To 20 hydraulics not working

I bought it knowing 3ph would not lift implement.take off implement and arms would
raise.I pulled side covers and saw no telltale signs of a leak.I bit the bullet and
bought new chambers,complete rebuild kit,relief valve,control valve,lift cylinder and
piston. So now lower arms raise my 300 lbs on drawer but if I put any implement on
lower arms come up until weight gets on toplink.Then it stops! I can help it raise by
lifting the implement manualy..kinda taking some of the weight off the tractor.Any
ideas??? Draft spring is free and set right according to manual.And I am running 90wt.
N-series fluid from TSC.

I've been fighting what sounds like the exact same symptoms for almost six months. I'll suggest something is out of sorts with the draft control spring assembly, based on your remark about the lift arms functioning as they should but everything going to pot as soon as the top link loads up.

I finished buttoning mine up for (I hope!) the last time this morning and it seems to be working great now. Problems I noted in mine and corrected along the way include the following:

Item #9: This plate was corroded and bent outward.
Item #8: Missing. I made a new one from polyurethane. Dimensions are found in the parts book.
Item #7: Badly corroded.
Items #6 and #5: badly corroded and stuck inside the spring as a result of brush painting a number of years ago.
Items #3 and #10 were rust welded together and replaced with new matched components.






I slathered everything in this assembly with grease prior to installation and will disassemble and repeat every six months from now on. The adjustment that worked for me was screwing #3 down onto #4 until it took considerable force with one hand to turn #4. That's when the whole system started behaving exactly as it should, lifting implements, holding them wherever I stopped in the travel, and drifting them back down when I lowered the control lever.

You may also need to adjust the quadrant assembly, but I'd pick the draft control spring assembly thoroughly apart first.

Tried your spring idea..did not work for me.

There are at least two ways I know of to override the draft control on these tractors. If either/both work, I think it pretty well isolates your problem and allows you to focus attention directly on where it's needed. No sense bouncing around through the whole system looking for a cure, as I'm so often guilty of.

This photo shows my draft control linkage/toggle/whatever-you-want-to-call-it as configured for draft control. Looks almost exactly like everyone else's setup, right?





With the top link unhooked, pull this pin:





There's only a boom pole mounted on mine, so I just picked it up a bit and sat it across my thigh while I pulled the pin.

Now connect a light implement to the tractor as shown in the configuration below. Something like a boom pole, light-duty grader blade, or something similar in weight. Connecting to something like a large bush hog or backhoe attachment will likely teach you more than you ever wanted to know about the intricacies of welding cast iron...





If your tractor lifts the implement normally, the problem is somewhere in the draft control mechanism.

A second way to bypass draft control is to remove the dipstick-side inspection cover (my preference, as you retain the ability to shift the PTO in and out of gear) and manually assist the fork assembly forward with a long screwdriver as you're trying to lift. The lower fork being hinged on the upper allows you to override the draft control mechanism with very little force. It's just customary to include this with any such a suggestion as this, so here:

DO [b:e7a7d8a3da]NOT[/b:e7a7d8a3da] STICK ANY PART OF YOURSELF THROUGH THAT INSPECTION COVER WITH THE TRACTOR RUNNING!!!

You'll want to keep a firm grip on that screwdriver, too. I mean, nothing in there is going to jump out and grab you but there is a live PTO shaft running right through the middle of all this.

I have it adjusted right now to manual specs..can turn it with thumb and forefinger
with implement attached.But I will tighten it and try.It was seized before I rebuilt
the hydraulics but I freed it..sand blasted it..and gooped it with anti seize before I
assembled it. Tried to adjust quadrant all ready.No luck with that.

Did any of you have the lift control cover off? I'm into one now and where the pipe comes to the top from the pump, there was a short pipe with 2 o-rings on it that fits between the casting and the top cover. The short pipe is split and I cant find another one.
Thanks

For a TO20? The pipe is a Stand pipe. High pressure tube.mine didn't have rubber o-ring.I think that the TO30 does.As far as a replacement I think it just a generic high pressure line

Tried to tighten it..still no lift.For another little test I did lift the grader
blade...well I had to help the 3ph lift it...And left it up.Next day was still in the
air just as high as the day before.So I would say the piston and cylinder are in good
condition!