power steering wont turn on forklift

[zetor3545]

hi guys
sorry about this being a non zetor question but i dont know who else to ask i have just been to see a bonser 90 forklift she is huge! she starts runs but she wont steer she atalls the engine even at full revs! what could it be??? i took the pipes to the steering diverter pack and the feed rings oil through no trouble! i dont know much about steering systems so can you help me

thanks matthew morgan

 

[zetor3545]

surely someone has some idea

 

[dave_peters]

Matthew
You need to systematically check the entire system.
Can you turn the steering wheel and move the wheels with difficulty when the engine is stopped? If it's a normal Danfoss unit you should be able to.
If the pump stalls the engine it says to me that the orbiter may be piped up incorrectly, as there should be a relief valve to protect it. you are lucky the pump hasn' split !, so check that the inlet/ return pipes on the orbiter from the pump and to the tank are not reversed. If that's OK then take the pipes off the ram and see if oil comes out when you turn the steering wheel in either direction. be warned the oil will come out very quickly.
if it does, then make sure that the axle kingpins are not seized up and that nothing mechanical like a track rod isn't bent and jammed and that the ram is free.
If it doesn't then you will have to remove the orbiter and dissassemble it. inside it is really very simple and seals are easily available. Kits for most makes fit the unit. but there is a tool for inserting the shaft seal which while not essential makes it easier to put together. Just carefully note the barrel position in relation to the holes when you take it apart. if you get it wrong the steering wheel will fight back quite violently.If it does move it on one spline. There isnt a lot to go wrong in there and if it isnt leaking then faults are usually stupid : the last one I did had bits of the owners shirt in it which he'd used to replace the filler cap.
Hope this helps a bit
Dave

 

[dave_peters]

.... of course I am assuming its hydrostatic.. if its an older power steering system the you will probably have to replace the unit if the axle is free.
Dave

 

[zetor3545]

thanks for that dave! i went to see it today the weird thing abot it is it doesnt have it own power steering pump? wen the engine is not running the steering wheel feels all notchy and a little when running! wen you turn right on the steering wheel it will turn its wheels around 2 inches and return 2 inches and thats it! i just ran up there now and removed the pipes like you said and oil came out FAST the only thing i can think of is that possibly the seals in the rams have gone and oil has gone past the piston causing the whole issue to just lock up i shall remove the rams and take them apart to see what is going on! i shall keep you informed

 

[Renze]

sounds like an interesting project

 

[zetor3545]

i went over to it on sunday took a friend from college who is doing plant engeneering with me. we went underneath it to try and get the steering rams free the pins are stuck!!! i will be going back ther wednesday with the gas to heat up the pins to release them! seeing that the pins are stuck the kingpins may be too! and now its not drivable because the clutch has stuck aswell