Foton 404 Steering is hard/impossible when sitting still

[Wa11banger]

Hello all, as stated in the topic I have a new to me 2004 Foton 404 4wd with a Koyker loader that I think is having a steering issue.

I have been practicing and learning the tractor and basic overall familiarizing myself with it and noticed yesterday when I was in a tight area (required about a 7pt turn) that when sitting still I cannot turn the front wheels. Now I was in 4wd/clutch in/brake on/ with about a half bucket load in when I first noticed it. I dumped the bucket and tried again still could not turn the wheels.

Now it seems to work just fine when moving, as soon as I get moving the wheels turn fine and relatively easy stop to stop with little or no effort. If I pick the front up with the bucket it turns fine as well with no noises or anything happening I would consider out of the ordinary.

The only thing I didnt try was without it in 4wd. I will try that tonight and see if that makes any difference being as I am sitting still.

Thanks again in advance for any advice or help in which way to go for troubleshooting

Rick

 

[Rich Waugh]

I'd guess that you may be a bit low on hydraulic fluid in your power steering. Be sure the reservoir is filled and also try raising the engine rpm a bit when you turn. Your steering pump may not be putting out quite enough pressure/flow at idle to power the steering cylinder sufficiently to overcome the deadweight and friction.

It is also very possible, given the age of the tractor, that your steering cylinder may be bypassing fluid past the piston seals. At higher engine rpm this will be less of a problem as enough will stay behind to provide power, but at idle enough of it is bypassing to prevent the cylinder from developing the pressure differential to push the piston. This is a common problem and easily and cheaply remedied. You can order a cylinder rebuild kit from a Foton dealer or check with a local hydraulic supply place to obtain the correct sized O-rings and seals. Most of them are fairly standard metric seals and rings so you shouldn't have a problem sourcing them. If not locally, then through McMaster-Carr or MSC Industrial Supply online.

 

[Wa11banger]

Thank Rich,
fluid is slightly high nothing serious but approximately 1/16th inch maybe. I did try it both at idle and with the rpm lever set at about 1500 rpm. Im thinking about breaking on of the lines and checking the pressure to the steering ram. Is that a good place to start.

 

[Rich Waugh]

If you have a pressure gauge you put on the steering pump that would give you something in the way of hard information. You may be able to feel/hear the fluid bypassing in the steering cylinder if you get someone else to turn the steering wheel while you feel the cylinder shell at either side of where the piston is. A mechanic's stethoscope will allow you to hear fluid if it is bypassing the piston seals, too.

You can, if you want, dismount the cylinder from the tractor while keeping the lines attached and then check its power by extending it between a framework of 2x4s bolted together to fit it. It should easily tear the wood apart at idle. If it doesn't, then you're losing power somewhere, either to bypassing past the piston or a weak pump.

 

[Wa11banger]

I think its the pump.. reasoning is I did another test where I left the wheels on the ground, put rpm to 1800, and then turned the steering wheel till it stopped turning the wheels and got very stiff (approximately 3" of wheel turn). I then grabbed the steering wheel and turned hard. It was very hard to turn but it did and the wheels did not. This makes me think the pump is dead headed at that pressure. Am I on the right track.

 

[Rich Waugh]

No, that sounds more like a problem with your steering motor (valve).

 

[greg_g]

What kind of fluid did you put into the PS reservoir?

//greg//

 

[Wa11banger]

What kind of fluid did you put into the PS reservoir?

//greg//

Unfortunately that is unknown at this time it still has the fluid that was there when I bought it. Also it didnt seem the have this problem when i bought it, it has just started to appear over the last couple of days.

I have wanted to replace it (reason for asking all the questions about fluids in the other posts) and intend to follow your advice and put AW32 in it. The fluid currently in there is caramel colored but doesn't seem to have a lot of particulates just that color.. I had always thought hydraulic fluid was reddish or clear. I have been researching the best way to flush the entire systems and haven't found a clear answer yet.

Best I can tell from information online is I need to remove the line from each cylinder and cycle them by hand to remove the fluid in them then start tractor and put both lines in a receptacle and run the steering wheel back and forth to drain the system. Some have recommended refilling with kerosene and redoing this to clean out the system but I am unsure of exactly how much kerosene I can get back out and such. There aren't that many posts on the proper way to do it so I am still researching.

Thanks again for your assistance

 

[greg_g]

Well, clean and flush the PS system and change the filter before refilling with the fluid of your choice. AW32 may work for you, it may not. As I said, I had one Chinese tractor with hard steering that didn't give me normal response until I went all the way up to 50w fluid. And when I say flush, I mean a clmplete flush. That has to include the lines, the cylinder, and the steering motor. Best way to do that is to drain the system, then refill it with kerosene. Work the steering with kerosene in the reservoir, topping up as it's pumped through. Depending upon how dirty it gets, you might have to drain and flush again with fresh kerosene. When you're satisfied, drain the kero and replace with the power steering fluid of your choice.

//greg//

 

[Wa11banger]

Ok news and update.. I think I need to post a how to just to help people like me (limited hydraulics experience) on the very easy way to replace and clean the steering hydraulic fluid all at once on systems like mine.

I got frustrated with the lack of how-to's on hydralics and just sat there and studied the system. I noticed I only had one line per cylinder unlike the cylinders on my FEL. That made me think it was always positive pressure depending on which cylinder it was "pushing" to change the direction of the wheels. So I jacked up the front end with the FEL, turned the wheels to the left and put a 5 gal bucket under the pressure line. Took the line loose, started the tractor and started turning the wheel to the right. It did just what I thought it would, the wheels wouldn't turn but it pumped fluid out of that line like no tomorrow! So I kept filling and turning until it ran clear. I then reattached the left line, turned the wheels the other way, and repeated the process on the right cylinder. Whalla!! all clean AW32 in the whole steering system except for the miniscule amount left in each colapsed cylinder, and it is much better! Not great but better.

I cycled the steering left and right 10 or so times before putting it back on the ground and I can now steer while sitting stationary except it still wont go stop to stop until rolling. I might drain and try again with AW46 and see if it improves more or gets worse. Oh and I think I feel it "groaning"a little to like a car power steering pump does when its low on fluid. The fluid is at proper level and it is very slight to none, I cant hear it just slightly feel it maybe.

Thanks everyone for your help and inputs.