measure hydraulic pressure at any fitting?

[JCoastie]

No clue how the 3pt works, does it have an internal cylinder? When you change the hydraulic fluid, should the 3pt be up or down to have the most fluid in the reservoir while draining?

Just saw a picture of a very big tractor that had 2 external hydraulic cylinders and with those, the 3pt would be in the down position with fluid out of the cylinders. Same with smaller tractors without external hydraulic cylinders?

 

[WranglerX]

IF its a open system the 3PH is a captive pressure lifting the implement behind the valve, system pressure will be at pump pressure if its below system relief valve or at system pressure if pump is over driven and pump put pressure is above relief valve setting.... But this concept only works if there is some restriction to flow to build pressure in system..... Bumps in the road will have no effect on pressure in system if pressure in 3PH ram is behind the 3PH valve ....

 

[LouNY]

No clue how the 3pt works, does it have an internal cylinder? When you change the hydraulic fluid, should the 3pt be up or down to have the most fluid in the reservoir while draining?

Just saw a picture of a very big tractor that had 2 external hydraulic cylinders and with those, the 3pt would be in the down position with fluid out of the cylinders. Same with smaller tractors without external hydraulic cylinders?

The same with internal cylinders, it takes fluid under pressure to extend the internal one way cylinder and lift the arms.

 

[JCoastie]

gauges arrived today, as expected, same pressure from rear remotes and 3rd function.
Little bit of parallax from the 3rd function image, but they are same viewed head on. Set perfect from the factory.
And I see a crack in the newest hose on the tractor, a Tractor Supply hose for the top-link. It's only 24 months old and the tractor sits in a covered carport!

Parts used were $38 all from amazon

Amazon.com

www.amazon.com

Amazon.com

www.amazon.com

Amazon.com

www.amazon.com

 

[WranglerX]

Tractor Supply is the Horror Fright of the tractor world....

 

[Smokeydog]

Using a gauge to measure the your dead head or maximum pressure is useful information. What your pump can provide and what your relief valve will allow. Tractors can have multiple pumps, relieve valves and circuits.

Installed a Kubota soft ride system on the M59 FEL that uses hydraulic accumulators to dampen shock loads. Simple ball valve allows it able to turn the system on or off. Added a pressure gauge to be able to monitor working pressure. Can always check dead head pressure to the loader circuit. My relief pressure is a little lower than spec but the loader is incredibly strong anyway. Seeing how much pressure it takes to lift a load is interesting. Watching and feeling how the soft ride system dampens moving heavy loads is remarkable. What got me by surprise was the dynamic loading of the hydraulic system. Circuits downstream from the control valves and not relief protected.

Example, grubbing up a stump. I can use the bucket or grapple to try to lift the stump up to dead head pressure of 2800psi. This gives about 3800# lifting force. If I curl (separate hydraulic circuit) and push with tires I can see the lifting pressure almost double. That is almost doubling the lifting force. All what designers and engineers have to take in account. What operators can understand to better utilize and care for their equipment.

 

[JCoastie]

This gives about 3800# lifting force.

Jealous of that capacity, mine is about 2k#. On occasion (more than I'd like due to wife's changing weekend ideas) I carry a pallet of blocks and/or bricks around the yard. On a few occasions, it's more than I can handle, and definitely depends on how they are loaded. Ideally low and flat on the pallet, but that puts the weight out too far, so stacked higher and stepped on a pallet, I can lift them ... even higher when the fall off, as my yard is bumpy lol

 

[Fallon]

No clue how the 3pt works, does it have an internal cylinder? When you change the hydraulic fluid, should the 3pt be up or down to have the most fluid in the reservoir while draining?

Just saw a picture of a very big tractor that had 2 external hydraulic cylinders and with those, the 3pt would be in the down position with fluid out of the cylinders. Same with smaller tractors without external hydraulic cylinders?

Yes, there is an internal cylinder for a 3pt, if there aren't external ones. My L4060 has a pair of external ones.

There will be less oil in a collapsed cylinder than an extended one. A single acting cylinder like on a 3pt (lift only, gravity retract) will have very little oil in it. Double acting cylinders (power extend & retract) like on any modern loader will have less oil in them retracted, but still a fair bit of oil in each end.

You'll never get all the oil out of the cylinders or lines when changing fluid, so don't wory about it to much. Retracting cylinders would help a bit.

Most manuals specify checking oil level with loader & 3pt lowered to the ground.

 

[Dman1981]

That’s some funny **** there
Thanks for making my day

 

[LD1]

Pascals law. Yes pressure is the same everywhere unless you isolate one of the circuits. But they are all feeding from the same pump, and using the same relief valve. So deadheading the hydraulics (to take a max pressure reading) will be the same no matter where you take the reading.

Restrictions from fittings, couplings, etc only create a pressure drop when there is FLOW.