Hydraulics maximum load

NMNeil

Member
After a full rebuild of my 49 8N I wanted to put it to work and I was offered a class 1 home built 2 row ridger which looked perfect.
Now this thing is heavy, and I mean it took an engine crane to attach it to the tractor, it's that heavy.
And now the hydraulics won't work with it attached, so the question is, does the 8N hydraulics have a load/weight limit?
 
After a full rebuild of my 49 8N I wanted to put it to work and I was offered a class 1 home built 2 row ridger which looked perfect.
Now this thing is heavy, and I mean it took an engine crane to attach it to the tractor, it's that heavy.
And now the hydraulics won't work with it attached, so the question is, does the 8N hydraulics have a load/weight limit?
Add an OIL gauge to a port on the top cover..or possibly on the bottom of the pump housing. Try lifting the load...read the gauge..
 
After a full rebuild of my 49 8N I wanted to put it to work and I was offered a class 1 home built 2 row ridger which looked perfect.
Now this thing is heavy, and I mean it took an engine crane to attach it to the tractor, it's that heavy.
And now the hydraulics won't work with it attached, so the question is, does the 8N hydraulics have a load/weight limit?
There are pictures on this site (in the archives) showing the front end of the tractor raising up when the 3 point load is too heavy! Doesn't sound like that is your case. Check the pressure like the other poster suggests and remove the right inspection port to observe what happens when you attempt to raise the lift.
 
After a full rebuild of my 49 8N I wanted to put it to work and I was offered a class 1 home built 2 row ridger which looked perfect.
Now this thing is heavy, and I mean it took an engine crane to attach it to the tractor, it's that heavy.
And now the hydraulics won't work with it attached, so the question is, does the 8N hydraulics have a load/weight limit?
There are "NO" quick fixes .......See pictures.......ALL POSITIVE DISPLACEMENT pumps must have a RELIEF VALVE.
The "N" tractors did not have today's oil PSI,and or area of the Piston inside the lift cover..
Force= PSI X AREA
Force
is the weight of the three point attached implement...
PSI, is the oil pressure out put of the oil PUMP....often controlled by the oil pump RELIEF VALVE..
Area, is the area of the face of the PISTON (inside the top lift cover)...
Once you KNOW the OIL PUMP discharge PSI...with a gauge attached to the oil supply port...
Once you know the diameter of the internal lift PISTON,calculate the area of the piston.., Area = 3.142 X (R x R)
Then Multiply the area by the OIL PSI and that will tell you the theoretical weight of the implement that the three point can lift.
Estimate the weight of the three point impalement ..IE..600 Lbs per cubic Foot..
Again there is NO magic SNAKE oil FIX
 

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After a full rebuild of my 49 8N I wanted to put it to work and I was offered a class 1 home built 2 row ridger which looked perfect.
Now this thing is heavy, and I mean it took an engine crane to attach it to the tractor, it's that heavy.
And now the hydraulics won't work with it attached, so the question is, does the 8N hydraulics have a load/weight limit?
Yes they have a limit and its governed by the maximum hydraulic pressure your pump can produce.

There is a hydraulic test port on the bottom right corner of the pump. Remove the plug (1/2-20 thread) and connect a 3000 PSI pressure gauge to the port. Now start the tractor, set engine speed to 2000 RPM, and try to raise the implement. If the pressure reading is 1500-1600 PSI the implement is too heavy for the 3pt. If the pressure is lower than that the hydraulic system is not up to specification.

Dan
 
Thanks for all the replies, but just to add I looked up on an on line calculator for the weight of the main steel beam used, and with a bit of estimation for the rest the implement it weighs about 400 pounds in total. Would that be too heavy before I start looking at pressures?
 
Yes they have a limit and its governed by the maximum hydraulic pressure your pump can produce.

There is a hydraulic test port on the bottom right corner of the pump. Remove the plug (1/2-20 thread) and connect a 3000 PSI pressure gauge to the port. Now start the tractor, set engine speed to 2000 RPM, and try to raise the implement. If the pressure reading is 1500-1600 PSI the implement is too heavy for the 3pt. If the pressure is lower than that the hydraulic system is not up to specification.

Dan
Dan's method is best, as it DOES take into account the linkage geometry. I will add that any attachment is going to have rear overhang. As an example a 230# man on a 10 ft pipe attached to lift arm will get the front wheels off the ground. Directly over drawbar, all in perfect order it will lift 1000 to maybe 1100#.
 
It should lift 400 pounds with no trouble. I would pull the right hand side plate like suggested and look for leaks first off. I have a one armed loader and it i try to lift too much the right real tire will lift off the ground. I assume you had the PTO engaged.
 
Took the side plate off and checked the adjustment as per the manual and it was fine, the PTO is engaged and I did a complete overhaul of the pump during the restoration.
The main cross bar is 2.5" x 2.5" x 8' solid (170 pounds on it's own), took that off and everything works fine, so shopping for some 2.5 x 2.5 x0.25" box section Monday :giggle:
Again, thanks for everyone's help.
 
After a full rebuild of my 49 8N I wanted to put it to work and I was offered a class 1 home built 2 row ridger which looked perfect.
Now this thing is heavy, and I mean it took an engine crane to attach it to the tractor, it's that heavy.
And now the hydraulics won't work with it attached, so the question is, does the 8N hydraulics have a load/weight limit?
Shortly after getting my tractor I clued in to what was wrong when I tried to lift something very heavy. I had to increase the engine RPM. :)
the other day I loaded my carryall with very heavy maple blocks while the carryall was up in the air. The hydraulics starting squealing until I lowered the carryall a little. A very slow leak in my hydraulic hose became a slow drip because of the overweight then stopped dripping under subsequent normal loads. One of these days I'll fix that hose.
 
my recently rebuilt pump with new piston and cylinder will easily lift my ballast box that is over 800lbs. I weighed each piece before it went in and scaled the box when i built it. I would suggest trouble shooting and fixing your tractor as the others suggested before i would modify an implement to work
 

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my recently rebuilt pump with new piston and cylinder will easily lift my ballast box that is over 800lbs. I weighed each piece before it went in and scaled the box when i built it. I would suggest trouble shooting and fixing your tractor as the others suggested before i would modify an implement to work
Its so much easier to simply believe than it is to screw a gauge in and know..:rolleyes:

Dan
 
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my recently rebuilt pump with new piston and cylinder will easily lift my ballast box that is over 800lbs. I weighed each piece before it went in and scaled the box when i built it. I would suggest trouble shooting and fixing your tractor as the others suggested before i would modify an implement to work
That pretty well covers it......:)
 
After a full rebuild of my 49 8N I wanted to put it to work and I was offered a class 1 home built 2 row ridger which looked perfect.
Now this thing is heavy, and I mean it took an engine crane to attach it to the tractor, it's that heavy.
And now the hydraulics won't work with it attached, so the question is, does the 8N hydraulics have a load/weight limit?
Just remember the farther back of the 3-point arms that the weight extends the less weight the system can lift!
 

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