7500woods backhoe

[jo jo]

Low power, the dealership increased psi , what is max psi on this unit and what could happen if pressure is over max?

 

[Dman1981]

Don’t know max psi but over usually means catastrophic failures down the road cylinders leak booms crack welds break pins and bushings wear faster valves leak
Have seen guys bend dipper rods
I turned them up for years and told them it’s just more money in my pocket

 

[jo jo]

Should the relief valve release pressure?
I thought they would check the valve pins to see if they were sticking, but instead they maxed psi pressure or maybe put shims something other than maxing out the psi, the backhoe only has 300 hrs and the previous owner had some hose's replaced on it , I had that same backhoe before I lost it in a fire and I didn't have to change any hose's until around 900 hrs it worked great this one not so good

 

[Dman1981]

Should the relief valve release pressure?
I thought they would check the valve pins to see if they were sticking, but instead they maxed psi pressure or maybe put shims something other than maxing out the psi, the backhoe only has 300 hrs and the previous owner had some hose's replaced on it , I had that same backhoe before I lost it in a fire and I didn't have to change any hose's until around 900 hrs it worked great this one not so good

Yes it does relieve the pressure but say it set at 2000 and you set it to
2500 say you have a three inch cylinder how much more force are you now exerting on a piece of equipment that was meant for 2000
Most relief are adjustable with shims inside or screws some are even inverted where you take shims out

 

[rScotty]

Yes it does relieve the pressure but say it set at 2000 and you set it to
2500 say you have a three inch cylinder how much more force are you now exerting on a piece of equipment that was meant for 2000
Most relief are adjustable with shims inside or screws some are even inverted where you take shims out

Hydraulic force is just pressure times area. And it's a simple linear relationship. So if the pressure is turned up to 2500 and used to be 2000, the percent gain in force is:
((2500-2000)/2000) then times 100 to turn it into a percent. Comes out to a 25% gain.

Hydraulic pumps normally have an ability to put out over 3000 psi, so the system pressure is regulated by the relief valve. Relief valve settings are easy to adjust.

3000 psi is considered the max psi for most tractor hydraulics. It is accepted by most of the industry as a safety limit for the type of hose and fittings that tractors use.
enjoy,
rScotty

 

[rScotty]

BTW, if you put a hydraulic T fitting on the IN port of the FEL control .... and then mount a pressure gauge there where you can see it you can watch pressure yourself. You can use a 5000 psi gauge from ACE hardware.

My old JD front loader runs about 1000 psi lifting a normal bucket full of dirt. It will go up to about 1250 to 1500 for a difficult break-out. Those older front end loaders tended to get the same force as newer designs by using less compact geometry with slightly larger cylinders instead of more pressure. The old way was less expensive in fuel, fittings, and wear - but cost more to manufacture.
rScotty

 

[Dman1981]

All manufactures have different specs for hydraulics my little kubota is 2000
My 30b is 2500
My terex bh is 3150
Will a dual pump and with a kick out valve at 2900 to save fuel
Nothing is set in stone