J.D. 720 Diesel Power steering

~The most likely place is in the steering sleeve area [possibly a loose, worn, or missing pin, or worn cam, or excess end play].

~You might want to start with a steering vane leakage test [both directions], that will eliminate a lower vane leakage problem. BUT, I don't think you problem is in the vane area though as it steers better when you hold the steering shaft forward.

~My suggestion would be to get the Deere steering repair manual & work your way thorough all the test & check procedures.

~We could probably get you a little closer to the cause if we knew the history of the problem & when it last worked correctly & how it acted as the problem became more pronounced.

~You might try increasing the flow rate by adjusting the flow control valve,,, if that helps your problem suspect a cam problem, or one of the pins has worn a notch in the side of the cam slot, or there is a notch worn in the sleeve at a pin interface. [does it steer better to the problem side when on a slick surface with little front tire traction & get worse when the front tires are on pavement?]. When you hold the steering shaft forward that could be helping a pin slide by a worn spot in a sleeve slot.

~Because you have a 720D we really don't know if you have the early or late steering sleeve in it [makes a difference in the problem area & how to adjust it] . There is a S/N break, but because of the age of the tractor in a lot of cases there has been some parts interchanged over the years. If it has a helix set screw it's an early system,,,if it has an end play adjusting bushing on the front of the worm it has the late system..

~If you can furnish a little more information on the history of the problem we might be able to point you down the correct path to finding the root cause without a complete system disassembly�

~About all I can tell you is more than likely the problem is in the steering sleeve, or cam on the rear of the sleeve, & in most cases it is wear on the pressed in pins or the slots the pins run in.

Amen to the cam or pin wear, but what do you think the odds are that he might have a sticky steering valve ? I've heard that they can sometimes develop burrs which might interfere with the bore.

Since he says the steering is erratic, and that pushing inward seems to help, could he actually be pushing the steering valve arm which is helping to move the steering valve ? Of course this would only help in one direction. I wonder if you pushed the steering column, would it steer better in one direction, and if you pulled on it, would it steer better in the other ? If pushing only helps, it sure sounds like flats on the pins and or cam surface, which is probably where the problem lies.

See, you helped me to get through mine, now I have opinions !

Frank-in-Tallahassee
70D // 855