Strange Strange lift problem

[woodman1928]

So i restored my 1941 9n now when i did this i converted it over to a live hydrulic system with secondary controls and front and rear aux lines all bent in stainless and i use a bipass flow control madule set to set flow into origonal pump generaly i keep the pto off and run all hydrulics with the front mounted aux lines

First day tested out all the hydrulics and everything worked flawlessly (with no weight on it) lift went up and down front plow worked, back hydrulic too link worked. I was thrilled.

Now literaly on the ride home drom my shop to my house my budy called and asked if i could give him a hand moving a gass miller welder around 650 lbsi said SURE! Get to play with my finished 2 year labor of love! And that weight a good text. I didnt know if it would lift it off the very end of boom pole.

Well hooked up the welder and started lifting just wanted to go up a few inches. Well it just kept going all the way up well for 20 min we just stood their trying to figure out how to to get it to come down then we started tractor and were messing around and i acidently hit my plow lever it release the presure and it dropped.

So got it back home and next day played around with it worked flawlesly with no to weight using anything more than 200lbs on dar bar it would just go stright up.

First i thought it needed adjustment.

Then i thought i did somthing wrong with my live hydrulic system.

So i tryed just disconecting it and running stock pump live hyrulics diconected.

Same damb thing happened. When its under presure its like the control vave gets stuck and even when i move the quadrent i can feel the springs strech but the control valve not move. (With no weight no problem)

What do you guys think? Control valve problem? Exaust valve? Somthing else?

Heres some picks of the old girl below

 

[OldBlue61]

Sorry, I can't answer your questions, but I can admire your work. Looks fantastic!

 

[flembo]

I worked for a major machine tool manufacturing co. I ran a lot of pneumatic and hydraulic piping from 1/4" to 3/4" so I can admire a job well done. That would pass inspection anywhere.

 

[woodman1928]

Thanks, i appreciate it guys. the tractor kinda fell into my lap it was bad (sat in a field that flooded every spring and was fully submerged every year for 2 weeks or so after being crashed into a tree after breaks failed) . Probably as bad as you can get but i decided to bring her back total nut and bolt restore took about 2 years probably would have been quicker but i had a baby in the middle of it! was able to save all the original sheet metal too.

i do hope someone has some ideas about my lift problem though haha

 

[Harry in Ky]

I'm curious about the "plow lever" that was involved earlier. What's that? Next question. You're doing these follow up tests using weight applied where? Just on the lift arms or on the three point as a whole? I'm wondering if the top link draft sensing mechanism could be involved here?

 

[Wdj]

Had similar problem on my 800. Draft control spring adjustment in my case

 

[HCooke]

I assume you know that the 9N only has draft control. Lever on the right side of the seat will raise the rear arms all the way up or lower it all the way down. No position control on a 9N. I can't figure out if all the fancy plumbing will overcome that.

 

[mhb@ufe]

He has instilled linkage that is designed to make it operate as position control that can be seen in the 5th picture.

 

[mhb@ufe]

It looks like you are feeding the tractor hydraulic pump from the return line of the valve and using a flow restrictor to reduce the flow to the pump which could be causing back pressure in the system. Have you tried disconnecting the front pump and operate the three point lift from the tractor hydraulic pump? If it works properly that way I would recommend a flow divider on the inlet side of the valve to feed the hydraulic pump.

 

[HCooke]

He has instilled linkage that is designed to make it operate as position control that can be seen in the 5th picture.

Thanks, I see it now.

 

[woodman1928]

To answer the questions yes i know

1st. Yes i know it only has draft control and no position thats why i have a position control adapter from red rock mfg on the three point to the lever to the handle to give me position control.

2nd the “fancy plumbing” only controls the the two front and two rear aux ports. These are controlled by the secondary spool valve

The way the system works is the front pump sucks from the sump it is pumped up to a bypass flow control valve this limits the flow to 2 1/2 gmp the excess flow is returned back into the tank while the high supply leads up the the spool vlave (witch has its own pressure regulator and return line witch also returns to sump.

in the neutal position the flow passes threw the spool vlave threw a power down streem port to threw a check vlave to the teest prot on the stock pump and out the exaust vlave back to sump. Just like in any live hydrulics mod suck and zang or oldguy mod.

When the spool vlave is activated it devets presure that would normaly be going thew the pump to the selected auz ports.

3rd the weight is being lifted by a boom pole off of the three points using stock lift quadrent and control vlave and eaxaust port and high pressure releaf valve.

I hope that answers the questions

So normaly on these tractors yes there is up and down but you can controll the hight of were you stop it granted it will wander up and down.

Again with no weight it works fine

Put heavy weight on it and it gets weird will go all they way up when i lift up but not go down if i push quadrent qll the way down.

If i release the presure in any way weather i crack the line at the check valve it will isntalty go down.

If there is lighter weight it will go up and if i pu it down it will be a monetary pause and a sharp drop.

Hope iv given enough context to help you help me.

Also i did screw with the draft spring pressure and it did seam to get a little better but not sure.

Thanks Guys!

 

[woodman1928]

Again it does seam like the control vlave literlay dosent move when its stuck at the top you can hear the springs strech and i think the sudeen drop affect is becouse it pops back under spring load and BAM IT DROPS!

 

[mhb@ufe]

The fact that it works properly with no load and not with a load indicates you have a problem with excessive pack pressure when lifting a load. That pressure is preventing the pump control valve from moving to the lowering position.

 

[woodman1928]

The fact that it works properly with no load and not with a load indicates you have a problem with excessive pack pressure when lifting a load. That pressure is preventing the pump control valve from moving to the lowering position.

What could be causing this back pressure?

 

[mhb@ufe]

What could be causing this back pressure?

I can't figure out the way you are reducing the oil flow and excess oil is returning to sump. If you had a flow divider connected to the pressure line from the front pump it would supply the determined amount of oil to the test port and the reminder of the oil flow would feed the added control valve. I also don't understand the purpose of the check valve.

 

[woodman1928]

becose im running off off a front mounted pump that will run 7gpm at 3800rb
Im not using a flow divider im using at verable gpm bypass valve that you can set to only alow the correct gmp to pass to your controls.

Other wise it would overwhelm the system.

But keep in mind in the past i have compleatley disconected this whole aux / live hydrulic system (removed fitting from test port and put stock plug bolt back in the test port and ran it stock) the tractor is still doing this in its 100% stock configuration it has nothing to do with the aux system or live hydrulics.

.

 

[mhb@ufe]

becose im running off off a front mounted pump that will run 7gpm at 3800rb
Im not using a flow divider im using at verable gpm bypass valve that you can set to only alow the correct gmp to pass to your controls.

Other wise it would overwhelm the system.

But keep in mind in the past i have compleatley disconected this whole aux / live hydrulic system (removed fitting from test port and put stock plug bolt back in the test port and ran it stock) the tractor is still doing this in its 100% stock configuration it has nothing to do with the aux system or live hydrulics.

.

I don't recall reading that you ran it stock and had the same problem. All the valves that control the stock system are in the hydraulic pump and I can't think of what in there would create the back pressure. Because it lowers when you crack the line at the check valve proves that you are getting back pressure somehow.

 

[woodman1928]

Yea it was in my inital post that i disconected the system and ran stock and it still did it. Thats why im hear what would cuase thesto k pump setup to do this

 

[mhb@ufe]

The only thing I think of to check at this point is the quadrant adjustment. Disconnect the position control linkage and raise the arms all the way up. Then push the quadrant down until the arms start to lower. It should be 2 1/2 inches + or - 1/8 inch of movement. That adjustment can be changed by loosening the 4 bolts on the quadrant and move it to where you get the proper measurement. This adjustment is normally checked with weight on the TPH but due to the problem you have I would check it with no load or a light load first..

 

[woodman1928]

Ill do that hopefully by the end of the weekend had a bit of a run in with an angary ground nest of yellow jackets yesterday and lets just say im a swollen hurting unit today and probably not going to be working on anything for the next day or two.. Slo someone had mentioned the draw bar spring pressure potently being and issue any thoughts on that?