Paulmitchell1984
Well-Known Member
didnt realise they wernt road legal, hmm may re think that idea then lol...wondering if the p38 power steering pump will be upto the challenge
Hydro assist is the only option, or build a full hydro axle case and switch it in/out for comps.
P38 pump is higher pressure yes.
Surely the best way to do it for pure steering angle would be to remove the trailing arm link and the steering arm and simply run on a gearing system thats helped by a hydraulic ram, still got your mechanical link then plus hydro steer.
I may later, only having a break from a uni assignment atm.......need to restart in a bit but I'm procrastinating
The way truck systems work is far better its a hydraulic ram working in conjunction with the standard PAS, the hydraulic ram replaces the steering damper from memory or bolts to the axle and chassis......cant remember without looking and then it runs off the PAS box so when the PAS box is active extra fluid is pushed into the ram which takes a lot of the weight off the gears inside the box and off the arm too but theres obviously still a manual backup system if the ram fails
you can get pas which consists of a ram with a control valve ,moving the steering activates hyd assist but obviously requires manual steering box and drag link ,unlike full power which just uses an orbitrol control valve and a ram with just pipes
Basically it's a double acting hydraulic cylinder ie the chrome rod sticks out of both sides. As it says above forklifts have used it for years. I believe that you can't use full power hydraulic steering on the road in this country unless it's for agriculture like those telehandler forklifts that farmers use. The reason you use it on the road in the UK is that when it fails you hav no steering whatsoever which is fine when you are just crawling around a pay and play site but brown pants time at 60mph on the motorway...plus it makes a mess. That's why you have power assisted steering (PAS) on your car, because when it fails ypu still have a manual rack or box (albeit quite heavy) to get you out of trouble.
This is actually false!
Steering units are actually available with a means to steer manually. This is taken from pirate 4x4.
Steering Unit Integral Valves
If you recall how the steering unit is in fact a combination of valve(s) and metering unit, it will not be a surprise that there are often (depending on manufacturer) a number of "optional" valving functions available on steering units. Most are not really required by us, except for one very important one - the#Manual Steering Check Valve. Most, if not every steering unit I have ever read about that we might possibly use includes one of these. It is a small valve built in to the steering unit that allows the steering unit to act as a small hand operated pump (by turning the steering wheel), providing limited manual steering, should the engine, pump or a belt quit. In my experience, the result is that the steering operates almost identically to normal automotive Saginaw power steering with no power. It is extremely difficult, if not impossible, to manually turn 38" tires at low pressure in a spooled and slugged front axle while sitting still with the engine off. However, with, say, a black YJ belonging to a good friend towing you along at a reasonable clip, it's actually quite steerable. I know this, because the first day I was testing my hydro steering I fried an alternator and a coil!
For anyone considering hydrostatic steering i suggest you get comfortable and take a read of this.
Pirate4x4.Com - Extreme Four Wheel Drive
Normally the engine fails not the hydraulics