Hey all, I've been trying to diagnose a front wheel shaking that been going on with my 4x4 Blazer for about 18 months now.

When it first started, I thought it was a wheel balance issue. I took it to Pepboys where I bought the tires to have them re-balance it, but they said the balance is fine.
The techs at Pepboys then showed me that the tires had begun to cup on all 4 around the inside treads of the Cooper Adventurer A/T tires I had at that time. They explained to be that the cupping was caused by bad shocks, and that the cupping is causing the shaking/wobbling/oscillation when driving at or above 55 MPH.

Taking their diagnosis to heart, I then began planning for new shocks and tires over the next few months. I bought new Bilstein HD shocks (the old OEM Bilstein's definitely were worn out), and after that I replaced the Cooper Adventurer A/T tires that were severely cupped with a new set of Cooper Evolution H/T tires. I opted for highway efficiency this time around since that is all the driving I ever do.

After test driving the new tires, the shaking/wobbling was still happening. My father, who had worked on older Chevy's most of his life, says it's the ball joints that are causing the shaking at higher speeds. So we began planning to rebuild the whole front end. Ball joints, bushings, and tie rods were all replaced. Spent about 2 weeks on this and finished today. We also packed the front CV axles with fresh grease while we had everything apart. I was fianlly able to take it over to Pepboys to get a proper alignment done and I gave it a proper test drive.

20 miles later at 70 MPH, the shaking is still happening. So now I'm at a lost to what could be causing the problem. Any thoughts?

Here's all the work I've done so far.

• New brake rotors and pads about 18 months ago
• Wheel hubs/bearings replaced about a year ago
• New shocks installed about 3 months ago
• New tires installed about 3 months ago
• New ball joints, bushings, tie rods installed about 1 day ago

Could CV axles be out of balance? I don't how to check that.

I also have concerns about the wheel hubs too. Is it possible that these can go out of balance?
These hubs are from Detroit Axle, and I've expressed in an earlier thread about how bad their quality control is when I bought their front end suspension kit.
I'm worried these might be worn out too because of how cheap they are. But even for cheap ones, they don't wear out that fast, do they? I've only had them for about a year.

I'm going back to Pepboys to have them check the wheel balance again. I didn't see any weights that popped off, but I don't know what else can cause this behaviour.
The wobbling is definitely something that feels like the wheels are out of wack somehow.

 

You should be able to test the hubs yourself to see if they are loose.

You didn't list the idler arm or pitman arm as parts you replaced. The OE spec idler arms are nortorious for wearing out so that the center link can move up and down which allows for some steering free-play for the front tires, in particular on the right side. If you do replace the idler arm, use a Moog or Proforged one as they have a more durable design. I've only ever rarely heard of the pitman arms needing to be replaced.

Did you replace both ends of each tie-rod?

Probably less likely, but have you checked your steering gear and rag joint?

 

Idler arm is what I would look at next if you haven't. And I would check the hubs, as cheap ones dont usually last.

 

Switch fronts with rears - same sides as a diagnostic

 

I did. They seem to spin okay.

Yes.

No. I'm not sure what those are.

I'll look into these next.

 

What about the center link? Would it cause this behavour too? I was browsing parts on Rock Auto and notice this part has greasable fittings too.

 

I looked at some quick videos on these parts. Would these parts only be related to steering sloppiness and handling?
My problem isn't steering wheel wobble or shakiness. Yes I feel a noticeable vibration in the steering wheel, but that's because the whole vehicle is vibrating/wobbling/oscillating/shaking.

 

When it comes to diagnosing vibrations and wobbles, it is hard to do via the web as one person's wobble is another person's vibration. But you say the whole vehicle is oscillating?? That is weird and definitely should not be happening. It sounds like some sort of resonate phenomena, like with an unbalanced wheel, but more. Did you have the rear wheels balanced too?

Did you figure out what a rag joint is? I should have used a better name. It is the joint between the steering wheel shaft and the steering gear.

As for checking those other parts, I would say you might as well.

You said the center link has greasable fittings? I would think those fittings would only be on the things that are attached to it; e.g. the idler arm.

 

What wheels (rims) are on that Blazer? OEM ones? Or some aftermarket?
Are the wheels running true? (lateral and vertical, when checking on the rims)

 

What Christine said. Post a picture of the cupping but idler arm had been a Chevy wear item for decades.

George