Defining the word "easy" when it comes to replacing the rotors on your Chevy Trailblazer depends on your level of mechanical skill and tool inventory. If you have the skill to remove and replace mechanical components while paying attention to detail, then replacing the rotors is quite doable. If you've never raised a wrench in your life or performed a basic oil change, you might find that you're in over your head.
Two-Wheel-Drive Trailblazers
Whenever performing disc brake repairs, always remove 1/3 of the brake fluid from the master cylinder using a brake fluid siphon and replace the master cylinder cap securely.
Two-wheel-drive Trailblazers employ a different procedure than four-wheel-drive models. Once the Trailblazer is lifted and the tires removed, the calipers will need to be removed. If you're not replacing the pads, although it's recommended you do, you can remove the entire caliper assembly by taking off the caliper mounting bolts located on the backing plate of the rotor. Remove the caliper by compressing the piston as much as you can with a large pry bar or screwdriver. Remove the caliper and support it to the suspension with a length of mechanics wire or a bungee cord. Do not allow the caliper to dangle from the brake hose or you can damage it.
Next, remove the grease cap from the center of the hub, remove the cotter pin, castle cap and then the spindle nut and washer. Pry the rotor and hub off of the spindle holding the outer bearing intact. Remove the outer bearing and then flip the rotor and hub face down. Remove the grease seal, which will undoubtedly get damaged, so be ready to replace it. To extract the inner bearing, a brass bearing punch and hammer or a hydraulic press will be require. Many parts stores will perform this for you for a nominal fee if you've purchased the rotors from them.
Replace the rotor and hub back onto the spindle, but attach the caliper first before replacing the washer and spindle nut. Tighten the caliper assembly nuts first and then replace the washer and spindle nut. Tighten the nut and then spin the rotor around a couple of revolutions to seat the bearing. Back off the spindle nut 1/4 turn and align the castle cap onto the nut so the hole in the spindle allows replacement of the cotter pin.
Four-Wheel Drive Trailblazers
The four-wheel-drive Trailblazers employ what is coined as a "knock-off" rotor. Remove the calipers in the same fashion as the two-wheel drive. Next, remove any rotor retaining rings on the lug studs. You don't need to replace these.
Geographical regions will determine the level of ease and what happens next. If the rotor comes off easily, great. However, rust and corrosion often seize the rotor to the hub. Since you're replacing the rotor, you don't have to be delicate to remove it. But you should be cautious of damaging the hub. Strike the flat plate of the rotor with a big hammer. If it's stubborn, rotate it a quarter turn every four to five hammer blows until it breaks free from the hub. Since rust will be flying around from hammer strikes, it's advisable to wear safety glasses.
Clean the hub and remove the rust prevention coating on the new rotor with a parts cleaner or a brake clean spray. Reverse the remainder of the procedure to reinstall.
What to Do After You're Finished
Once the brakes have been replaced, the Trailblazer is lowered, and the front wheels are torqued properly. Pump the brake pedal several times to seat the pads to the new rotors. This will also decompress the caliper pistons to their original position. Last, recheck and adjust the brake fluid in the master cylinder and then test drive the Trailblazer.
