Strange Strange lift problem

[mhb@ufe]

I believe they were referring to the draft control spring where the top link connects. The recommend adjustment for that spring is to turn the yoke to where the spring can be rotated with two fingers and a thumb. The draft control is actuated by inward pressure on the top link such as a land plow when it transitions into harder soil.

 

[woodman1928]

Just want to give everyone and update. So last Sunday i finally got to tear into my tractor, drained the fluid, pulled the pto shaft and dropped the pump. After getting it cleaned and dry i pulled the valve. i was wrong i had actually put a new valve in it so i dug around until i found the old valve with the ding that i dropped in a box on the shelf, (i throw nothing out ever).

A closer look at the valve i realized where the chamfer, (the chamfer / taper that goes into the pump) their were deep gouges in it were something was grabbing. When i compared it to the original valve body i realized that chamfer / taper was the wrong angle. it was too steep and was about 1/8" short of were the original one is. Being in my garage i dont have lathe like in my machine shop so i checked it into the drill press and took a mill file and changed the chamfer to match the original. Then i polished it up with 2000 grit emery paper.

I homed the valve bore for a better fit as even after re-tapering and polishing the valve it didn't slide as freely as it should have. After i was happy the valve was moving freely, i moved on to the rest of the pump. I pulled both valve chambers off removed the pistons, cam blocks, Acentric cam roller and the brass shaft bushing. I reassembled the pump with the valve bodys (VALVES STILL INSTALLED), but no internals and reinstalled the pump in the tractor.

Last night i reconnected all hydraulic lines from the front pump and got the tractor filled with fluid and started up.

i was able to open up my flow diverter valve to full flow without the stock pump also trying to work and overwhelm the exhaust port. My front hydraulic pump was much quieter and the system operated well.

i have one of those position control add on from red rock mfg. i razed the lift arms to level put a bord across the arms and jumped up and down on it that also worked perfectly for the first time.

Friday im going to hook up my post hole digger and do a real life test of it installing a fence i need to do.

ill update you all again after the fence test.

Thanks,
Derek G.

 

[Dave G9N]

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

Control spring adjustment is good advise, but It would be much better if someone could provide some additional detail.

I had a similar hydraulic problem and found that adjusting the draft control fixed it. As Mark said, "The recommend adjustment for that spring is to turn the yoke to where the spring can be rotated with two fingers and a thumb. The draft control is actuated by inward pressure on the top link such as a land plow when it transitions into harder soil." I found that it took more than that to make it work on my tractor. Since I have no real idea how much more it takes, I gave the yoke a few turns in and now the lift appears to work properly. Whether it will respond to a sudden load the way it should I can't tell.

After rebuilding the pump and replacing the lift cylinder, the lift tended to go up and stay up without a fairly heavy load. It was jerky and took a lot of force to lower. With no load, it would not lower at all. With a back blade, it would not dig in much at all in dirt, and a 2 bottom plow barely dug in at all. It finally struck me that if the yoke was too loose, the overall length of the shaft and yoke would act like an implement pushing on the top link, which should raise the implement to relieve an apparent overload. I thought that tightening up the yoke would shorten the shaft and stop it from raising on its own. So after 2 minutes work, and a most likely improper adjustment, the lift is operating smoothly. Like a different machine.

It has been about 2 years since I redid the pump, and the tractor has not been used much or much use since then on account of the cranky hydraulics. I mention this because I have read about how hard it can be to unscrew the yoke. After working on several old Corvairs back in the 70s, I developed the old shade tree Corvair mechanic's addiction to anti seize. Hot aluminum, road salt and steel bolts are a bad combination. It has served me well and I wouldn't dream of assembling something as notoriously difficult to disassemble as that yoke without a abundant coating of the stuff. I was still able to turn the yoke easily by hand after several years of outdoor exposure.

 

[G Smith]

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

beautiful work,