The brake that was making all that noise!
I’ve been doing a lot of brakes lately. A couple of weeks ago, I noticed that the Envoy’s brakes were making a little bit of a grinding noise. Other than the noise, they seemed to be working ok so I decided I was going to wait till the scheduled maintenance interval to roll around which would have been at 120k. Then my wife got into an accident, and I was momentarily horrified that the brakes were the cause. Fortunately they were not, but this put a rush on the brake job.
While the truck was in for repairs, I ordered up a set of Power Stop Brake Rotors and Pads, front and rear, to be put on the truck. The weekend after we got the truck back, I went to work. This is what was done.
I started at the passenger side rear wheel because I was also planning on pushing out the old brake fluid and replacing it with new fluid. Starting at the farthest caliper away from the master cylinder is standard practice when bleeding brakes. So the sequence for brake bleeding is: Passenger Rear, Drivers Rear, Passenger Front, Drivers Front.
This job could not have gone smoother if I tried, it could be that I have more experience doing brakes now, or that the design of the GM product allows for easy repairs, but the replacement of the brakes was pretty easy. I started by removing the wheel center piece by using the lug wrench supplied with the vehicle, you just stick it in the whole and twist a little and the center piece pops right out.
I then jacked up the rear of the truck using a known good spot on the frame rail. Any spot on the frame rail would do, but I like to use the trailing arm bracket. This is welded to the frame rail and allows the jack that I use to be kind of snug around the bracket. I usually jack the truck up a little to transfer some of the vehicles weight to the jack. I then loosen the lug nuts for the wheel while the tire is still on the ground. This keeps the wheel from moving while you break the lugs. I then jack up the truck the rest of the way and remove the wheel.
The Calipers were removed from the brake pad carriers using a 14mm socket and a 17mm open ended wrench. The socket goes on the caliper slide pin bolt and the open ended wrench is used to hold the other end of the slide pin and keep it from turning as you undo the 14mm.
18MM Brake Carrier Bolts on the back side of the rotor
In order to get the rotor off, you also need to remove the brake pad carriage. This is removed with an 18mm socket. There are two bolts that hold the bracket on and they are easily accessible and fairly easy to remove. I used to remove these first and take apart the entire unit as a whole, caliper and all, but I found doing it this way was easier during reassembly with the brake pads going in much easier.
Little lock screw that holds the rotor in place
Now for the removal of the rotor! I was really wondering how I was going to get the rotors off of this truck. It appeared to me, after rotating tires and changing brake pads in the past, that the hub was one entire unit. I was wrong! There are two circular brake rotor holders that hold the rotor in place. I used needle nose pliers to pull the tabs out enough that I could grab it with my fingers and rotate to “unscrew” them from the rotor. After removal of the two holders, the rotors slid right off. I didn’t even need to bang on them! A lot easier than the Jetta!
Putting the rotors back on is the exact opposite of the above. Slide the new rotors on, put the circular holders back on, and they are set. Before mounting the brake carriers, you will want to lube the tracks that they slide on with some brake lube. Doing this before mounting keeps the lube off the new rotors. You will then mount the brake pad carriers and put the brake pads in.
Put lube on the areas where the sides of the brake pad touch!
Put some lube on the brake caliper piston and use a C clamp to push the piston back into its bore. Once this is complete, remount the caliper to the brake pad carrier. At this point you will want to bleed the brake.
Push the piston back into its bore
I had my wife push the pedal for me. She was such a big help. I really wanted to swap out the old fluid and replace with new fluid. So I had her pump out the brakes until we had new fluid flowing through the line. This took a little while because we started at the brake caliper farthest from the master cylinder and the brake fluid reservoir needed to be drained.
The procedure for bleeding the brakes is as follows:
- Have helper push down the brake pedal
- Loosen the bleeder screw
- Wait for brake fluid to start slowing it’s flow
- Tighten the bleeder screw
- Have helper release the brake pedal.
- Repeat until there is a steady stream of fluid coming out.
The above procedure will prevent any air from entering the system and results in awesome pedal feel. There was no air in the lines when I started but I wanted to replace the brake fluid so I followed that procedure until the brake fluid that was coming out was no longer black. Keep an eye on the brake fluid reservoir that is mounted on top of the master cylinder. This will get low as you are swapping the brake fluid and you will want to periodically fill it up so that air does not enter the system. I performed a complete brake job on this truck, so I did the same procedure described above on the driver’s side of the vehicle. After bleeding the brakes on that side, it was time to move to the fronts!
Front Jack Point
Of course the first step to doing the front brakes is to jack the vehicle up. I just make sure that the jack is placed securely under the frame rail and remove some of the weight off the wheel that I am working on. I then remove the center cap and loosen the lug bolts. When they are all loose (I just take the initial tightness out of them while the wheel is still touching the ground so that it does not spin) I raise the vehicle up so that I can remove the wheel.
This is a picture of the front passenger rotors still on the car. You can see the groove that has been worn into them by the brake pad that has been completely worn down.
The Brake Pad Was Completely Shot
Using a 13mm socket, unbolt the 2 bolts holding the caliper to the slide pins. You will then be able to lift the caliper off of the brake pads and put it to the side. Be careful not to stretch or damage the brake line. Now take out the brake pads so that you can unbolt the brake pad carrier.
Front Brake Pad Carrier Bolts
Using an 18mm socket, unbolt the two bolts holding the carrier to the spindle. Once this is removed, you will have access to the rotor and be able to use the needle nose pliers as described above to remove the circular brake rotor holders. The front rotors were just like the backs in which the rotors just slid right off after removing the holders.
To put the rotors back on, just slide them over the lugs and return the brake rotor holders to their proper place.
The brake pads that I got had new brake carrier brackets with them. So I removed the old ones by just snapping them off. The new ones just snapped back on over the notch that is there for them. Before mounting the brake carrier, I lubed the new brake pad brackets, again to make sure that none got on the brake rotor. I then bolted up the brake carrier to the spindle, using a little anti-seize compound to prevent the bolts from getting stuck.
Old Brake Pad Brackets
New Brackets installed
Close Up of New Brackets
After bolting up the brake carrier brackets you can then slide the brake pads into position. It was a little difficult to get them into place properly because of the small lip on the new aluminum brackets but with a little persuasion they went on. After the brake pads were installed, I notice how simple and effective the brake design was on the Envoy! The aluminum brackets have a little tab that act like a spring to move the pads away from the rotor when the caliper is not applying pressure. I found myself testing this while admiring the design and it works really well.
The next step is to push the caliper pistons back into the bore. Using some of the brake lube, apply some so the outer casing of the piston bores. This will allow free movement of the piston and hopefully keep the rubber from drying out.
The Envoy has dual piston calipers in the front so pushing them one at a time using the C clamp only results in one of the pistons being pushed out while you are pushing the other one in. Since I am currently not a professional, my solution was to use the old brake pad and push them both into their bores at the same time.
Remount the caliper by sliding it over the brake pads and aligning the slide pins to the proper place. You may need to maneuver the slide pins to get the caliper in the proper position, but it is not difficult to move. Once the caliper is bolted in place, it is once again time to bleed the brakes. Just follow the brake bleeding procedure as described above. Then rinse and repeat for the driver’s side front!
Please leave a comment and let me know how this has helped you.
Thanks for reading!