Front Loader from a Ford Truck

[GLyford]

If he has any single acting cylinders, he's going to run out of steering fluid unless he puts on a bigger reservoir. The reservoirs on ranger steering pumps are attached, but some of the Dodges had ones where it was attached with a short hose, so it is easier to put on something bigger.

I don't remember if late 80s rangers had serpentines yet, but I know they did by about 1990 so they may have. Kind of why I was suggesting swapping out an AC pump, since it meant less overall messing with serpentine to use something similar to what is there.

 

[rScotty]

If he has any single acting cylinders, he's going to run out of steering fluid unless he puts on a bigger reservoir. .

I thought I'd mentioned that.... but thanks for the reminder. Using a power steering pump will require a larger reservoir. No problem; it's just a matter of a tank and more fittings. The OP is going to be a master of hydraulic fittings by the time he's half way done with this project.
rScotty
rScotty

 

[Doofy]

Yes. Most all pumps will have a direction of rotation arrow cast right onto the body. To make sure of no mistake, the In & Out ports are often labeled. Still, it won't hurt it to spin it backwards for short periods by accident.

Old farm tractors ran their hydraulics at about 2000 psi at 7 to 15 gallons per minute flow. Modern ones and most compact Utility tractors run closer to 3000 psi and about the same flow rate range.

I'd recommend staying in the "under 2000 psi" range for pressure. That keeps things a lot safer and isplenty of pressure for big lifts. My old farm tractor runs only about 1500 psi and 7 gallons/minute to handle round bales (1500 lbs each).

Hydraulic pumps driven by the tractor's PTO shaft that ran at a rather slow PTO speed (100 to 650 RPM was the typical range) were common on old tractors and lasted forever. That's what I used and it would work for your project. But the downside to those pumps is they don't want to be run much faster than about 650 RPM and on an automotive engine that requires some special pulleys or some way to step down the automotive fan belt speed. You might use the existing power steering pump though. More about that below.

Electric hydraulic pumps won't cut it. They are even weaker and not much faster than a power steering pump. Plus they run hot in continuous use.
The basic ballpark equation which ignores all losses but is good for getting an idea of how to match HP to Fluid flow is:
HP = PSI x gallons per minute x 0.0005833

So if you want to run 1500 psi at 7 gallons per minute (about what my old farm tractor does), then that hydraulic pump is going to take 1500 x 7 x .0005833 = about 6 hp to spin it.
Hmmm.....That sounds reasonable. In fact, that's not too far off what an automotive waterpump and fan soak up when working. I'd give it a try with whatever fan belt fits the engine you have. Worse that will happen is that the belt will slip. For that matter, you could even run the whole hydraulics off of the power steering pump but they would be dead slow.
You can use your existing power steering pump and a 5 gallon fluid reservoir to try out your system. It will be slow, but will move the cylinders. All you have to do for that is have some special hydraulic hoses with the appropriate connections made up.
Luck,
rScotty

Great explanations. Thanks.

 

[GLyford]

The OP is going to be a master of hydraulic fittings by the time he's half way done with this project.

He's also going to learn about relief valves, pressure ports, return ports, power beyond, flow dividers, flow controls, hose sizes, and hose pressure ratings.

BIG safety tip: DO NOT use plumbing fittings for hydraulics. Especially cast iron. Plumbing fittings are rated to about 200 psi. Make sure you are using real hydraulic fittings rated to something over whatever your relief pressure is. Your relief pressure needs to be set lower than the lowest rated part in your system. So if you have ONE part, fitting, or hose rated to 1000 psi, guess what, that should be your max for everything. Especially for stuff on ebay, where there are a bunch of cylinders rated dual use air and hydraulic, but only good for a few hundred pounds pressure.

It can be helpful to put a pressure gauge on the input to your valves, where you can see it as you are running. With the system not doing anything, you should not see much pressure at all (assuming you are designing an "open center" system). Even with a relief valve, you can get a pressure spike if you don't have your return to tank set up correctly or there is a block somewhere. You typically will not see the pressure start to rise until the system is working. A cylinder trying to move beyond its full travel counts as work, the pressure will spike up to the relief pressure.

It does not take very long at all for a part working over its rated pressure for something to get damaged. It does not always fail visibly or spectacularly, sometimes it will just cause internal leaks and poor performance...other times there will be sprays of oil at high pressure. If you get oil sprayed under your skin, this is a medical emergency, like 911 and not "maybe I'll try to see my doctor tomorrow."

There is also a hydraulics forum on TBN. Those guys are a great resource if you want to check your system designs as you go.

 

[nimblemotors]

Well, as I was warned by another renter, the landlord can't be trusted, as the other guy's rent went from $50 to $100 to $250 to $500 after he cleaned up and leveled out his space,
and he suddenly becomes a jerk when I start getting rid of that junk. So no immediate need for this loader now. But I would like to build it anyway, just won't be done soon.

I have been looking at hydraulic components. One thing I was thinking about is using a hydraulic motor to drive the truck instead of the engine. Since it has a 5-speed, it would be a total pain
to have to use a clutch and shift 1st to R all the time. So instead of trying to find a auto trans, just replace it with hydraulic motor, and now the engine just runs the pump, which means
it can rev to a higher rpm without effecting the drive speed. I am thinking driving the 5-speed with the hyd motor, which gives me a lot of gear selecting including the low in the 4wd transfer box.

 

[texasranger556]

If you're going with hydraulic drive, I'd get rid of the trans and mount the hydraulic motor on the t-case. Size the pump, motor, valves to give you something like 4-5 mph top speed in low range so you have enough torque to dig, then use high range for transport.

You'll also want to design some sort of governor for the engine. It would be a PITA to maintain engine RPMs and ground speed independently by yourself with hydraulic drive and constantly changing load.

 

[nimblemotors]

It looks like I could do that, with a 3.73 gear and 2.5:1 low in the xfer case, a 600 rpm would yeild about 5 mph, and there is one that will do 600 rpm with 120ft/lb of torque,
which i guess would be enough to move 5,000 lbs...the 2.3L had 82hp and 120ft/lb torque peak.
That would certainly be easier as the engine wouldn't have to be moved from its mounts with the trans gone, room to put in the hyd motor.
It shouldn't be a problem to do an electronic governor for the engine.

 

[GLyford]

One way to do that is an aftermarket cruise control.

 

[aczlan]

It looks like I could do that, with a 3.73 gear and 2.5:1 low in the xfer case, a 600 rpm would yeild about 5 mph, and there is one that will do 600 rpm with 120ft/lb of torque,
which i guess would be enough to move 5,000 lbs...the 2.3L had 82hp and 120ft/lb torque peak.
That would certainly be easier as the engine wouldn't have to be moved from its mounts with the trans gone, room to put in the hyd motor.
It shouldn't be a problem to do an electronic governor for the engine.

I am not sure on the math, but with the tire size of 235/75/15 (circumference of 90.72"), I get:
Direct (4 Hi): 600/3.73=161 RPM at the wheels. Which is 1216 feet per minute, or 13.8 MPH with 448 ft/lb of torque for about 13.7HP to the wheels.
Low (4 Low) 600/6.24=96 RPM at the wheels. Which is 727 feet per minute, or 8.26MPH with 749 ft/lb of torque for about 13.7HP to the wheels.
I might look at something like this: 11.6 cu in White Drive Products 1552A1312BAAAA Hydraulic Motor | Low Speed High Torque Hydraulic Motors | Hydraulic Motors | Hydraulics | www.surpluscenter.com
Direct (2/4 Hi): 367/3.73=98 RPM at the wheels. Which is 744 feet per minute, or 8.45 MPH with 1046 ft/lb of torque for about 20HP to the wheels.
Low (4 Low) 367/6.24=59 RPM at the wheels. Which is 445 feet per minute, or 5 MPH with 1750 ft/lb of torque for about 20HP to the wheels.

That will require ~16GPM at ~2200PSI to move that those speeds.

Aaron Z

 

[texasranger556]

For reference the HST in my tractor is rated max 29 GPM at 6000 PSI, engine speed 2700 RPMs. That works out to 100 HP capacity which is obviously overkill for for a 37 HP tractor, but that ensures I run out of engine power or traction before the transmission "slips". With tractor, loader, backhoe, and foam filled tires it's right around 5000 lbs.

2200 psi at 15 GPM works out to 19 HP of hydraulic power. If you're not in a hurry that would probably work, but keep an eye on oil temp because it will spend a lot of time running over relief which heats up the oil.