HOW TO: Replace base brakes with 4 piston Brembos
 

Okay, first off, I am not a mechanic - I did this to my own vehicle at my own risk. If you do it to your own vehicle, you're doing it at your own risk. I'm also not saying that my method is the best, nor that there aren't faster, easier, or more correct per the service manual ways to do this. This is just what I did, doing things as they felt natural.

I got a pair of takeoff 4 pot Brembos and Phastek front stainless lines from a forum member and wanted to upgrade the fronts on my LT as well as flush the factory fluid out. To do the swap I needed:

1/4" drive ratchet with 1/4", 10mm, and 11mm deep well sockets
T-15 and T-30 Torx bits
1/2" ratchet with a 21mm socket
1/2" breaker bar for the socket above or large 21mm wrench (open or closed ended is fine)
1/2" torque wrench rated to at least 150 NM
10mm, 11mm, 13mm, and 16mm wrenches (17mm as well if you're using the Phastek lines)
Flat head screwdriver
A hammer and punch to remove the caliper pins to swap/remove pads
A lug wrench
Blue/removable thread locker
A way to lift the vehicle and more importantly SUPPORT the vehicle

Optionally - vice grips, trim removal tool, gloves, a rubber mallet, and some way to catch dripping brake fluid.

You may notice some of the tools in my pictures don't match these (such as using a 3/8" ratchet and sockets), I just grabbed what I needed as I went through the process, and the list above is the minimum I could cut it down to using one set of tools. Also, apologies for the darker earlier pictures - it was chilly in the morning when I started this and I had the garage closed.

Finally, the correct GM part number for the Brembo rotors is 13511494.

So let's get going: Secure the vehicle - put it on a lift, chock the wheels, engage the parking brake, whatever you can to keep it from moving in your situation - we're going to be under the vehicle and in the wheel well, so check and double check! I engaged the parking brake, chocked both rear wheels, and lifted the front sides one at a time and set them on jack stands.

Remove the lug nuts, remove the wheel, set it aside.



https://i.imgur.com/kk1cXLS.jpg



Optional: I used an 11mm socket to remove the brake line at the caliper and let the line and caliper drain.



https://i.imgur.com/aPMMYyj.jpg



https://i.imgur.com/jp0tn1e.jpg



Using a T-15 Torx bit and driver, remove the 5 screws holding on the cover panel on the back side of the wheel well (3 to the rear of the vehicle, shown, and 2 toward the front, not shown). Using a flathead screwdriver or trim tool, remove the plastic fastener on the lower left side.



https://i.imgur.com/8vhlW51.jpg



Remove the panel and this will expose the brake line connection.



https://i.imgur.com/Jo7suQe.jpg



Using a flathead screwdriver, split the two plastic clips holding the ABS sensor wire to the brake line.
Using a 10mm socket, remove the bolt holding the brake line bracket to the strut.



https://i.imgur.com/QReFhvC.jpg



On the back of the caliper, you can see the two 21mm bolts holding the caliper on. Using your breaker bar/wrench, break them loose. Remove them with the socket and a ratchet.



https://i.imgur.com/w4fGJ0A.jpg



Once the caliper is loose, set it aside and remove the bolts.



https://i.imgur.com/ELvzNrj.jpg



On the left, the factory Brembo bolt, on the right, the factory LT bolt. Both are 21mm heads, the Brembo bolt being very slightly longer and having more unthreaded area at the top. Notice both have remnants of factory red thread locker.



https://i.imgur.com/S1fGBGA.jpg



Once the caliper is removed, use a T-30 Torx bit to remove the rotor retaining screw. Remove the rotor and set it aside.



https://i.imgur.com/QIxOgRc.jpg



Clean the hub. You can see the shield in this picture - it is the same part number with the base LT brakes as with the factory Brembos, so there's no reason to remove/swap it.



https://i.imgur.com/1ciENCs.jpg



Using 13mm and 16mm wrenches, loosen the brake line connection. The large side that is part of the rubber line only has flats on two opposing sides.



https://i.imgur.com/VX1E7AK.jpg



Using vice grips or a flathead screwdriver, remove the clip securing the brake lines to their bracket on the body. Remove the line and set it aside.



https://i.imgur.com/Fm5Kvl0.jpg



Summary picture before reassembly:



https://i.imgur.com/RG2XVzo.jpg



Install the new rotor and secure it with the rotor retaining screw using the T-30 Torx bit.



https://i.imgur.com/H3PSWlq.jpg



It finally got nice out so I opened the garage for better lighting. Install the caliper using the 21mm bolts. I did a test fit, then removed the bolts, applied blue thread locker, and reassembled. Torque spec is 150 NM plus 15-30 degrees, and blue thread locker. If you're doing this without a lift, you may have to be creative to get your torque wrench oriented.



https://i.imgur.com/OjYFUw9.jpg



Route the brake hose up around the ABS sensor line and back toward it's connection point with the hard line. Connect it to the factory hard line, tighten it down, secure it to the bracket with the metal clip, reconnect the hose to the ABS sensor line with the two plastic clips, and secure the 10mm bolt to the strut bracket.



https://i.imgur.com/hBl3pkh.jpg



Reinstall the cover panel on the back of the wheel well using the five T-15 Torx screws and single plastic fastener.



https://i.imgur.com/6g9O3G4.jpg



Remount the wheel/tire and do the other side.


Bleed the brakes using your preferred method - an 11mm wrench fits the Brembo valves and a 10mm for the factory rears and the torque spec I found was 17-20 NM for the bleed valves. I did the two person method with my wife hitting the pedal - I bled the front brakes just to get fluid to them, then did right rear, left rear, right front, left front. I had heard about people having issues bleeding the Brembos - I did the inner valves first, then the outers, and used a rubber mallet to tap the caliper regularly, and had no issues with air trapped in them, though I did find a few bubbles in the factory rears.


Go for a drive and bed the brakes per your manufacturer's instructions. Much nicer pedal feel for me when it was all said and done.


Hope it helps anyone considering the upgrade.

Have you swapped the back as well?

Awesome write up!
Just got my 4 pot brakes. Any chance you have those photos handy? Imgur seems to have taken them down..