Brakes still grinding after replacing pads and rotors
A few weeks ago I was driving on the fway and a piece of wood flew out of a truck ahead of me. I couldn't swerve and hit it with my left front tire only. It made a momentary scrape sound and then sounded normal.
A few days later, my front left brake started grinding whenever the brakes were applied at low speeds and got progressively worse in less then a day.
The next day I took it to a brake shop and had the front brake pads and rotors replaced. It was fine for 3 or 4 days, but then started to slowly make a grinding noise again. I took it back to the shop, where they claimed that my back brakes were extremely dirty and that that was what was causing the noise.
Obviously I thought they were full of it but was hoping they fixed whatever they hadn't done before and just didn't want to admit it. Nope still grinding.
A couple days later my boyfriend took it back and spoke with the manager. He claimed that the back brakes were worn out and needed to be replaced. BF bought into this after calling a different shop and they agreed that sometimes noises from the back can sound like there coming from the front.
This of course sounded insane to me but because I'm a girl I don't know anything and obviously the men know what they are talking about. BF took the car to the second shop and had the back brakes replaced. (Fine, since we've had the car for 30k, and haven't changed them, they probably were towards the end of there life anyway).
Naturally this didn't fix the grinding sound (surprise surprise) and it's getting worse by the day. Took it to the original shop today and the manager offered to warranty the parts if I came in the next day. I explained that I didn't think the root of the problem was the pad or rotor and he in no uncertain terms told me that that's the only thing it could be. Which clearly means if I take it back, he won't look for the actual problem.
To be clear, I have explained to both shops more then once about the piece of wood on the fway and that prior to the tire striking the wood, there was zero noise coming from the brakes, front or back.
Does anyone have any suggestions as to what could have been damaged that would cause this problem? The second shop inspected the front left caliper upon my request and said it was fine. I'm at the point that I have little patience for anymore of a run around with these shops.