Front end problems

Duster 73 said
It's the calipers for sure. Have them rebuilt or trade them in for a pair of rebuilt ones. I would also advise you to have the rotors turned and put on new pads no matter what the current ones look like. That way you will have a good new front brake job. Also remember to lube the slides with a tiny bit of white grease when putting it all back together.

mguner said
If your calipers have phenolic pistons they need to go. They stick and cause what you describe. Get replacements with stainless steel pistons. Flex hoses collapsing internally can also cause a similar problem as mentioned.

That's right, it could be that Phenolic garbage I forgot about that.
Phenolic is basically a plastic and does warp and get scored easily.

So if the OP loosens a bleeder and it doesn't let go it could also be the caliper pistons jamming.
I was under the impression it eventually let go on it's own, and then did it again after a short time of driving again.
I don't think stuck pistons do that. (but maybe)