Around 4-6 months ago I had my front brakes replaced by my mechanic. After he had completed this job I was having trouble with my e-brake not setting strong enough and therefore not working properly. He said no problem I just need to readjust the brakes I installed for you. I had him do so and all was fine for a little while. However, after a couple months or so the car begin to shake under the pedal and in the steering wheel when the brakes were applied. This became worse over time particularly when going downhill. When I contacted my mechanic about this he said that he needed to readjust the front brakes and that he was so sorry he must have adjusted them a little bit wrong and he would have them resurfaced because they are warped now and that was his fault therefore he would pay for the resurfacing and I would not be charged for anything. My question is is this entirely true? I have since been told by other mechanics that the brakes are self adjusting after replacement. Just trying to see if I need a new mechanic. Thank you all in advance!
Front brakes cannot be adjusted. Rear drum brakes may need to be adjusted manually after a replacement, however during normal use they are indeed self-adjusting.
The shaking you are experiencing is very likely indeed to be related to your front brake rotors being warped. While misadjusted rear brakes may have caused some of that problem, that particular cause is unlikely after the rear brakes were adjusted.
The front brake rotors may become warped due to coninuous heavy braking, braking hard and immediate rapid cooling (such as driving into a puddle of water), or just being made out of cheaper grade steel.