Turning Hydraulic relief pressure up on ford 3500?

Jhutch · Apr 18, 2020

I have a ford 3500 loader with backhoe on it, is there a way to
turn up what pressure the relief valve opens? Tractor has a
new pump that?s ran off crank. feed goes to the hoe first then.
from the hoe controls it returns to the loader control valves
. witch feed it, then back into the tank. I believe the relief valve
is opening to easy. If the front tires sink in the ground some
the back hoe can not push the tractor back while digging it
does even put any strain on engine trying, to push it with hoe
like other hoes I have used when trying to ask more then they
could do. it also won?t lift the front tires with loader most of the
time. The loader controls leak when using it but lifts full
buckets no problem. But won?t lift front end most of the time
will some times. The back hoe can pull it?s self backwards
with ease, I guess that because there?s more piston surface
on the pull side of cylinder. Idk any ideals?

steve_in_mo · Apr 18, 2020

Key words "most of the time" might mean you have problems with valves or cylinders leaking.
Also, make sure you are using the right hydraulic fluid. Before you try turning up the
relief valve, you might want to measure the actual operating pressure and compare it to
the original specs for the unit. You might also check the specs for that new pump to make
sure it will put out the kind of pressure you want.

marloweg · Apr 18, 2020

my case was like that new pump all good yet pump looked good if it gets weaker as it gets hotter it's your pump.lots of after market pumps

buickanddeere · Apr 18, 2020

(quoted from post at 03:08:04 04/18/20) I have a ford 3500 loader with backhoe on it, is there a way to
turn up what pressure the relief valve opens? Tractor has a
new pump that?s ran off crank. feed goes to the hoe first then.
from the hoe controls it returns to the loader control valves
. witch feed it, then back into the tank. I believe the relief valve
is opening to easy. If the front tires sink in the ground some
the back hoe can not push the tractor back while digging it
does even put any strain on engine trying, to push it with hoe
like other hoes I have used when trying to ask more then they
could do. it also won?t lift the front tires with loader most of the
time. The loader controls leak when using it but lifts full
buckets no problem. But won?t lift front end most of the time
will some times. The back hoe can pull it?s self backwards
with ease, I guess that because there?s more piston surface
on the pull side of cylinder. Idk any ideals?

You actually know the pressure in psi or you are guessing and are willing to break $$$ components ?

shaun wallace · Apr 18, 2020

There is system relief in hoe control valve along with ones for each cylinder and relief in loader control.

David G · Apr 18, 2020

Put a gauge on before changing anything.

Jhutch · Apr 18, 2020

My plain is to pull the hose off the push pull cylinder to check pressure at the cylinder, on both ends of the cylinder, as it pulls strong so I?m thinking if pressure is equal say 2500 psi on both sides then problem would have to be in the cylinder on the hoe. But on the loader it sounds like it?s bypassing back into the tanks when it won?t left the front end up. As for as fluid goes who knows what oils have been in it. I had some hydraulic oil I had for a case I put in it. I?m not seeing how wrong oil could cause a issue only one direction. Also it?s had this issue ever since I bought it. My buddy bought a old hoe that guy was using burnt motor oil in, as it was old wore out junk wasn?t worth spending money on. It worked like a champ.

buickanddeere · Apr 18, 2020

(reply to post at 21:23:29 04/18/20)

There has to be a relief valve between the pump discharge and the first control valve . Otherwise the pump can be dead headed . Something will have to give/break
Why measure at the cylinder ? Pressure will be the "same" right from the pump discharge to the piston surface in the piston. One pressure gauge in one place will tell you everything .
Cylinder Pistons move faster but with less force from the rod side vs the flat face of the piston side.

Turning Hydraulic relief pressure up on ford 3500?

Jhutch

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steve_in_mo

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marloweg

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buickanddeere

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shaun wallace

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David G

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Jhutch

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buickanddeere

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