Loader hydraulic too powerful

petertay

Member
The tractor is an NAA with a Freeman loader from that era. The front PTO driven Hyd pump was shot so has been replaced. The problem is that the loader leaps up in the air when the lever is pulled, even if just barely touched. Apparently the new pump moves a lot more fluid than the old one.

The loader has very limited use as it wont move up slowly. It literally jumps up a foot in a split second. Replaced 1/2 inch the pressure hose with 3/8, but that did not help.

Any ideas? Some sort of reducer? --Thanks
 
more of a wrong GPM pump.. vs pressure. 2500 psi is a common ag pressure.

He might have had an 8-12 gpm pump before and now has a 16-20 gpm pump.

the owner can reduce rpms and thus reduce flow, and try to feather the spool a bit more...

One thing i'd check is to make sur ethe valve is rated for the flow from the pump. if they are not a good match.. the pump will not like it as much.. however it sounds like the valve is NOT an issue. you can also get restrictor orifices and even 1-way restrictors that are full open in the other direction.. just be carefull with restrictors..
 
I sound like a broken record telling you that I am not a hydraulic
expert, but I'm not. You'd think I'd just stop answering hydraulic
questions, but that would be smart of me, and, well......

Anyway, a restrictor would probably be what you're looking for,
adjustable if you can find one.

I had a Case 930 CK that someone had cobbled an 8N sized loader on.
That tractor had two pair of remote outlets, a category II 3pt
hitch, a 15GPM flow rate and held about 16 gallons of hydraulic
oil if I remember correctly. Loader was way to fast both up and down.

The previous owner had put a standard old ball valve in the line,
removed the handle and used a screwdriver to adjust the flow rate.
It worked, but I always wondered about back pressure etc.
I didn't keep it long enough to have trouble with it.
 
Learned over a decade ago to understand GPM and PSI. On most tractors and loader you want around 8-10 GPM and 2000-2500 PSI. Sounds like you have a 15-35 GPM pump which can and will get you or others hurt due to the fact it can and will flip you tractor. Time to either send it back or or get a flow re-stricter
 
Another thought, I want a higher volume pump for my
NAA.
If the mounts would work for both of us, I'd trade.
 
(quoted from post at 19:42:58 08/08/14) The tractor is an NAA with a Freeman loader from that era. The front PTO driven Hyd pump was shot so has been replaced. The problem is that the loader leaps up in the air when the lever is pulled, even if just barely touched. Apparently the new pump moves a lot more fluid than the old one.

The loader has very limited use as it wont move up slowly. It literally jumps up a foot in a split second. Replaced 1/2 inch the pressure hose with 3/8, but that did not help.

Any ideas? Some sort of reducer? --Thanks

Sounds rather odd.

Lift rate is linear with flow rate. If you double the pump volume you halve the lift time. So to go from say a 10 second lift time to a 5 second lift you would need 2X the volume. From your description sounds more like a 10X or more increase which would be a HUGE increase in pump size!!!!

It would be helpful if you could provide some empirical data rather than the rather vague description. Start with a part number for your new pump along with the size of the cylinders and the actual length of time it takes to fully extend the lift cylinders.

If your pump really is that much oversize you could add a flow divider but by the time you figure the cost of the divider and added plumbing it's probably cheaper to buy a $100 pump with the proper flow rate.

TOH

PS> The Freeman Thousand series loaders used either a 9 or 18 GPM pump with 1-3/4", 2", or 2.5" x ~30" stroke lift cylinders which makes this sound even stranger.
 
Thanks for for the replies. To answer any questions about the pump itself, I"d have to dig through receipts from two years ago. But I did buy it (online) from an ag pump dealer who sold it as the correct pump for the application.

The cylinders appear to be not original. They are three feet long with the rods being 1 5/8 inches diameter. The valves are of unknown origin. The whole system is cobbled together with the oil reservoir hanging out front of the radiator.

mvphoto9963.jpg
 
(quoted from post at 09:46:14 08/09/14) Thanks for for the replies. To answer any questions about the pump itself, I"d have to dig through receipts from two years ago. But I did buy it (online) from an ag pump dealer who sold it as the correct pump for the application.

The cylinders appear to be not original. They are three feet long with the rods being 1 5/8 inches diameter. The valves are of unknown origin. The whole system is cobbled together with the oil reservoir hanging out front of the radiator.

mvphoto9963.jpg

Your photo shows a valve with ONE connection. There is NO connection to any of the work ports or a return to the tank from the valve. What's up with that? I fail to see how that could possibly work in any fashion. There is no way to send oil to any cylinder or return oil to the tank.

Unless you have something mighty unusual in the way of hydraulic components the valve should be plumbed for open center operation. The RETURN port on the right side of the valve needs to be connected to the reservoir and the quick connect on the work port needs to be connected to the lift cylinder. That should work fine.

The "standard" operator convention for lift cylinders is to pull back on the lever to raise the loader and push forward to lower it. Your quick connect is in the forward work port which means yours would operate backwards to that - you would push forward to raise and pull back to lower. Move the quick connect to the rear port if you want the standard behavior.

IF you connected the lift cylinder to that valve as it is currently plumbed you would have dead headed pump pressure (3000+ PSI) behind the spool and I can easily imagine that the loader would raise very abruptly when you initially shifted the spool but without a return line there would be NO WAY to get it to lower????

You need to provide a COMPLETE description of ALL of the hydraulic connections as they are when the loader is behaving as you described. I think it is safe to say the problem is the plumbing - not the flow rate.

TOH

PS> Keep running that pump dead headed into that valve and you will QUICKLY need a new pump. Makes me suspect that was the fate that befell the original pump....
 
TOH: Thank you for taking the time to help.

About the return: it doesn"t show in the photo because it exits
out the bottom of the valve assembly. There is a filter cartridge
hanging there, then a return line. Old and rusty. Appears to
have been that way forever.

About the pump, the reciept shows:
L827-10X-LB Front Loader Pump
Ford 8n NAA 600 + Massey Ferguson
Item 360432046151

Now here"s an oddity. It DOES lift when the lever is pushed
forward, so I have standard operation. BUT, when I bought it, it
ran the other way, so I switched ports with the quick connect and
the presure line to reverse the operation to standard.

Description of plumbing: The pump has 1-inch ports reduced to
3/4. Then to 1/2 inch. The pressure line runs to the spool as
shown in the photo. The return line runs through the filter back
to the tank. Sorry about the misleading photo which shows an
empty quick connect. That"s where I put in the 3/8 line
mentioned in the OP. The 3/8 line runs down to a Tee which
goes to both cylinders.

Again, thank you. --Peter
 
(quoted from post at 08:03:14 08/10/14) TOH: Thank you for taking the time to help.

About the return: it doesn"t show in the photo because it exits
out the bottom of the valve assembly. There is a filter cartridge
hanging there, then a return line. Old and rusty. Appears to
have been that way forever.

About the pump, the reciept shows:
L827-10X-LB Front Loader Pump
Ford 8n NAA 600 + Massey Ferguson
Item 360432046151

Now here"s an oddity. It DOES lift when the lever is pushed
forward, so I have standard operation. BUT, when I bought it, it
ran the other way, so I switched ports with the quick connect and
the presure line to reverse the operation to standard.

Description of plumbing: The pump has 1-inch ports reduced to
3/4. Then to 1/2 inch. The pressure line runs to the spool as
shown in the photo. The return line runs through the filter back
to the tank. Sorry about the misleading photo which shows an
empty quick connect. That"s where I put in the 3/8 line
mentioned in the OP. The 3/8 line runs down to a Tee which
goes to both cylinders.

Again, thank you. --Peter

OK - return out the bottom and the other line was hooked up to the coupler.

Since the pump is a fixed displacement going from a 1/2" to a 3/8" hose isn't going to substantially decrease the flow rate. It will simply increase the speed at which the fluid flows through the line and generate more heat and power loss in the plumbing.

Standard operation is for the loader to raise when the lever is pulled backwards and drop when pushed forward. To plumb it opposite that is not the norm but that is a "preference" and not your problem.

The pump is the "standard" loader pump sold right here and used on a gadzillion of these old loaders. YT says it produces 14 GPM @ 2000 RPM. Since flow rate is directly proportional to engine RPM the flow rate at 500 RPM (idle) is 14/4 = 3.5 GPM and at 1000 RPM 7 GPM. Do you get the same jerky behavior at lower engine speeds? See where I am going?

TOH
 
Take pictures of the entire setup. As detailed as possible. Hydraulics are not that complicated when you understand it.

I just finished putting new lift cylinders on my unit. Didn't like the two handle setup so installed a joystick.

I'm not an expert either but the guys here will certainly find the problem given enough info. Pictures are the best.

Start at the pump and show the supply line to the spool valve. The the lines to the cylinders.

Good Luck

BigDawg
 
Yes, I see where you"re going. Just tried it. At 500 RPM it is
nice and slow. At 900 it"s twice as fast. At 1200 it jumps.

When I"m plowing snow with a heavy V-plow, and the engine is
at high speed, I lift and lower the plow at that speed. At least I
hope to. Going through a 24-inch drift may require lifting the
plow a bit, but when it jumps up, it seems as if it"s tearing
things apart.

BTW: about plowing snow on a hilly lane: it has wheel weights
and chains, but the poor little thing is so light, we just had the
tires fluid filled. This also helps when pulling logs up a grassy
slope. Fun little tractor.
 
(quoted from post at 18:19:49 08/10/14) Yes, I see where you"re going. Just tried it. At 500 RPM it is
nice and slow. At 900 it"s twice as fast. At 1200 it jumps.

When I"m plowing snow with a heavy V-plow, and the engine is
at high speed, I lift and lower the plow at that speed. At least I
hope to. Going through a 24-inch drift may require lifting the
plow a bit, but when it jumps up, it seems as if it"s tearing
things apart.

BTW: about plowing snow on a hilly lane: it has wheel weights
and chains, but the poor little thing is so light, we just had the
tires fluid filled. This also helps when pulling logs up a grassy
slope. Fun little tractor.

Certainly sounds like you need to reduce the flow but you are still giving subjective descriptions. Give me something empirical. At ~1500 RPM engine speed how long does it take to lift the loader from the ground to full height? As a data point the Model 730 Ford loader had a full lift height of 10'-5". The unloaded lift time with a 19 GPM pump was 2.6 seconds and with the 14 GPM pump it took 3.6 seconds. That works out to 3-4 feet per second which is pretty snappy. What is the lift speed on your loader?

TOH
 
My lift times for the full ten feet are similar to what you mentioned:
500 RPM - 9 seconds
1200 RPM - 3 sec
1500 RPM - 2.5 sec

Think that Northern Tools reducer mentioned by ScoutB would
allow a decent lift rate while running at higher speeds such as
plowing or moving dirt?

Thanks again.
 
(quoted from post at 10:33:47 08/11/14) My lift times for the full ten feet are similar to what you mentioned:
500 RPM - 9 seconds
1200 RPM - 3 sec
1500 RPM - 2.5 sec

Think that Northern Tools reducer mentioned by ScoutB would
allow a decent lift rate while running at higher speeds such as
plowing or moving dirt?

Thanks again.

Nine seconds is way too slow for my taste and 2.5 seconds is PDQ. Sort of like porridge - too hot or too cold ;-)

If I used a flow restrictor it would be in the [u:c04e334ae6]lift cylinder work circuit[/u:c04e334ae6] - not the pump supply line coming to the valve. The restrictor is going to create a substantial back pressure in the circuit and I wouldn't want the pump running full time into that sort of load for the very good reasons ScoutB gave you. I'd also use a one way restrictor so that you don't slow down the speed at which the lift drops. Here is a nice adjustable one that is a bit cheaper than the one from Northern Tool: [u:c04e334ae6]Prince Flow Reducer[/u:c04e334ae6]

TOH
 

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