by tightening lock nut #4.

A couple comments:

1) That seems like a really touchy adjustment (1,300 psi in a quarter turn). Maybe this is where you said things could get dangerous if you don't know what you are doing....? I will be very careful and just make tiny adjustments and then check my gauge each time.

2) Isn't there going to be fluid coming out of the line attached to the end of the relief valve if it is loose or only if I retract the thumb? You had mentioned to loosen it and then adjust the relief valve but the manual says to disconnect the line completely and plug it. Not sure if I would have the correct plug/cap to do that.

3) What do I do with the "low limit" screw? Should I be setting that to something after I have my "high limit" set? I have no intentions of ever running a hammer on this machine - not sure if that matters but I wanted to mention that.

Also - the BSPP fittings are proving to be a bit of a challenge. Volvo didn't have any in stock and suggested I go to a hydraulic store. I stopped at two today and neither have any female BSPP-10 fittings. I am trying a third (larger store) tomorrow.

Thanks,
Scott
 

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  • 2 stage pressure relief valve.JPG
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BigWrench55

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Blue circle is where you want to check your pressures on the left side of the arm. Red circle is where you should connect the thumb. Green circle is the shut off valve so that you can remove hoses and not have oil draining from the line. You will need to adapt your gauges to the blue circle. But from there you can't stop the oil from draining when you remove that fitting unless you find something to plug it. I would check the pressure before you make any adjustments. You may have the correct pressure already.
 

Willie B

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I'm dealing with port relief valves on a John Deere backhoe now. It isn't system pressure you need to address. Thumb moves to position with protected system pressure. Squeeze too hard against it with the bucket, it'll raise pressure above protected system pressure.
A hydraulic shop sold me a externally mounted valve to vent excess pressure to the other side of the piston. '
My John Deere backhoe has Port relief valves. They take hose pressure send it back to the filter.

Imagine a backhoe boom lifting on 3500 lbs pressure, then, valves close, you extent crowd & dipper fully loaded. Leverage against that cylinder would raise pressure above pumped system pressure, It vents at 4500 LBS.

The Case solution is a pressure relief in the actual piston.
 

funwithfuel

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Ok, you won't be on the low side at all, you'll be on the high side. Crank in the low side, bottom it out then back it off a hair. Then adjust the high side to 2500 psi as read on the pump discharge test fitting. You will need a helper to pull the function so you can make your adjustments. Remember shear mode uses high side of 2 stage port relief. Then adjust single stage on back side of valve for "open" function.
 

Upta-Maine

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Maine
OK - that makes sense.

I was getting confused with the idea that we are now going to try to measure pressure out on the stick - I was under the impression that we were sticking to the pump discharge test fittings. I'm assuming the suggestions about connecting my gauges to the BSPP fitting above the shut-off on the stick is just another way to perform the same test....? Setting the same relief valve just taking the pressure at a different location......which I would need even more fittings for since my gauge kit doesn't have anything even close to fitting that port.

Also - do I need to be concerned with the small tip-mounted relief valve hydraulic line leaking or it will be fine loosened? I'm making all of these adjustments with the engine/pump running....correct? I don't shut it down between tests.
 

Upta-Maine

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Meaning I don't shut it down, make the adjustment on the relief valve and then turn it back on and take the measurement.....or do I?
 

funwithfuel

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I never shut down in between, it is recommended that you do. There will be dribble at the loose fitting, but not a gusher. We're only looking at 450 psi. If it's a concern, place a rag around it. You are only loosening the fitting enough to allow the relief to turn without twisting the line.
If you were running a motorized implement on the stick, or something with significant flow, we'd be checking at the stick for sure, but we'd also be using a flow meter, we're not, so we won't.
Tiny increments make decent changes.
I almost forgot. Draw a line down your relief with a paint pen. When you are done with the high side, go and put the low side where it was. Doesn't have to be perfect, just close. That way the low side is available to you in the future should you need it.
 

Upta-Maine

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Thanks FwF. A couple more questions I thought of today:

1) The manual says that the P1 (PL) pump is nearer the engine and supports the slew motor, arm cylinder, left track motor and the OPTION DIGGING UNIT. My guess is this is the port that I want my gauge on to check the pressure when I operate the thumb with the shut-off valve on the stick turned to off (deadheaded). P2 (PR) pump is further away from the motor (closer to the access door) and it supports the boom cylinder, bucket cylinder and right track motor - I should not be doing anything with this test port related to the thumb circuit. Does this sound right?

2) What engine speed (RPM) should I set the machine at when testing/adjusting the thumb relief valve (if adjustment is needed)?

3) With the engine running but none of the hydraulic controls being active - what will my gauge read that is connected to the test port of P1?

4) Assuming the thumb relief valve is already set to some reasonable pressure - how long can I apply the thumb pedal without doing damage (as the circuit will be deadheaded)? Meaning am I only supposed to activate it for less than a second or can I hold it for a couple seconds to get a good reading on the gauge? Is this something to be nervous about?

5) My gauges are 4,000, 6,000 & 10,000 psi. I would think that I should start with the largest and then make sure the pressure is within the 4,000 psi range before putting that gauge on to get the best granularity on the exact pressure for the final setting....? Or do the gauges have protection against over-pressurization?

6) While I have the gauges out - should I be checking the pressure of any other hydraulic circuit to establish some confidence in the health of my machine?


Thanks,
Scott
 

Ben Witter

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I would suggest just checking the pressures before trying to make any adjustments. You stated this had a tilting bucket before so the reliefs may have been set down from OEM settings. If they are already set at 2500psi there is no need to make any adjustments. If you go messing around first then you will have to correct what you have changed.
 

Upta-Maine

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Agreed Ben. I'm really hoping the pressures are where they need to be so my weekend gets a lot easier. I can just get to work and see if all the time and money pays off with this machine. But.....with my luck the pressure is off a bit and I'll have to adjust it. Either way I want to make sure I understand it so when I get up north I can finally run the excavator without worrying I'll bend a rod. It's been a long time that I have been working on this machine - better part of 9 months (a bunch of small things). I am going to finally enjoy operating it rather than laying underneath it. :):D:):D
 

funwithfuel

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Rule of thumb, with a Volvo. As you sit in the machine, left pedal and lever run by left pump. Right pedal and lever supplied by right. So yeah, you wanna be on pump 1.
Always set pressure at full throttle.
Running with no request for work will yield standby pressure, I don't have the spec in front of me but it will be a low value 2-300 psi iirc.
The relief is there to prevent harm from occurring. You dont want to sit there for 2 minutes, but 15-20 seconds at a time is fine. Any more and you're just generating a lot of heat. I would start w/ the 6k gauge. I will find a spec sheet for you,
 

Upta-Maine

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Hey Guys -

Great news - things went very well with measuring and adjusting the hydraulic pressure on my aux (thumb) circuit. Here is how it went:

I put my gauge on the test port of P1 and started the machine. The pressure at idle is around 500psi. It climbs to around 600psi at full throttle. After dead-heading the valves on the stick I stepped on the thumb retract pedal and the gauge went to 2900psi. I stepped on the thumb extend pedal and the gauge went to 3900psi. I have no idea why Volvo (or anyone else) would have those pressures set to run a grading bucket that has the same size pistons on either side of it.

So I worked the front (2 stage) relief valve first exactly as FwF indicated and hit it on the first try. After tightening everything back down my thumb extend pressure now sits between 2400 & 2500psi. For whatever reason the needle shakes a bit when the aux relief valve is engaged but it's no biggie - it only fluctuates on the needle less than 100psi. I went after the rear valve next which was a little tougher as I had to loosen some hydraulic lines to move them out of the way to get to the rear adjustment which I learned was an allen wrench. This time it took me a couple attempts but finally go the pressure to be identical as the front valve. Again the needle fluctuated but only by 100psi. I tested the thumb and it works great.

I want to thank you guys a bunch for the help. It really was a good feeling to not only know that the thumb is working the way it should but to know how and why it is working that way. $79 in a gauge kit, $40 in hydraulic test port adapters and priceless knowledge shared by you guys.....and now I'm in good shape.

Thanks again,

Scott
 
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I’ve been trying to go the same thing on my Volvo 240b but I seem to be having issues. I got the right side of the stick hood to go but when I got to the left it won’t go over 1000 psi and will not hold pressure as soon as I let off the button. Does anyone have any advice? I’ve tried adjusting the valve in every position and way possible
 

funwithfuel

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Welcome Travis. Im assuming you have gauges. Back to basics. Have you checked your pressure with the circuit deadheaded against closed valves? Let's start there. And , lets have you swing by new member introductions and get a fresh thread started. You'll get more eyes looking at a new thread vs a dug up zombie thread.
 

volgano

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Jul 22, 2021
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Please, can someone tell me what type of oil is needed in the swing gearbox for the Volvo EC160 BLC
THANKS
 
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