Unpredictable Steering

[hootenholler670]

Hey All,

I have a 97 C1500, I am getting a very unstable steering wheel and sometime when i hit a some bump in the road it becomes very unstable and unpredictable, it seems like im all over the road. i have put leveling blocks on the front springs. it was like this before the leveling blocks. I have changed gearbox, shocks, rag joint, inner and outer tie rods, idler arm, pitman arm, and sway bar links. I have had it alignment done. But it needs another.

I have read where some people have said control arm bushings.. I can say my bushings are in pretty bad shape.

 

[Scooterwrench]

Could be too much toe in. That will make it squirrely.
Alignments are only as good as the condition and calibration of their equipment. I went through that with my ElCamino and got the excuse that they didn't have anyone that knew how to align older vehicles. Took it to another shop that said they were re-aligning vehicles from the first shop on a regular basis and the specs were out the same amount on all of them. On mine it was wrong caster.

 

[Schurkey]

97 C1500

I am getting a very unstable steering wheel and sometime when i hit a some bump in the road it becomes very unstable and unpredictable, it seems like im all over the road.

That description makes it sound like loose parts, not a faulty alignment. Toe, in particular, can make for twitchy steering--but the twitchy steering is "full-time", not just after hitting bumps.

i have put leveling blocks on the front springs. it was like this before the leveling blocks.

Did you realign the vehicle after changing the ride-height? Changing ride-height changes camber, caster, and toe.

I have changed gearbox,

Is the "new" gearbox appropriately tight? Is the frame rotted somewhere around the steering box mount?

A few years ago, a buddy of mine had a Ford with steering issues. I found that two of the steering box bolts were loose, one broken.

By the time he got around to doing something about it, the rest of the bolts broke. I got to help him tow it home. It was about one step away from totally uncontrollable. The front tires went whichever direction they wanted, restrained only by the fact that the front of the truck was tow-chained to the truck pulling it.

shocks, rag joint, inner and outer tie rods, idler arm,

Both idler pieces, or just one?

pitman arm, and sway bar links.

How about wheel bearings? Ball joints?

I have had it alignment done. But it needs another.

I have read where some people have said control arm bushings.. I can say my bushings are in pretty bad shape.

Control arm bushings keep the camber, caster, and to some extent toe, stable. They're CRUCIAL for vehicle handling.

As long as we're talking about bushings, how are the leaf spring and shackle bushings? Rear axle U-bolts? Just because the front end steers goofy, doesn't HAVE to mean that the front end is the problem.

 

[1998_K1500_Sub]

Hey All,

I have a 97 C1500, I am getting a very unstable steering wheel

Do you have EVO on that truck? EVO can become funky.

Yeah, I know, "What's 'funky' mean?"

Here's one description:

https://www.gmt400.com/threads/evo-power-steering-assist.35650/post-925679

GM made an "EVO delete" kit as a means of remedying the behavior.

 

[alpinecrick]

Hey All,

I have a 97 C1500, I am getting a very unstable steering wheel and sometime when i hit a some bump in the road it becomes very unstable and unpredictable, it seems like im all over the road. i have put leveling blocks on the front springs. it was like this before the leveling blocks. I have changed gearbox, shocks, rag joint, inner and outer tie rods, idler arm, pitman arm, and sway bar links. I have had it alignment done. But it needs another.

I have read where some people have said control arm bushings.. I can say my bushings are in pretty bad shape.

First, if the steering is that bad the alignment shop should have caught if something was wrong, identified it, and informed you.

Secondy here's a trick about alignment shops: When it coes time to make an appointment tell the person(s) that you want them to drive it when they're done with the alignment. Remind them when you arrive with the truck.

I've been doing this for years now, and MORE than half the time when the guy pulls back into the parking lot he drives my trucks/vans right back onto the alignment rack and goes back to work on it.

I don't say a word, just give them the most sympthetic look I can muster.......

 

[alpinecrick]

That description makes it sound like loose parts, not a faulty alignment. Toe, in particular, can make for twitchy steering--but the twitchy steering is "full-time", not just after hitting bumps.


Did you realign the vehicle after changing the ride-height? Changing ride-height changes camber, caster, and toe.


Is the "new" gearbox appropriately tight? Is the frame rotted somewhere around the steering box mount?

A few years ago, a buddy of mine had a Ford with steering issues. I found that two of the steering box bolts were loose, one broken.

By the time he got around to doing something about it, the rest of the bolts broke. I got to help him tow it home. It was about one step away from totally uncontrollable. The front tires went whichever direction they wanted, restrained only by the fact that the front of the truck was tow-chained to the truck pulling it.


Both idler pieces, or just one?


How about wheel bearings? Ball joints?


Control arm bushings keep the camber, caster, and to some extent toe, stable. They're CRUCIAL for vehicle handling.

As long as we're talking about bushings, how are the leaf spring and shackle bushings? Rear axle U-bolts? Just because the front end steers goofy, doesn't HAVE to mean that the front end is the problem.

This^^^
The idler arm bracket is at least as important as the idler arm, probably more important, but it sounds like more than that.

 

[df2x4]

Do you have EVO on that truck? EVO can become funky.

Yeah, I know, "What's 'funky' mean?"

Here's one description:

https://www.gmt400.com/threads/evo-power-steering-assist.35650/post-925679

GM made an "EVO delete" kit as a means of remedying the behavior.

I had similar experiences with the EVO in both of my '97s. Along with other issues, including the system sticking in full boost at all speeds intermittently. Replacing the sensor on the steering column referenced in that thread seemed to solve it temporarily, but they both got to the point that it was a recurring issue.

EVO is bypassed on both of my trucks now. Red truck with a '96 power steering pump and pressure line, Suburban with the GM EVO bypass kit (part number 19168825). The red truck originally had a GM EVO bypass kit as well, but something behind the pump (I suspect the extra connection point that the GM bypass kit introduces) started leaking badly, so I replaced it with the '96 pump and pressure line. I can't tell any difference between the two EVO bypass methods, and steering feels good all the time in both trucks now.

I'm not 100% sure that EVO is the problem here, but I'd definitely be suspicious of it if it's still operational.

 

[Orpedcrow]

I also vote for EVO. My truck was a real handful till I got rid of it.

But also, as mentioned, check the frame and the steering box.

 

[hootenholler670]

Thanks everyone. i have a list of things to check.

yes it has evo. and its leaking. will bypass that. also at low speeds the wheel can become hard to turn. Does that mean evo ?

i did do the alignment after the level.

will check their work for tightness.

both idler parts have been changed. not the ball joints

i changed wheel bearings not to long ago. will check again. but it was doing that before wheel bearing change.

will double check the gearbox. the frame was in good shape, and i tightend the pi$$ out of them

 

[Caman96]

Sounding more like EVO.