Intermittent steering wander?

I’ve been driving my 1983 K5 blazer (5.3/4L60E/NP208, 6” lift, 15x12MT, 35x12.50r15) pretty much everyday, and there’s a weird steering issue I’ve never experienced before. Sometimes it’s driving perfectly fine with little to no wander and other times I’ve having to constantly over correct it back and forth and have a hard time keeping it in one lane. I did not install the lift but I’ve done a pretty decent once over and I haven’t noticed anything wrong. I retorqued all the ubolts and a couple were loose but no improvement. New upper and lower balljoints, tie rod ends, drag link, it has not had a proper alignment but when I did the tie rod ends I never moved the wheel I left it sitting on the ground and adjusted the new to drop right in where the old was. Guy before me daily drove it as a diesel until he snapped the crank and said it didn’t have any issues steering. It has like almost a bump steer but not quite? It’s more like say you’re going down a road and there’s a long patch on the passenger side and the wheel drops slightly for the different height it’ll start pulling that way? But going down a bumpy road the wheel doesn’t jerk all around? The wheel also doesn’t return to center properly someone mentioned that being new balljoints and it’ll wear in?

Ball joints possibly. Mine would do more of a dart, only on very specific road conditions. Fixed that issue after a front end rebuild. Still follows the road a little bit.

I would say most of it is an old truck with 2 solid axles and 4 leaf springs, only amplified by a lift. I daily mine too. I could probably use a fresh steering box, but it likes to follow the road surface sometimes. You really notice it on backroads when the ruts get a little deeper.

If you've never driven a full leaf spring truck with 2 solid axles for any real period of time, it won't feel like any modern pickup past the 90's.

Understandable, yes I’m fairly familiar with these trucks this is the biggest one however, I probably wouldn’t have lifted it but I got a good deal on it. You could probably describe it as a dart, it wouldn’t be as bad if my correction didn’t lead to me just steering back and forth trying to even it back out. There’s one road in my town I honestly try to avoid. It’s a long stretch of straight highway with a drop off on each side with water, the guard rail has dropped lower than the road in one spot and there’s huge cracks because the road is sliding down into the water I guess? That spot is scary scary especially in the early morning when it’s dark and heavy traffic headed to work.
I did have a lot of play with both front wheels, drivers side lower balljoint was wasted and passenger side wheel bearings. Replaced both sides upper and lower with MOOG and all wheels bearings and seals with Timken. It’s tighter for sure, but still the same issue. There’s little to no actual play between the steering wheel and the tire. I’d say ~1/8 turn of the steering wheel and the wheels have already started moving.

Have you checked to see that you get an equal number of turns of the steering wheel turning full lock left to right? If the steering box is not centered when installed it will not have natural centering of the wheels and the steering linkage when you drive straight ahead. It will look fine when driven slowly, but as you loosen your grip a little at highway speed it may try to self-center. Feels like you are always trying to correct it a little.

I don’t believe I’ve checked that, I can but as far as I can tell it’s never been off? I know the steering wheel isn’t perfectly lined up after the drag link replacement but I just haven’t bothered to fix it yet. I don’t have a local alignment shop so I don’t have any numbers on where everything is. Best I can do is strap a 2x4 on each wheel and measure toe.

How much lift do you have? Is the steering arm / pitman arm stock or is it matched to the lift ? If your drag link is not close to level you get bump steer when the suspension moves. The higher the angle the more bump steer.

Supposedly 6” rough country with the include raised knuckle. It’s not level but it’s not super steep either.

Here’s a few pics

The angle doesn't look too bad. I see that you have no sway bar; that could contribute to the wandering.

What's your caster check at?

I would run a ton of caster in that setup - like 10 degrees.

Toe needs to be in - like 1/8".

Straightening the steering wheel is easy. Just adjust the fore/aft drag link until the wheel is where you want it. It does not affect the front end geometry.

K

@Keith Seymore is caster something I can measure at home? With no local alignment places I can’t get a computer number.

Not easy...remove wheel, axle, rotors and knuckles. Run a straight pipe trough the ball joint holes on the axle and measure the angle. Even with this method it's not exact cause angle of the truck and other factors are not known. Best would be to visit an alingment shop.

Agree - best to visit an alignment shop. Without data you are just spitballing.

But - the caster shims do come in known amounts, so you would know how much you are adding.

K

Having a similar issue on my winter Astro. And it sucks, this is the fist time I need a good alignment that I cannot do myself, as every shop I worked in had machines, and I no longer work in a shop. Anyway, first- darting-
Tires/tread
Road conditions
Poor alignment, especially caster and toe.
Loose parts, binding parts
Loose steering box aggravates problems, a steering box control valve can cause this, but is rare
Not uncommon in certain vehicles, FS blazers, jeeps and lifted trucks. Just the play in the rag joint and the sliding shoe on the short shaft can aggravate, even cause such. Which is why lots go to an aftermarket shaft.
Now if you want to know about the newer trucks, and the "death wobble" ask----lol

I had the same/similar issue. Blazer with a 6” lift. Guy before didn’t have it set up, and a 6” lift is way too high for such a short truck (my opinion). It kept loosening bolts on the steering box, and I expected eventually it was just going to crack the frame. I eventually figured out the steering box was flexing the frame as it drove. Solid axle, short wheel base, leaf springs…..all not conducive to stability with a High lift. I got it set up right eventually and boxed the frame around the steering box. Straight as an arrow ever since.