4x4 on highway

[rsmarr1982]

my 72 k20 is the first solid axle 4x4 ive owned . on the highway im comfortable driving 55-60 any faster and the truck seems a little bit unstable going over bumps in the road or around curves. it doesnt have a sway bar (i assume 67-72 4x4s didnt have them from factory) and i dont have a steering stabilizer on it. tie rods are tight , draglink is new. all the steering seems tight , no play in ball joints. anyone else feel the same about their truck. would a steering stabilizer help?

[Stocker]

Lifted & oversized tires, a SS might help. Stock or near stock, not so much. If everything is tight with no play or slop, you should be good. But you didn't mention alignment and that could be the culprit. Oh btw, my '72 K20 didn't come with a sway bar. Or a SS, though I have run with one and without one. Little or no discernible difference.

[rsmarr1982]

Originally Posted by Stocker

Lifted & oversized tires, a SS might help. Stock or near stock, not so much. If everything is tight with no play or slop, you should be good. But you didn't mention alignment and that could be the culprit. Oh btw, my '72 K20 didn't come with a sway bar. Or a SS, though I have run with one and without one. Little or no discernible difference.

havnt had alignment checked maybe thats a good start

[DarkFlounder]

I daily drive my 72 K2500 on SF Bay freeways. Most freeways, I'm good at 70. Some of the real bad concrete ones, I have to take it down to 65.

4" lift, 35" tires, SS but it's old and probably worn out.

Adding some weight to the bed might help with the stability over bumps.

[cleszkie]

Sounds like either very mild bump steer, caster out of adjustment, or both. I run a solid axle dana 60, 2 inch lift, 35 inch tires, without a swaybar and I can cruise 80 mph with the Blazer tracking perfectly. A good set of pressurized shocks will also help with minimizing body roll in the turns, along with a set of load assist air bags in the rear (which I also run). I've had good results from the Bilstein 5100 shocks on all corners with Air Lift load assist bags in the rear.

[i82much]

I have a 2.5 inch lift and 32's on a longbed K10 and I feel pretty stable at 75 or so, as long as the turns aren't too sharp and the road isn't bumpy. Honestly don't even know whether I have a sway bar or a steering stabilizer, but now that I've read this thread I guess I will have a look.

[57taskforce]

73-87 front sway bar can be added from a donor truck. It's not completely necessary but will make a difference with body roll. All points above are valid. I'd add a stabilizer for sure. If everything is tight up front I'd also suspect alignment issues. 70+ should be no issue if everything is in order.

[rsmarr1982]

I think I might have a alignment problem. I kinda wanna say at time it feels like steering might be fighting itself if that makes sense. With 4.10 gears and stock tires I'm not looking for to high of speed just a little more comfortable when I'm at 60-65.

[Stocker]

Unless something is worn out or modified, I believe caster & camber are pretty much set on a straight-axle truck. If I am mistaken about that, it will be pointed out.

That said, setting the toe-in is relatively straightforward and should comprise the main part of your truck's alignment.

[67swb72klb]

Originally Posted by Stocker

Unless something is worn out or modified, I believe caster & camber are pretty much set on a straight-axle truck. If I am mistaken about that, it will be pointed out.

That said, setting the toe-in is relatively straightforward and should comprise the main part of your truck's alignment.

X2 I set the toe in 1/16 on mine..

[1972RedNeck]

Originally Posted by Stocker

Unless something is worn out or modified, I believe caster & camber are pretty much set on a straight-axle truck. If I am mistaken about that, it will be pointed out.

It is adjustable with the use of shims, but shouldn't be needed.

[SS Tim]

Verify your spring and shackle bushings are all good.
Check for cracked or broken leafs.

Also many trucks have lift springs of some sort. This changes the dynamics of the front suspension beyond the expected rate increase and roll center change.
The original front springs were negative arch. As such, when deflected, they actually shorten the distance between the center pin and the fixed front spring eye. In turn this pulls the axle forward into the bump giving some effective additional toe in when you hit something like a chuck hole.
Positive arch lift springs on the other hand lengthen the distance between the center pin and the fixed forward spring eye. In turn this pushes (allows) the axle to move backward giving effective toe out, thus a pull to that side in the same chuck hole scenario.

When you make changes like this factory alignment settings go out the window. Lifts, especially when combined with wider tires and offsets, often need more toe in and additional caster.

[special-K]

What bumpy curvy roads do you drive over 60 on? That sounds too fast for anything. I've driven all over this country in jacked up big tire (bias ply) 4wds and never experienced what you describe on the hiway. I only drive over 60 on hiways and good roads, favorable conditions.

I see stabilizer bars on solid beam/leaf spring axles as a gimmick. I've put them on the rear, front, driven ones that came with and ones without, and on my current '72 there had been one installed that I removed, and I don't notice any difference either way. Solid front axle trucks corner flat as a Porche. I don't feel much pitch and roll at all in these 4wds. I guess there is some, but I sure don't feel it.

Either something is broken, worn out, loose, or you are finding out the difference between newer stuff and older stuff. I would check the frame at the steering box, the tightness of those mounting bolts, play at sector shaft/pitman arm, shackle bushings, and every nut and bolt involved in the steering and suspension.

[rsmarr1982]

Originally Posted by special-K

What bumpy curvy roads do you drive over 60 on? That sounds too fast for anything. I've driven all over this country in jacked up big tire (bias ply) 4wds and never experienced what you describe on the hiway. I only drive over 60 on hiways and good roads, favorable conditions.

I see stabilizer bars on solid beam/leaf spring axles as a gimmick. I've put them on the rear, front, driven ones that came with and ones without, and on my current '72 there had been one installed that I removed, and I don't notice any difference either way. Solid front axle trucks corner flat as a Porche. I don't feel much pitch and roll at all in these 4wds. I guess there is some, but I sure don't feel it.

Either something is broken, worn out, loose, or you are finding out the difference between newer stuff and older stuff. I would check the frame at the steering box, the tightness of those mounting bolts, play at sector shaft/pitman arm, shackle bushings, and every nut and bolt involved in the steering and suspension.

ohio roads are full of holes and especially bad transitions on and off bridges . speed limits in cities are usually 55-60 and 65-70 once out of a major city and in rush hour you get passed like crazy doin the speed limit.

[swamp rat]

I have had my K20 up to 75 on the freeway many times without issue and that was before i rebuilt the front end, i'd think its just worn out, and yea i'd add that stabilizer, mine always had one on it when it was stock higth as well as lifted.

[Bigdav160]

GM used that same suspension (Suburban/Blazer) through 1991. Set up properly, there shouldn't be any issues on the highway

[jeffahart]

Originally Posted by rsmarr1982

All the steering seems tight , no play in ball joints.

And there you have it. I promise you this. A truck that drives like a dream... After you replace: Ball Joints, Steering Gear, Body Mounts, New Springs in front, and add steering stabilizer, new tires and alignment. You have an old truck with worn out parts. Only thing I have left to do on my truck is body mounts. But it drove like crap until I put in new steering gear(redhead) and king pin front axle(new ball joints would have sufficed if I had kept the old axle). I can now take my had off the wheel on the freeway at 60mph and the truck will still track straight, even over minor bumpiness.

Point is it's likely a combination of issues, you are not correct in thinking all is tight, assume nothing! When all is tight... you will be in bliss with a big happy smile