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  1. #1
    Bronze Member Dadsgreenpsd's Avatar
    Join Date
    Jun 2006
    Posts
    59
    Location
    Maine
    Tractor
    Jinma 254, and JCB 1550B

    Default Steering revisited Jinma 254

    Ok, I decided to do some troubleshooting the other day on the steering cylinder. I took it off (side mount) and decided to flush some of the fluid out of the hoses. Promptly drained out the hyd. system, but it did not seem to have much force.

    Anyway, I put the cylinder back on, and hooked up one hose at a time to see how much it bypasses. Imagine my surprise when no fluid bypassed and came out the opposite port. What gives? What do I check next?

    I have almost zero steering to the right now, but pretty good left hand steering. If I hit a rock with one wheel or the other, however, it will head in that direction.

    Any guidance welcomed! Thanks!

  2. #2
    Super Star Member Diamondpilot's Avatar
    Join Date
    Jan 2007
    Posts
    14,524
    Location
    Daleville, IN
    Tractor
    Jinma 254/284 Ford 861 Powermaster at work

    Default Re: Steering revisited Jinma 254

    If you can get a pressure gauge put it between the cylinder and the hose coming out of the steering box mounted at the base of the steering wheel. My guess is your steering box must be the problem or the priority valve. The priority valve is a place to look but does not make since because you have steering in one direction but not the other.

    Chris

  3. #3
    Elite Member RonMar's Avatar
    Join Date
    May 2005
    Posts
    2,760
    Location
    Port Angeles WA
    Tractor
    Jinma 284 delivered 06/28/05

    Default Re: Steering revisited Jinma 254

    Your description of barely having any steering to the right is very telling. That is the pull direction of the steering cylinder and is weaker than the push direction because it has less piston surface area because of the pushrod and therfore less pull force at a given hydraulic pressure. So that tells me you have a pressure issue.

    Ok, so there are 2 valves used in the hydraulic steering system. One is the diverter valve located down by your right toe when seated on the tractor. The other is the steering valve located at the bottom of the steering column.

    The diverter is a demand type valve. When not turning the steering, most all the fluid goes thru the diverter and back to the 3PH control valve. A little trickle is sent to the steering system which pressurizes that line to the steering valve when the wheel is not being turned. This pressure holds the diverter in the position to send the fluid back to the 3PH. As soon as a demand is placed on the steering and fluid is drawn that direction, the diverter piston slides and sends fluid to the steering valve to provide power assist as long as there is a demand(wheel is turned).

    The second valve is the steering valve/pump itself. I use the word pump because it is basically a vane type pump with 2 inlet and 2 outlet ports. As you rotate the wheel, you draw fluid in from 2 of the ports(one connected to diverter, and one connected to a cylinder) and discharge fluid from 2 ports(one connected to a cylinder and the other connected back to the resovoir. When you turn the other way, the flow to the cylinder ports is reversed to push/pull the wheels the other direction, but the inlet from the diverter and outlet to the resovoir remain the same.

    Since it is a pump, it can work independent of the main engine driven pump, so you don't loose steering if the engine quits or the main hydro pump fails. Just like a car with power steering, the steering still functions, it just takes some muscle. With my engine off, it takes about 4-5 complete steering wheel revolutions to get from full left to full right steering. This is easier to check with the wheels off the ground. With mine setting on gravel, it definitely takes 2 hands to pull the wheel thru these 4-5 turns. How does yours work like this?

    Before I did any checking, especially if I had the system open, I would first make sure there is no air in the steering system. To do this lift the front wheels off the ground and rotate the steering repeatedly back and forth from steering stop to stop. If you are getting power assist with the engine running(turns from stop to stop with 2 fingers on the wheel) then the diverter valve is most likley functioning as advertised. Once all the air is purged, set the wheels back on the ground and turn off the engine. Try turning from full right to full left steering with the engine off. If it won't do it, I believe your steering valve is having issues with making pressure to move the cylinder, or using the pressure provided by the main pump via the diverter to move the cylinder. The pressure from the main hydraulic pump is only helping the steering pump to rotate. It is the steering pump at the bottom of the steering column that actually moves the fluid to-from the steering cylinder.
    Ron

  4. #4
    Advertiser
    Platinum Member

    Join Date
    Mar 2004
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    1,346
    Location
    Texas

    Default Re: Steering revisited Jinma 254

    I'm betting on the steering cylinder being the problem,did you rebuild this cylinder,? The side mounts are on the left side of the tractor running with the engine ? the front mounts are in front of the axle ? Some of the old side mounts I cannot get rebuild kits for and you have to replace the cylinder

    Tommy
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