Hydrostatic Steering VS Power Assist

[TBone]

I know this is a dumb question but what are the advantages of hydrostatic steering over regular power assisted steering??

I have had both and can hardly tell the difference when they are both operating properly. On one of my older tractors the hydraulic pump was weak and barely able to lift the 3ph. When the 3ph was up and under load it "starved" the hyrostatic steering to the point it was very hard to steer. This seems to me to be a distinct disadvantage yet all of the manufacturers claim that the hydro is superior.

Can anyone tell me the major differences and advantages/disadvantages of both?

 

[Steve_in_Ont]

I can tell you what the difference is... I struggle with thinking of any operational advantages...

1. Power assisted steering still has a complete mechanical link between the steering wheel and the front tires... It is just hydraulically boosted.

Hydostatic steering has no complete mechanical link, and depends solely on hydraulics for steering control.

2. Advantages... someone might have more info., but I think that the primary advantages are for the manufacturer... With hydrostatic steering there is no need to design and build a tractor around the need for any mechanical link to the front tires... This is potentially a very big advantage in such areas as design flexibility, parts costs, and assemble-ability (three factors that are more important to manufacturers than most people realize.

 

[jinman]

Steve, your premise that the primary advantage to hydrostatic steering is to the manufacturer is probably true, but I guess after having a tractor with a loader which had power assisted steering, I have one question which comes to mind. Why would anyone want to drive a tractor if the hydro/assisted steering wasn't working? It's a lot like pure manual labor to do that. /w3tcompact/icons/tongue.gif I guess if I was out in the middle of the field and my tractor stopped, I might "nurse" it back to the shop/barn if I had power assist steering. That's about the only time I think it would be to the consumer's advantage, and I don't know if that makes it cost-effective to produce and sell. My tractor has a separate hydraulic pump for the steering, so if the main hydraulic pump fails, the hydrostatic steering and hydrostatic transmission both continue to work. I do understand that all tractors are not made this way.
BTW - I have lots of experience with an old Ford 4000 industrial tractor/loader with a faulty/leaky power steering pump. If I hadn't sold it, I'd probably have forearms like Popeye./w3tcompact/icons/shocked.gif/w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif

 

[keeney]

Steve,

Whenever a manufacturer can figure out a less expensive way to make something (assuming they make it work just as good, last just as long, etc), it benefits the consumer as well. Eventually, the competition catches up to the improvement, and then the sales-driven company will start getting aggressive on pricing. They can only lower the price (and stay profitably in business) if they can lower their costs.

- Rick

 

[DVerbarg]

I agree with the other comments about design advantages and not having to work with mechanical linkages as a benefit for hydro steering. Power assisted has one ergonomics advantage that I can think of: consistent position of steering wheel.

When working with rear implements it can be an advantage to know that if a steering wheel spoke is in a certain position that you are going straight. With hydro steering the steering wheel can "slip" and not be centered when going straight. If I had power assist I would have one of those "suicide knobs" installed.

 

[Steve_in_Ont]

Good point on the consistent wheel position... That's something that used to bug me about my TC21D. I got over it, but I never made the connection that it's the result of fully hydraulic stearing.

 

[jinman]

Hey Dave, this weekend, after shutting off my tractor, I tried to turn the steering wheel and found that as I turned the steering wheel, the hydraulic steering cylinder (non-supersteer) was extending and retracting as I turned the wheel (in other words: acting like power-assist instead of hydrostatic). I believe our boomers have a positive displacement of fluid just from turning the wheel. When the engine is running, that fluid is boosted in pressure by the power steering pump. Bear in mind that this is just an educated guess /w3tcompact/icons/clever.gif on my part for now. I haven't checked my repair manual, but I don't see how/why the steering would work this way if this was not the case. Why don't you check it on your tractor too. Try to turn the wheel with the steering off and see what happens. I feel pretty good about this because if I am going down a hill and the engine dies, it's good to know I can still steer the "beast"./w3tcompact/icons/smile.gif

 

[Charliebrn]

Its the same way with my little Bota...

 

[jad114]

hi guys , i have a massey ferguson and has a hydrostatic power steering instead of mechanical linkage like cars . hard to explain , just bought the tractor and there is a leak right under the steering wheel and it is hard to get the tractor to steer unless i keep filling the pump . it is a bad leak , new pump costs $557 and a kit to rebuildit is $250 . it is a killer for a farmer , any ideas? should i buy a new one or rebuild it ? is there any way to to stop the leak , i think the seal on the shaft is busted , don t know , im not a mechanic , need help
norm

 

[jenkinsph]

jad114,
Without any skills in mechanics and no real tools (guessing) you may be better off to hire this done.

I say this because if the steering valve is leaking why would you be pricing the pump.