Using a power beyond steering valve without the PB function?

[BadDecisions]

Ok, I got confused about what was in reference to who, but i see what you meant now about bump steer.. i was already talking in the context that you dont HAVE a drag link anymore (or a track bar)..

But along those lines, have you sort of 'verified' what the side to side play of the front axle is like? As in, maybe strap/chain the axle up to the frame at ride height, jack it up from the frame or winch up to a gantry crane etc, just some way to get the front tires up without the axle holding the truck up, and just push side to side on the axle? I understand the triangulated 4 link should be handling the job now, but it also seems possible that even a good design might still have as much side to side 'play' as a less than perfect track bar, so its at least worth pushing on it to see what it really is. Even the frame end of the arm might be a slight issue. We can weld stuff to a frame and assume that's as good as it gets, but even stock vehicles sometimes crack their steering boxes off their frames and who knows how much it was deflecting in use for how long before that. Just gotta consider all the stuff that could 'give' a little.

Same thing with the steering.. seems you've already got the proper type of steering valve which should resist 'feedback' pretty well, but have you pushed on the wheel to see?

Between all the moving pieces, it could still just be an issue of 'tolerance stackup' just like death wobble often is.

As far as the caster, what happened when you went higher than 7? I've never really run into the downsides of too much caster, just worsening ride quality. I know some stock cars that go 180mph have 9*, but the trail and tire diameter and a whole bunch of other stuff plays into what that actually means between the car and the ground.

Definitely seems like you've done your homework and avoided most of the low hanging fruit problem possibilities. It looks great.

Unrelated but.. at one time i had a stock samurai divorced Tcase and since they have a 1.4:1 high range iirc, for a while i was thinking about using it backwards on something as a divorced .71 overdrive box.. so read into that about my mental state what you will..

Yep, stock Samurai 1.4:1 high range reduction, yet a paltry 2.26 low range reduction. Mine now is a 1.7 hi range, 6.5 low range. Our mental states aren't too far apart...I once spent a while attempting to figure out a way to go to a 1:1 hi range after doing the motor swap, as the freeway RPMs were just nuts with the bigger motor in it, and MPGs barely got into the double digits as a result. But ultimately, I decided to make a dedicated trail toy instead.

Side to side play - none. I've checked that several times over the build time, and yep..familiar with broken steering box mounts. My other toy is a Chevy K5 Blazer squarebody. I'm pretty sure just about all of those squarebodies ended up breaking steering boxes off eventually, lol.

Steering valve resists - yep...kept forgetting about it when I was building, and had a few WTF moments when I went to move the tires over the other direction, and couldn't figure out why I couldn't just push on the tire to move it. Then remembered why

Caster - I didn't feel any difference between 7* and 10*, so I just dialed it back to 7*. Biggest problem any solid axle 4WD rig when lifting them is the pinion angle. Go too far, and the front driveshaft u-joints bind when the suspension droops. Go WAY too far, and it binds at ride height. What a lot of guys end up having to do on big lifts on stock style suspension is cut the inner Cs off, then rotate them back and reweld to get a decent pinion angle and enough caster in there. I have my 4 link set up to minimize pinion angle change, so that I have less than 5* of change from full compression to full droop. Or in other words, as the suspension drops out, the axle rotates to keep the pinion pointed at the t-case output the whole time. I also have the front axle pushed out 14" from stock, and set up ride height to stay relatively low, which helps tremendously in minimizing the driveshaft angle.

Ended up getting called into work today, so I didn't have much time to play with it. Didn't have the steel on hand that I thought I did to make the alignment bars, so I did some quick and dirty tests, by dialing in all the toe-in I could just by collapsing the tie rods as much as I could, and ended up with noticeable toe in just by looking at it. Found the left/right centering of the axle was 3/4" off, and fixed that. Dialed in a noticeable amount of additional caster. Really wasn't looking for specific numbers at this point, just more of a "what happens if I throw a bunch of toe in and more caster as it?".

Result - drove a TON better. It's still wasn't "right", but it's night and day better than it was. Then a little voice in my head said to double check coilover charge pressures at this point. No idea why, but I'm glad it did. Turns out I completely forgot to charge them after installing them...oops. After putting in 200psi of nitrogen, it got better again.

It's still a bit twitchy, but definitely feels a lot more now like it's being induced somehow by how the suspension is reacting to the road surface, and not by my steering input. I was able to comfortably get it up to some decent speeds in the dirt without feeling like I was riding a real fine line with death on the other side, but pavement running is still a bit off, where keeping inside a lane is doable up to about 55mph, but hitting a bump is still unpredictable in how it's going to react. Realistically, I could call it good here, and move on, but now I'm really curious to see just how good I can get it dialed in.

One thing I did notice while testing today is that I can hear what sounds a bit like a whoosing noise in the steering valve when giving it steering input. Especially noticeable if I put just a bit of pressure on the steering wheel one way or the other, but not quite enough to start moving the tires. No idea if this is normal or not?

A panhard bar might give front axle more side to side stability than the wishbone stabilizer.

Would also be an excellent way to break things. The 4 link keeps the tires moving up and down in a straight line through the travel arc. This is inherent in a double triangulated 4 link design. Basically two opposite wishbones stacked. Lower is wide at the axle, narrow at the frame. Upper is narrow at the axle, and wide at the frame. While the tires are obviously going to see some left/right movement through articulation just on the nature of the suspension traveling in an arc, the center of the axle stays centered under the frame during all this.

A panhard bar would be attempting to force the whole axle to move in a left/right arc as well when going up and down, inducing large amounts of binding in the 4 link. Might work OK on something that only sees street miles, but would never work off road. Though there's really no point in even going with a triangulated 4 link if a panhard is also going in, and then it would be much simpler to just build out a parallel 4 link, or a 3 link.

 

[Vigo327]

Nice work on the experimentation and getting some good results!

Glad the caster thing might have helped. Like I said, i know people say too much caster can cause a shimmy, but i've seen 9 degrees on cars that go 180mph so i dont know even think 'too much' can be achieved on stock adjustments on basically any car. Obviously once you have adjustable upper and lower arms you can crank in tons of angle but like you said, pinion angle problems.

I recently did ball joints and a gearbox on a JK wrangler to fix death wobble. The gearbox was the main culprit in my opinion but since I had to do ball joints anyway I put adjustable ones in the lower hole and cranked them to gain some caster without touching the pinion angle. I think if you do adjustable upper and lower you can get maybe 3 whole degrees of caster but an offset ball joint is a smaller ball joint offset in a stock size hole so its a strength compromise, although probably not an issue if you're running 1 ton axles on a buggy to begin with. I have never cut and rewelded an axle tube but maybe i'll have the right project to try it someday. About the mental state again.. I was thinking about cutting and welding axle tube and was thinking how i'd re-center it.. is it dumb that I had the thought to put one of my exhaust pipe expander tools in there to hold it centered up for tack welding?

And that Tcase gearing swap sure sounds good.. I have an 87 Montero with a pathetic low range and it seems like nobody makes anything for the stock box. I put a t case doubler on a Toyota for someone else..that made me jealous too.. I really like the stock trans and have no reason to change it but that crappy low range is a real killjoy.

 

[CalG]

Does the front end hold steering position with both wheels in the air and the steering wheel held from rotation? Engine OFF.

 

[BadDecisions]

Nice work on the experimentation and getting some good results!

About the mental state again.. I was thinking about cutting and welding axle tube and was thinking how i'd re-center it.. is it dumb that I had the thought to put one of my exhaust pipe expander tools in there to hold it centered up for tack welding?

I think there's still plenty of room for improvement, and I also think that a lot of this just comes down to the compromises made with different types of suspension set ups. Such as this particular kind of 4 link setup comes with the benefit of insane amounts of flex or articulation, tons of side to side support, but at the potential cost of stability in the pavement department at speed. After charging the coilovers, the ride height jumped another 2" in the front, so it's starting to look like one of those wannabe prerunner trucks the kids have - jacked up sky high in the front with a saggy rear, lol. The spring rate is just way too high, and I think that's playing into this a bit as well by not allowing the suspension to do it's job properly. So I need to go get myself some lighter spring rate coils first to bring the front end back down, then it will probably just a be a Saturday afternoon's worth of playing with some different toe and caster adjustments again until I find the sweet spot.

As for the tube centering - not at all dumb. We don't all have fully stocked fab shops, and sometimes we get to make do with what we have on hand. Usually, the cut and turn is done not by cutting the tubes themselves, but actually cutting out the weld holding the inner C to the axle tube. But on some of the bigger axles, like the Dana 60 fronts, the tube to inner C and the tube to pumpkin is a VERY tight interference fit. So unless you have access to a very large hydraulic press, such as a 50ton or bigger, they ain't moving. Those axles will just laugh at the 20ton Harbor Freight press most of us have.

So they elect to cut the tube in the middle instead, turn as needed, and sleeve it when rewelding. Before I got my lathe to precisely size sleeves for this kind of stuff, my favorite way to realign tubing was to clamp a length of angle iron with the open side of the V against the tubing, across the cut line. Like this, but I added a couple worm drive hose clamps on either side as well to further secure the tubing from going out of alignment while tacking it up.

View attachment 732687

Does the front end hold steering position with both wheels in the air and the steering wheel held from rotation? Engine OFF.

Enough so that I nearly knocked it off the jackstands the first time I attempted to turn the tires after filling and bleeding the system out, thinking that the new cylinder just had a bit of stick slip to overcome, and I was kicking the sidewalls of the tires to give it enough force to do so. Took a few minutes to remember "oh yeah..non load reaction valve".

I'm actually a little torn on that one. On one hand, one of the biggest reasons I wanted to go to this type of steering was this exact feature - outside forces not allowing the steering to cycle without my input. The manual steering gearbox I was running before offered zero resistance to this, so I was constantly fighting to maintain control of the steering wheel in the rocks, always feeling like I was on the verge of breaking my hands every time the wheel got jerked around. So I like the idea of the non load reaction valve preventing this from happening.

On the other hand, I can see where the load reaction valve can aid in steering stability at speed by allowing the steering geometry to do it's job by keeping the steering centered up, but I don't know just how much force this will allow to be transferred, and I don't want to find myself back in a position of fighting to keep control of the steering again.

After all, I'm building this with off road performance as the primary goal, and if I can make it work on the pavement as well, bonus.