98 sunfire brakes

My 98 Sunfire has a grab and release feel when applying brakes. Mechanic fixed this same problem March 2012. I was told it was warped rotors and brake pads. This worked great until four weeks ago when it started again. I find it hard to believe that rotors and pads would warp again after 7 months.
Also the front brakes lock up real easy on wet surface such as a light rain. When they lock up I get a bad rattle sound under the dash. ABS light does not come on and never has. This happens all the time. Even after new pads and rotors were installed. Thanks for any help.

Are you sure it’s not actually the rear brakes locking up?
I believe you have rear drums and if they’re out-of-round or if the linings are contaminated, they’ll lock up when you apply the brake pedal.
If the front is indeed the problem, have your mechanic check runout on the rotors AND the hubs.
Based on the age of your car, it should be time for a brake fluid flush, if it hasn’t been done in the last 2 years.

The rear brake design that’s used on these cars is notorious for lockup issues, so that’s probably where your problem lies. The best way I have found to address this issue is to make sure your drums are not out of round. This means either machining them or replacing them. Also, if you replace them, it’s probably best to machine the new ones before installing them. This should not be required, but I have found many new drums out of round or with a very rough, threaded finish that can cause shudder or shoe clap. Install with new, premium brake shoes and hardware, lubricate the backing plate where the shoes contact it, and properly adjust the shoes once everything is installed. You are looking for very light contact with the shoes on the drum, nothing more. Many people will say the rear brakes are self adjusting and that you have to do nothing, but the self adjusting mechanism is limited in what it can do, so it is imperative that it is given a good “base line” so to speak. It also doesn’t hurt to check the adjustment once or twice a year thereafter. If this is done properly, you should have no further problems, and should have a brake pedal with very little travel that stops the car very confidently, without premature wheel lockup.