Foton 404 Steering is hard/impossible when sitting still

[Wa11banger]

Greg I just did a fluid replacement, I did not flush with any alternate or substitute fluid.

If I did it again and performed a flush with kerosene or something other than the proper fluid how would I remove the contamination of the kerosene in the new fluid?

I would have thought by running the system through with clean fluids and the line open would have removed the ability for any thick fluid to be left trapped in the control box. If I understand this system it is not recirculatory but one hose per cylinder. Would I not have passed all fresh fluids through the control box as it was being bled out the cylinder lines?

 

[greg_g]

What doesn't drain out evaporates. And that's one of the reasons I recommend flushing with kero rather than with diesel. It dissipates more quickly. If you've ever spilled any diesel on the floor, you'll have an idea of how long the residuals take to evaporate. Kerosene is more volatile (jet engines burn it), which accounts for the faster evaporation.

And the blockage that is making your steering hard could actually be in the control box. Ya gotta flush the whole system.

//greg//

 

[Wa11banger]

And the blockage that is making your steering hard could actually be in the control box. Ya gotta flush the whole system.

Thats kind of what I was asking, I would have thought running the fluid through the system from the resevoir to the end of the cylinders would have done that. I was thinking that that was the whole system. Does the control valve have a seperate fluid resevoir? Looking in the manual it does not appear to but this thing has fooled me before

 

[greg_g]

No separate reservoir. Note that there are four steel lines at the controller. Two are supply lines, two are return lines; let's call pressure lines 1 and 2, return lines 3 and 4. The pump supplies the controller. When the steering wheel is in the straight ahead position, there's little or no pressure on any of the four lines. Fluid will circulate, but not under great pressure. Turn the wheel to the right, the controller causes line 1 to become pressurized, and routes that fluid to the cylinder on line 2. The cylinder ram extends, sending return fluid through the reservoir/filter and back to the controller. Turn the wheel to the left, the controller causes line 2 to become pressurized, and routes that fluid to the cylinder on line 1. The cylinder ram retracts, sending return fluid through the reservoir and back to the controller. I might have right and left reversed in this description, but the principle is still the same.

Your test proved that some fluid was flowing, but I'm presuming your nature is not to be wasteful (or messy). That leads to a further assumption that you only checked briefly for flow at those two cylinder ports. So the actual fluid flow in the circuit was perhaps only a few inches. Not sure of the capacity, but let's say the circuit holds two quarts of fluid. You moved a few ounces, so there could still be big chunks in there. My longstanding recommendation for the steering flush procedure involves draining the entire system, and replacing it with kerosene. Close it up, and drive around for several minutes making figure 8s. That will circulate the kero throughout the circuit, breaking up the crud, and carrying it along in the flow. Drain the kero, repeating the flush as dictated by the color of the crud coming out. When it comes out clear, refill with fresh steering fluid of your choice. The filter may also have caught a lot of crud, and may justify replacement as well.

This may or may not fix your problem. But unless/until we know you're working on a clean system, further troubleshooting is at best frustrated. Below is a diagram that may help. It's not specific to the FT404, but pretty close.


//greg//

 

[Wa11banger]

Ahh thank you for that explanation and it explains why we were miscommunucating. I did a complete fluid flush when I bled through each cylinder supply line. I have 2+ gallons of old and clean fluid mix I drained from each side of the circuit. I ran each direction well past clean new fluid coming out not just checking for fluid flow. And I only broke each line after I compressed that cylinder completely so theres only a minimum of fluid I couldn't get out unless I broke the cylinder down.

The steering is greatly improved I am just not certain it's as good as it could be when sitting still.

 

[greg_g]

Ok. Consider then that the steering is still essentially mechanical. That is, the hydraulic system provides "power assist ". So hydraulics aside, perhaps something is binding. Because the steering rod rotates inside a fixed column - and that it disappears through the dash - it's difficult to diagnose a bent steering rod. I don't think yours has a knuckle at the bottom anyway. But the hydraulic cylinder ram however, is much more visible. Turn the steering wheel so that the ram is fully extended, then check with a good straightedge to see if it's true. The pull rod should be checked for true as well. On my Chinese tractors I've experienced two bend hydraulic rams and several bent pull rods over the years. In fact, some members have inserted solid steel rods or smaller diameter pipe inside the hollow pull rods for extra strength.

//greg//

 

[Rich Waugh]

Greg makes a very good point on the bending of the tie bar in these tractors. My Jinma 304 bent the tie bar twice and I finally stuffed a piece of rebar inside it which solved the problem. This is a 2-pronged problem: a metallurgical issue, as the steel tube they use for the tie bar is simply not hard enough and can't be made hard as it doesn't have sufficient carbon in the alloy; a mechanical problem as the front wheels have a high degree of leverage against the tie bar and easily bend it if one front wheel strikes a hard object while turning. Rebar, because it is hard, makes a good insert brace for it. I tried heat treating my OEM tie rod tube with no success, hence I say there is insufficient carbon.

You should check your toe-in on the front wheels and eyeball the tie rod for straightness. If the tie rod checks out with a straightedge then set your toe-in to factory specs to minimize unwanted forces on the tie rod and make the steering as mechanically easy as it can be. If the wheel alignment is incorrect it can make the steering geometry resist turning, but it is easily checked with a tape measure and adjusted by screwing the tie rod end(s) out or in as needed.

 

[Wa11banger]

The steering on this tractor is completely hydraulic no mechanical steering unless I am misunderstanding something.. like on a car, that steering is mechanical with power hydraulic assist. Being that the steering wheel is tied directly to the steering gear box. In the case of this tractor, there is no steering gear box making it completely power only steering.

Rich, although I havent measured toe in as of yet, it appears correct as does the tie bar appear to be straight by eye. Unfortunately toe being out of sorts would be a problem while moving and wouldnt affect standing still operation of turning the wheels.

Steering is great while moving (rolling) even at the slowest of speed either forward or reverse. Only while standing still does it seem to lack ability.

Think about a three point turn in a tight place in your car. You pull into your first point and stop. Then wheel the steering all the way to the stops and back out. There is where I am seeing the difficult steering. I can only wheel about 30 degrees before it seems to dead head and wont turn any further while stopped. But if I am rolling no matter how fast or slow just moving period,I can one finger turn the wheels until the inside edge catches the forward bar on my loader.

Also engine RPM doesnt seem to factor into it. No change from idle or set to 1800ish RPM.

 

[KoonHunter51]

Wa11banger,
Did you remove a line at the PS cylinder to drain/flush & did you fun/flush until lines/reservoir/gearbox were empty, or did you just keep adding fluid until clean ?
Is your PS reservoir separate & in front of the radiator, or other location ?
I do not see a filter in my reservoir.
I have a 30 hp Jinma I was going to drain, flush & fill, as I have limited PS when low RPM.
David

 

[Wa11banger]

Hey koonhunter.. I set the steering all the way one direction. I loosened the banjo fitting right at the steering cylinder to drain while running. Stuck the hose in a bucket, started the tractor again and turned the wheel to run fluid out. I stopped every so many seconds and topped off the reservoir and kept going till it was clear. I never let it get too low. Make sure you do the flushing on each side with that cylinder colapsed to get the most old fluid out.. My reservoir is about the middle top of the right side of the engine about a foot above my pump.. it has a cylindrical filter that drops down into it through the fent/fill cap, probably 4" long and somewhere around 1.5" diameter. Still going strong since doing this