Toyota Tundra 2019 - Brake issue

I purchased my Tundra new a 2019.

About a year ago, I was having an issue with the brake making a tinny noise. I worked with the dealer and a few of my friends trying to isolate the problem especially where the noise was coming from.

I changed out the Brakes, Booster (recommended by Dealer, used lubricant on brake parts. No luck arresting the noise.

When there is cold weather the piece, what I think is a piece of sheet metal, stops clamoring. With the warm weather upon us it has started up again.

The difficult part of this whole thing is to get it to make the noise described when I am at the Dealer - I have, and we have, isolated that noise to be on the Drivers side just ahead of the Firewall.

the Service Manager was thinking that it is what is equal to the Master Cylinder - Short of spending another $1,500 to $2,500 dollars, has any one run into this type of issue? I've spent too much on this as it stands today, but it is the only issue I have and knowing how well she runs, I got 327K & 7-yrs out of my last Tundra 2008, one I didn't want to give up.

Any suggestions? Any comment would be greatly appreciated. Thank you!

 

Any way you can post a video with this sound?