Strange noise out of nowhere, can't understand why??

[Senpas]

Hello all,
I am writing this topic hoping that someone can help me out.
I have a MB3 from 1997 that is in my family since.
I am now, slowly, trying to bring it back to a newer state. I have the manuals, the tools and the love to work on it and everything was working well until now.
I have changed the front upper arm, front shocks, outer steering, ball joints, all front bushings at lastly cv boots.
Note that the CV boots were changed because they were starting to rip but had no holes.
Now that I have changed everything it started to make a noise while turning the wheel left and right. while stopped and while moving.
It is not the clicking noise that bad outer cv makes as the bearings are bad. It just sounds like a plastic drag sound or a 1 time grind. It is very strange. Almost as when you it a bump whitout shocks.
What can it be? where did I failed or what should I check? I know there is a small loose in the inner steering but just a small one, not even 1 inch, that was already before all the changes I made.
Also I note that the cv axle while in jack stands goes in and out a bit but they are both locked in the transmission and in the wheel. I do not know if it is normal.
Can someone help me? I am just sad as I changed everything and know I have a sound that I had not before.
Thank you all for the support you provide in this forum.
Pedro 
 

[dr_broon]

Hi Pedro. Is it like a groaning sound?b if so it could be the lower ball joints. 

Are you able to get someone to turn the steering while you listen to try and see where the noise is coming from? 

[Senpas]

Hello Simon, 
I  changed the lower ball joints as well.
While on stands, if someone turns the steering I only ear the minor noise from the steering inner arm but the sound only can be heard while driving..
I am out of options, 

[dr_broon]

Sorry, noisy ball joints is the limit of my experience of weird noises (but it's happened so many times to me). Hopefully someone else will have done options to check

[dr_broon]

I was curious, so this is what AI has to say about it:

 

1. Finding the "Plastic Drag / 1-Time Grind" Noise

Since the noise happens when turning the wheel both while stopped and moving, it is directly related to components that pivot when the steering knuckle rotates. Here are the most likely culprits based on what you replaced:

The CV Boot Rubbing (Very Common)

Since you just changed the CV boots, this is the prime suspect for a "plastic drag" sound.

The Issue: New aftermarket CV boots (especially thermoplastic ones, which feel like hard plastic rather than soft rubber) can be slightly stiffer or larger than OEM. When you turn the wheel, the folds of the boot can rub against each other, or the boot can rub against the front shock fork (clevis) or the lower control arm.

How to check: Peek behind the wheel while someone turns the steering wheel. Look closely at the outer and inner boots to see if they are binding or touching the suspension geometry.

Dry Ball Joints or Bushings

You replaced the upper arms, ball joints, and bushings.

The Issue: If any of the new ball joints came without pre-packed grease (or very little grease), they will protest immediately under the weight of the car. Also, if you tightened the bushing bolts while the car was up on jack stands, the rubber is now under massive, incorrect torsional stress when the car sits on its wheels.

How to check: Suspension bushings must always be torqued down only when the car is at its normal ride height (wheels on the ground or ramps). If you torqued them in the air, loosen them up, let the car sit on its weight, shake it a bit, and torque them to specification.

Brake Dust Shield Bent

The Issue: While changing the CV boots, ball joints, and shocks, you have to muscle the steering knuckle around. It is incredibly easy to accidentally bend the thin metal brake dust shield just enough that it lightly contacts the brake rotor or the steering knuckle when the wheel pivots.

How to check: Look behind the brake rotor to see if the metal shield is dangerously close to any moving parts. Push it back by hand if it is.

2. Is the CV Axle In/Out Play Normal?

Short Answer: Yes, absolutely normal.

Do not worry about the horizontal play you are feeling while the car is on jack stands.

Why it happens: As your suspension moves up and down (and when the car is lifted on stands), the distance between the transmission and the wheel hub changes. To accommodate this, the inner CV joint (the plunge joint) is designed to slide in and out like a telescope inside its housing.

What matters: As long as the inner axle is clicked securely into the transmission casing (won't pull out entirely) and the outer axle nut is torqued down tightly to the wheel hub, a little bit of lateral "in and out" play is exactly how the system is engineered to work.

Your Next Steps to Locate the Noise

Because maths and logic are on your side here, you can isolate this systematic error easily:

The Helper Test: With the car safely on the ground, have someone turn the steering wheel left and right while you safely place your hand on the new upper arm, the spring, and near the CV axle (keep clear of moving parts). You will literally feel the vibration of the grind/drag in the component that is causing it.

Check the Inner Steering Play: You mentioned a small amount of play in the inner steering rack. While "not even 1 inch" might feel small at the steering wheel, any physical play inside the steering rack or inner tie rods can alter the alignment geometry under load, causing a binding sound elsewhere. Keep an eye on it, but focus on the rubber/plastic friction areas first.

 

Obviously, treat that with caution as it's from ai, but could be done useful things to check (it's helped me out with a few things now, as well as causing me problems like deleting all my passwords in my Google account 😂)