Hydro assist fundamentals

[rockcrawler31]

Man, search on outers sucks dog's danglys

I"m after a bit of basic stuff on hydro assist

First of all, i'm guessing that you want your rams to stop and max out just before your actual knuckle stops so that the rams don't go and try and tear off the knuckles or ball joints right? I.E. at full turn with the ram either fully open one way or the other, there should be tiny gap in between your knuckles and the stops on the housing yes? So that means doing some measuring and getting a ram that has say 1/2 to 1" of travel less than the relay rod has relative to the axle.

My mate has his (75 series on 80 axles) fitted where the old steering dampner used to be. I like this since it's A. out of sight and out of the way of rocks and B. It's easy to package and a shorter run for the hoses.

But i'm wondering if it's better to mount on and behind the axle acting directly rear relay arm instead of the pitman/draglink. The reason i'm thinking this is
1. It's a more parallel to the link that it's connected to so no funny angles and bending moments. And
2. It acts more directly on both knuckles instead of via the drag link first

More importantly, this is all because i snapped a sector shaft at King of the Rim this year and i'm buggered if i want it to happen again. The trail gear site says that their assist kits means that the steering box still takes 60 percent of the load. I want this to be less, so what variables can i change so that the ram takes more load.

Also, I'm more doing this to limit shock loading on the steering box, with a hydro assist does load from say a tire catching a wall or a rock still get transmitted to the steering box? Or does the fluid pressure in the ram (even with no actual steering taking place) absorb and stop shocks?

If i break a pitman arm or sector shaft, if the box is otherwise still working, does that mean that i still have steering via the ram? (albeit at a reduced capacity) This is another reason i'd want it on the tie rod, so that if the pitman arm or the TRE's on the drag link shit themselves, the ram on the tie rods could still work. If i could up the amount of work that the ram is doing, then technically i could have a full hydro system by running a ported steering box with no drag link right?

I have a TC pump from a chev here at home (the old can o' ham reservoir), any idea if it's any good for the job? It was in a truck that had hydroboost braking so it should be up there in the pressure stakes. I could fit that then ditch the old power steering pump altogether.

On that note, if i'm no longer using the toyota pump and there's no fluid in it, i'm guessing it's going to get stuffed since it will still be running off the engine.

[rockcrawler31]

Well i finally found some stuff in here on fitment and porting. But nothing that answers the above questions, so fire away mofos

[91Mav]

G'day mate, I'm waiting on my hydro assist kit to arrive from the the US. I'm obviously not experienced on the matter yet but I'll share what I'm planning.

Just beef up your steering stops or make some sleeves for the ram if the travel is too much for the CV's.

I'm mounting my ram to the axle housing. I think mounting to the Panhard will flog out bushes quickly. The ram will also be more effective and hence put less strain on the steering box if it's mounted parallel to the tie rod. The load will also be shared across 2 tie rod ends instead of one.

Fluid will travel to either the box or ram based on which has the least resistance so a larger ram should take more load off the box but will require more fluid (a bigger or modded pump) to turn as quickly and directly.

The ram will minimise shock loading as the fluid takes time to escape from the ram through the fittings and lines.

I don't think the ram will work if the sector shaft gives up (see the part about fluid travel). If u pulled the input shaft and found a way to stop the piston moving on the worm gear (like welding it), it should work.

The Chev Saginaw pumps are easily modded. Take the high pressure fitting off the back (the 25mm spanner one) and drill out the restrictor to 5-5.5mm. This will increase fluid volume. Behind the high pressure fitting is a pressure bypass. Undo the 11mm bolt on the bottom of it (by holding the body in a vice with soft jaws) and remove the ball, stem then spring. Add a 1-2mm shim/washer under the spring a remove the same amount from the stem then put it back together. This will bump up the fluid pressure.

Hope this helps

[rockcrawler31]

I don't think the ram will work if the sector shaft gives up (see the part about fluid travel). If u pulled the input shaft and found a way to stop the piston moving on the worm gear (like welding it), it should work.

The Chev Saginaw pumps are easily modded. Take the high pressure fitting off the back (the 25mm spanner one) and drill out the restrictor to 5-5.5mm. This will increase fluid volume. Behind the high pressure fitting is a pressure bypass. Undo the 11mm bolt on the bottom of it (by holding the body in a vice with soft jaws) and remove the ball, stem then spring. Add a 1-2mm shim/washer under the spring a remove the same amount from the stem then put it back together. This will bump up the fluid pressure.

Hope this helps

Thanks heaps for that. Like i said, i've got a saginaw pump at home so i just need to make up a mount for it and a wayto tension it where my AC pump used to sit.

When i snapped my sector shaft it was just above the Pitman arm. So the box was still working as it should, and the remainder of the shaft was in there and turning, it just had nothing attached to it to turn

so i reckon in this case, or if i buggered the pitman arm, the stillworking steering box just becomes the orbital valve in a full hydro system right?

[rockcrawler31]

Does anybody have pics of how they've mounted an aftermarket pump to a 1HZZZZZZZZ?

[Z()LTAN]

Man, search on outers sucks dog's danglys

I"m after a bit of basic stuff on hydro assist

First of all, i'm guessing that you want your rams to stop and max out just before your actual knuckle stops so that the rams don't go and try and tear off the knuckles or ball joints right? I.E. at full turn with the ram either fully open one way or the other, there should be tiny gap in between your knuckles and the stops on the housing yes? So that means doing some measuring and getting a ram that has say 1/2 to 1" of travel less than the relay rod has relative to the axle.

My mate has his (75 series on 80 axles) fitted where the old steering dampner used to be. I like this since it's A. out of sight and out of the way of rocks and B. It's easy to package and a shorter run for the hoses.

But i'm wondering if it's better to mount on and behind the axle acting directly rear relay arm instead of the pitman/draglink. The reason i'm thinking this is
1. It's a more parallel to the link that it's connected to so no funny angles and bending moments. And
2. It acts more directly on both knuckles instead of via the drag link first

More importantly, this is all because i snapped a sector shaft at King of the Rim this year and i'm buggered if i want it to happen again. The trail gear site says that their assist kits means that the steering box still takes 60 percent of the load. I want this to be less, so what variables can i change so that the ram takes more load.

Also, I'm more doing this to limit shock loading on the steering box, with a hydro assist does load from say a tire catching a wall or a rock still get transmitted to the steering box? Or does the fluid pressure in the ram (even with no actual steering taking place) absorb and stop shocks?

If i break a pitman arm or sector shaft, if the box is otherwise still working, does that mean that i still have steering via the ram? (albeit at a reduced capacity) This is another reason i'd want it on the tie rod, so that if the pitman arm or the TRE's on the drag link shit themselves, the ram on the tie rods could still work. If i could up the amount of work that the ram is doing, then technically i could have a full hydro system by running a ported steering box with no drag link right?

I have a TC pump from a chev here at home (the old can o' ham reservoir), any idea if it's any good for the job? It was in a truck that had hydroboost braking so it should be up there in the pressure stakes. I could fit that then ditch the old power steering pump altogether.

On that note, if i'm no longer using the toyota pump and there's no fluid in it, i'm guessing it's going to get stuffed since it will still be running off the engine.

Ideally you want the knuckle and ram to stop at the same time, but having the ram bottom out a bit before is ok. Fine turning can be achieved by fitting collars to the ram rod to reduce useable travel.

Mount the ram to the tie rod from diff to rod. Takes all the strain off the steer box.

You want the ram and tierod to be as parallel as possible, if its at an angle to the tierod its going to want to try and roll the rod over the TRE's or Heims.

Pressure spikes (shock loading) in a hydraluic circuit are even and undiminished in all directions, so the steer box will receive the high pressure spike. What it will miss out on though is the physical reaction to the sector shaft and worm nut.

If you snap a pitman arm the hydro assist ram will not move until you bottom out the steering box in either direction. Power steer boxes are assisted in the sense that they only supply 'assistance' pressure if there is a load.

Buy a TC style pump from Locktup and a PSC remote resiviour.

Remove the standard 1HZ steer pump and blank off the port. I did this with mine.

Pictures of the blanking plate and the pump install are somewhere in my build thread.

[rockcrawler31]

Ideally you want the knuckle and ram to stop at the same time, but having the ram bottom out a bit before is ok. Fine turning can be achieved by fitting collars to the ram rod to reduce useable travel.

Mount the ram to the tie rod from diff to rod. Takes all the strain off the steer box.

You want the ram and tierod to be as parallel as possible, if its at an angle to the tierod its going to want to try and roll the rod over the TRE's or Heims.

Pressure spikes (shock loading) in a hydraluic circuit are even and undiminished in all directions, so the steer box will receive the high pressure spike. What it will miss out on though is the physical reaction to the sector shaft and worm nut.

If you snap a pitman arm the hydro assist ram will not move until you bottom out the steering box in either direction. Power steer boxes are assisted in the sense that they only supply 'assistance' pressure if there is a load.

Buy a TC style pump from Locktup and a PSC remote resiviour.

Remove the standard 1HZ steer pump and blank off the port. I did this with mine.

Pictures of the blanking plate and the pump install are somewhere in my build thread.

Fuck yeah, that's what i'm talking about

[Z()LTAN]

Page 22 bud

[evanstaniland]

i have a ported box, single ended ram and cooler that i prob wont need i can double check if you wana purchase

[rockcrawler31]

PM sent brother

[80's_delirious]

Can't help you with hydro assist, but would suggest you run a 105series steering box, it is the same as 80series, but has (supposedly) a thicker sector shaft and different pitman arm.
Can do some measuring for you to confirm it if you want.

[BUSTED100]

Can't help you with hydro assist, but would suggest you run a 105series steering box, it is the same as 80series, but has (supposedly) a thicker sector shaft and different pitman arm.
Can do some measuring for you to confirm it if you want.

yes the sector shaft on the later model 105 series is 2-3mm thicker at the splined end

[Z()LTAN]

I wouldnt worry about that too much, basically what ever fits best.

When you go to drill tap the box please reframe from trying to tap into the veins... Soo pointless. Also use no smaller than -6 jic and 1/4 bsp for flow.

Bit of a plug here but I have a good writeup of a hydro assist setup on my car on the outlaws4x4.com site.

[sprungupcruiser]

Have you got a link for that thread Zolt? I have all the gear together for it now and will be tackling it in the next month or so.

[sprungupcruiser]

don't worry dude, found it. Signing up now.

[Z()LTAN]

http://outlaws4x4.com/?page_id=266/outl ... rs-406070/" onclick="window.open(this.href);return false;

[sprungupcruiser]

good write up dude, really helped with a couple of question i was curious about.

[rockcrawler31]

thanks for the input guys

Zolt why so down on the not tapping into the fluid vein? surely pressure is pressure and tapping into the fluid vein gives clearance away from the internal parts? I"m not being negative by the way i'm just curious.

I can't use an 80 or 105 box as i'm currently using a 75 rear throw box and that would mean re-jigging alla the mounts. The idea of this is to take the load off the box anyway.

I'll have a look at that link

MILO

[horndog]

I have been told that the new v8 cruiser utes have a larger sector than a 75 and they are still a rear throw box.

[Z()LTAN]

thanks for the input guys

Zolt why so down on the not tapping into the fluid vein? surely pressure is pressure and tapping into the fluid vein gives clearance away from the internal parts? I"m not being negative by the way i'm just curious.

I can't use an 80 or 105 box as i'm currently using a 75 rear throw box and that would mean re-jigging alla the mounts. The idea of this is to take the load off the box anyway.

I'll have a look at that link

MILO

The vein is about 3-4mm round, you'll need to be very precise with the drilling and tapping to hit it right. Then you can only use like a 1/8 fitting. Chokes the flow rate and you will find you cant turn as quick as you would like.

The way i did mine had no adverse effect to high speed steering.

When i did mine a year ago i was told by some blokes in the states that the 75s steering box was highly sought after for hydro assist. Something along the lines of internal flow potential. Ive never gone further to confirm this claim though.

[1MadEngineer]

so long as the porting is on either side of the piston seal, it doesn't matter where it picks up from. Pump displacement and pressure is generally most important, and almost any factory pump can be tweaked to match the expensive aftermarket ones.

[THE 109]

What's the difference between the 60,75,80 and 105 series boxs other than sector shaft size?
Do they all have the same internal flow or is the 75 somewhat different?
Do they all have the same mounting pattern?

[Z()LTAN]

They are all pretty different, the 75 differing the most as its rear throw.

Flow wise i wouldn't have a clue.