I think I may have a bad front left wheel bearing. When I go around right-hand corners it seems to be that there is a vibration on the left-hand side. It only vibrates when I turn hard or on rough road surfaces.

I also just replaced the front brakes and rotors and inspected all of my wheel bearings they appeared to be good but I could be wrong!
I just put brand-new 38 inch Toyo MT tires on and I was thinking that with the more tread and I was getting road vibration !? but I had 35 inch toyo MTs before the 38 inch MTs and I did not have this sort of issue.

Also I just had heavy-duty U joints installed about a month and a half ago and was thinking that with these new U joints that could be the problem

One more thing is that I was reading with an aftermarket downpipe on the power stroke diesel sometimes it rubs against the firewall on certain left-hand and right-hand corners causing it to vibrate.
I have no idea where to start and I don't want to just throw parts at it. So if anybody has anything for me to check or look at let me know

 

well, easy to check bearings.

Pull the tire, pull the brake caliper and see if there is play in the rotors.

 

Could be a bad ball joint.

 

Did the problem start after you had the new U joints installed?

I would say this is probably your problem.

How bad really is it? Does your truck bounce up and down badly? Don't think it's your wheel bearings since you said you just had new U joints put in. You said you inspected your wheel bearings. If they were bad you probably would have noticed. Bad U-joints usually pop and your suspension will feel like ****. don't think that's the culprit either.

 

It don't bounce. It just makes a vibration.
Idk if it's the single mass flywheel on my clutch. Or something. And yes the u joints are new. And they're more heavy duty then stock

 

And it's more noticeable when I turn right. Left don't make any noise. Could be my aftermarket down pipe touching the fire wall ??

 

I'd look at the down pipe and balljoints for sure

Down pipe is pretty easy. loosen it up, move it a bit then tighten back down and drive.

 

How do I "properly check my ball joints ! ?"

 

Jack up front end. Pull tire.

Grab the whole assembly and shake.

Is there play?
if yes = bad ball joint,
if no = ball joints good.

You can do it with the tire on, its just harder to tell whats going on, you cannot physically see whats going on.