[rick1970]

31zook wrote:

rick1970: you sound like you know what your talking about, so a signal from the power steering box to give it the fine control, thats how allot of people do power steering and hydro assist, so it would work for sure, but thats if i want the wheel to follow the front, sometimes ill need it to crab sideways and operate separately to the front, so if i destroy the front somehow i can drive to camp with only the rear there would be a elec toggle switch that i have next to my hand brake and as for as i know the motor would only run when the toggle switch is on. i plan to run 1-2 deep cycle batteries in the tray for this.

If you want the rear to steer from the steering wheel with the front, yes this will work. Fit a switchable solenoid valve that crosses the pilot over that reverses the direction the rear steers compared to the front for crab steer. The pilot signal (or two actually) that you pick up from the steer box (in the same way as hydro assist) is what controls the valve that actuates the rear steer cyl.
For that matter a setup identical to a hydro assist, only fit the cylinder to the rear axle would also work, solenoid valve to change the direction that the cylinder operated in and to shut it off altogether.

That said, i like sound of the setup 3cyl used. Cheap, simple and with a manual lock of some discription you may have a chance of getting it engineered.

[31zook]

3cyl wrote:

Years ago I did the control of the rear steer on the mate's Mogrover using a double throw spring return toggle switch to steer it and a single push button for return to centre. Used 1 inductive prox to tell it when at centre and 1 prox the same to tell it when it was right of centre. No PLC required, just 3 identical 4 pole HC4 12v relays. I must have made it in about 2005 and the Mog has changed hands since then and as far as I know it's still working. Also did 1 for Haultech's front engined buggy and a couple of others. It had an LED pilot light that lit when it was centred as the single ended ram would occasionally creep from valve leakage, easy to operate and cheap to build. Independant manual operation was definitely the go and it would be easy to pin it locked at centre.

that sounds amazingly simple, and the push button centering sounds awesome. any chance of a diagram?

And on the vss front that sounds like it could be an issue, i've no idea how many signals it would be giving (im yet to work that out) but if that is going to be an issue at 30kph, what happens at 110kph, it will probaly get seriously confused

so a speed limiter and 3cyl set up may be the simplest way to go....

[JrZook]

31zook wrote:

3cyl wrote:

Years ago I did the control of the rear steer on the mate's Mogrover using a double throw spring return toggle switch to steer it and a single push button for return to centre. Used 1 inductive prox to tell it when at centre and 1 prox the same to tell it when it was right of centre. No PLC required, just 3 identical 4 pole HC4 12v relays. I must have made it in about 2005 and the Mog has changed hands since then and as far as I know it's still working. Also did 1 for Haultech's front engined buggy and a couple of others. It had an LED pilot light that lit when it was centred as the single ended ram would occasionally creep from valve leakage, easy to operate and cheap to build. Independant manual operation was definitely the go and it would be easy to pin it locked at centre.

that sounds amazingly simple, and the push button centering sounds awesome. any chance of a diagram?

And on the vss front that sounds like it could be an issue, i've no idea how many signals it would be giving (im yet to work that out) but if that is going to be an issue at 30kph, what happens at 110kph, it will probaly get seriously confused

so a speed limiter and 3cyl set up may be the simplest way to go....

That aint hard to work out!

eg;

30kph* (1000/3600) = 8.33m/s

for a 29inch tire one revolution is:

29*0.0254*pi = 2.31m

therefore 8.33/2.31 = 3.59 wheel revs/sec

times by diff ratio: 3.59*3.7=13.3 rev/sec at tail shaft

divide by speedo drive reduction: 13.3/2.85 = 4.67rev/sec

therefore u'll have 4.67*4 = 18.7pulses per sec at the vss or a pulse every 53.5miliseconds

Dan

[31zook]

thanks dan, i did say yet...

thanks all the same

so if i could get the plc to read that i would be all sweet.....or hopefully if 3cyl pipes up again i can run a simple back to basics relay prox switch set up.

[11_evl]

i have full hydro steering with rear steer.
i first set it up on a diverter valve and changer over valve to control rear steer. i had the div to change my hand steering to REAR ONLY. when it was in normal front steer i could switch the change over valve on and have the car crab steer or swich the changeover to the other side and have it tight steer, all thru the steering wheel.. all great in theroy... the prob was the way i had the hydraulics link caused the fluid to go to the easiest ram first, not evenly.
i got rid both valves and just ran the manual spool like everyone else, works a treat

[turbo_deo]

Hey mate are you using an engineer from Newcastle? I'm looking for a decent engineer that is local

Cheers josh

[31zook]

turbo_deo wrote:

Hey mate are you using an engineer from Newcastle? I'm looking for a decent engineer that is local

Cheers josh

im yet to speak to him about this build, but i used athol mullen on my last build.

cut and spun the diff cover, moved the filler plugs around and am yet to tap a barb for the breather.... adding to the tech side of this, i was going to rotate my knuckles 180deg, but after allot of thought i believe a may be able to run the passengers knuckle on the drivers side and vise versa. either that or bolt on the knuckles (upside down and where the 4 bolts are that hold the disk brake holder on mount that up the right way) or just flip the knuckles.... also moved the drian plug to one side so i can shave the bottom of the diff while it's out....

[royce]

you need to do teh knuckles, otherwise your scrub radius, castor, camber will all be screwed up

[31zook]

i had thought of that, but if it's only on the rear and only for slow speed then i guessed it might be right.... ill buy some king pin's and see how it all looks

[royce]

youll at least need camber for engineering

[31zook]

hmm,. didn't think of that.... ok, ill flip the knuckles.

[jake_]

if your still trying to figure out a speed cut-out this chip probably does what you want:
LM2907N

http://au.element14.com/national-semico ... dp/9487778

[jake_]

or the jaycar kit
http://www.jaycar.com.au/productView.as ... rm=KEYWORD

[31zook]

the first chip you posted looks like i would have to know something

thanks, ill have a sqwiz at the jaycar thing

[appsie]

are you planning on a normal double acting cylinder josh or a through rod cylinder picking up both sides?

i think trying to muck around with prox sensors to show centre position and also control lock to lock would be fairly simple and one of the better options.Or manual stops as said before above or could muck around with stop tubes in the cylinder to control length of stroke etc.
Basically you want it to be simple if you go ahead with it and as reliable as possible.Have a look in i think 2 issues ago of 4wdextreme mag at the defender ute on there with rear steer engineered in NSW and in the article it explained him having to have a manual lockout that he unbolted before driving on the trails.I think this is going to be your only option,hydro isnt really liked onroad as it is.

it all seems fairly interesting and cool i say but you mention wanting it to be capable on the rocks with big boys,how capable do you really think it will be on 29s?
KEEP PICS COMING

[31zook]

haha, my point exactly, i have driven on 33x14.5 boggers, 33x12.5 claws, 31x10.5 wranglers, 275 75 R15 bighorns and a range of other HT's that i tried in the bush. from tyre size, i see very little difference in how the car drove, tread pattern and composition is where they shine or die...

I'd think that my 29s, lwb and welded front are twice as capable as swb 33s and rear locka (both have gearing to suit).

Im just keen to see how a well set up truck (not that im calling mine a bench mark, it's just a term im using to describe where im trying to head) can do more then wank factor right on the guy with 35's and a turbo..... im not having a go at anyone with that setup btw, it's just what came into my head....

i also have that issue that kinda made me think about this idea a bit more seriously.... man thats a sweet ride

anyway, yep, just a horizontal double action ram, and a 12v hydro pack. im going to be running high steer (if it ever gets here) so ill have both knuckle tie rod attachment points free, one for the ram and one for the mechanical lock out....

[atari4x4]

can you put 30's on it for me...

i've currently go my brother living with me & among a few thing he is a hydraulic engineer. i'll try & get him to sit down & read this thread sometime during the week & see if he's got any suggestions on set ups & controlling it.

[31zook]

cheers gus

[31zook]

as sorting out my injection is more of a pressing issue then this it's a if i have time job, so things are slow, but trying to be thought out.

my high steer came on Wednesday, i think it's SR, i think it's a heap of un-thought, un-planned heap of crap to be honest you need to grind away at the arm that the tie rod bolts to get the brake bolts in and the holes aint even round????? also, to take the kingpins out you need to undo the four, 14mm bolts behind the disks because there isn't enough room to put the bolt in straight.... grrr

anyway, enough whingeing, i bought a 3" pipe cutter, man it's big, and sliced off the ends of my axles then flipped em, set my pinion angle and set them to zero. mock up of it together.




just need to order my chromo's, pump pack, and ram and we are away, ill be coiling it so ill be taking the body off, will be a while yet

[Brett]

just been reading this. did you widen the diff housing?