Today on this mountain bike How To, we are going to be bleeding a set of Sram Code RSC brakes. This same step-by-step process can be followed for any SRAM brakes with their Bleeding Edge technology. So what is Bleeding Edge? SRAM's Bleeding Edge technology is their latest brake bleeding innovation designed to make bleeding SRAM brakes easy and mess free. You can find the Bleeding Edge bleed port on all SRAM Code, Guide, and Level brake models since 2017.
Why do I need to bleed my brakes anyway? Over time, your brakes go through hundreds of hot and cold cycles and as that happens, your brake fluid will start to break down. Just like changing the motor oil in your car every 3 to 5 thousand miles, SRAM recommends you bleed your hydraulic brakes at a minimum once a year and more frequently if you are riding on aggressive trails that require heavy braking. Bleeding your brakes not only replaces the brake fluid throughout the lever, brake line, and caliper, it also ensures there is no air inside the system. Follow along on how to bleed SRAM brakes to keep them working their best!
Here is a list of all the tools we will need to complete this service. If you don't already have your own bleed kit, the SRAM Pro Bleed Kit uses high quality syringes and has all of the supplies you will need. Both the traditional and Pro SRAM bleed kits will come with SRAM's 5.1 DOT fluid, and the appropriate syringes and fittings to get the job done. We also recommend wearing a pair of safety glasses and Nitrile gloves during this service.
For this How To, we will be bleeding the rear brake. You can follow the same process for both the front and rear brakes. Remove the rear wheel from the bike and set it aside. Make sure that no brake fluid comes in contact with either the brake pads or the rotors or they will become contaminated.
First, remove the e-clip with your needle nose pliers. Next use a 2.5mm hex wrench to remove the pad retainer bolt. Pull the brake pads and pad spring up through the top of the caliper and set the pads in a clean space on your work bench. **PRO TIP** - If you aren't going to be replacing your brake pads, make sure to identify which pad was pulled from which side of the brake caliper. That way when you go to put the pads back in the caliper and reinstall the rear wheel and rotor, the pads will be square and centered to the rotor just like before. If you are going to replace your pads, this is the perfect time to do so.
Push the correct bleed block into the caliper. The bleed block will return the pistons fully in to the bores and will keep the pistons from advancing throughout the bleed process. Either of your SRAM bleed kits with come with an assortment of bleed blocks that are designed for the Code, Guide, and Level brakes specifically. If your bleed block calls for it, install the pad retainer bolt through the bleed block and tighten using a 2.5mm hex wrench.
First thread the bleeding edge tool and lever bleed clamp assembly on to both syringes. Fill the lever bleed syringe 3/4 full with SRAM 5.1 DOT fluid. Fill the syringe with the bleeding edge tool with a small amount of DOT fluid (about 1/4 full). For both syringes one at a time, hold the syringe upright and pull all of the fluid from the line in to the syringe. Then cover the tip of the syringe with a rag and push all of the air out of the system. Close both syringe clamps so you don't lose any fluid.
For brakes with contact point adjustment, unwind the dial in the opposite direction of the arrow until it stops. First measure the distance between your lever blade and the grip and then adjust the lever blade until it is 75-80mm from the center of the grip.
Using a T10 Torx wrench, remove the bleed screw from the lever and wipe off any access brake fluid that comes up on to the lever. Thread in the lever bleed syringe while the syringe clamp remains closed.
Remove the bleed plug and then use a 4mm hex wrench to loosen the bleed port 1/4 turn and then gently retighten it. Push the bleeding edge tool and syringe in to the bleed port. You will feel and also hear audible click in to place. Open the bleeding edge syringe clamp and then turn the bleeding edge tool 1 complete rotation to open the system. Do not ever exceed two complete rotations.
Open the lever bleed syringe clamp, hold both syringes vertically, and gently push DOT fluid from the lever down through the brake line and into the bleeding edge tool syringe. Stop before any air enter the hose tube at the lever bleed sysringe. Brake fluid will fill the syringe at the caliper on its own. At this time, do not pull suction at the caliper. Some will refer to this technique as a wash. You are cycling brake fluid from one end of the line to the other allowing you to push out old fluid and any air bubbles in the system.
If the brake fluid coming out of the caliper in to the bleeding edge syringe is discolored, remove both syringes, discard the old brake fluid and return back to step 6. If that is the case, to remove both syringes, first close both syringe clamps. Then close the bleeding edge tool clockwise and remove the caliper syringe first. Next unthread the lever bleed syringe.
Hold both syringes upright and draw suction with the lever bleed syringe. This will draw fluid from the bleeding edge tool syringe through the caliper and brake line up through the brake lever. Stop before any air enter the syringe tube at the caliper. Repeat steps 8 and 10 until only a small amount of bubbles appear. For best results, make sure your brake lever is up higher from the brake caliper so that air has the best chance of rising to the top and out of the system.
Turn the bleeding edge tool clockwise 1 full rotation and until it stops to close the system. Pull the lever blade a few times and let it return normally. Next pull suction on the lever bleed syringe to create a vacuum. Then compress and release the plunger to pressurize the system. Repeat the process until there aren't many air bubbles coming up through the syringe line. One last time, compress and release the plunger to equalize the system. Close the syringe clamp and remove the syringe from the brake lever. Use a T10 torx wrench to reinstall the bleed screw in to the brake lever. Wipe away any excess brake fluid on the brake lever. Using a T10 bit socket and torque wrench, tighten the bleed screw to 1.5-1.7 Nm (13-15 in lbs). This is somewhat option because the torque spec is so low. Tighten the bleed screw snug but not too tight.
Remove the bleeding edge tool syringe without rotating the syringe. Tighten the bleed port using a 4mm hex bit socket and torque wrench to 1.5-1.7 Nm (13-15 in lbs). Again, this torque spec isn't super crucial since it is so low. Snug up the caliper bleed port with a 4mm hex wrench but do not over tighten. Install the bleed plug.
Before installing your brake pads, use a clean towel or rag to remove any brake fluid residue on both the brake lever and caliper.
Using a 2.5mm hex wrench, remove the pad retainer pin and remove the bleed block from the caliper. Remove your gloves so that no brake fluid comes in contact with the brake pads. Install the brake pads in to the caliper and remember which pad was oriented on which side of the caliper originally. Install the pad retainer bolt and torque it to 1-1.2 Nm (9-10 in lbs). Install the e-clip on to the pad retainer bold.
Install the wheel and axle correctly. Before squeezing the brake lever look to see if the brake rotor is centered in the brake caliper. If the caliper is centered, squeeze the brake lever a few times to advance the pistons in the caliper. If the caliper is not centered correctly, loosen the brake caliper bolts and then squeeze the brake lever to advance the pistons. Center the caliper and tighten the caliper bolts. Finally adjust your brake lever blade and contact point adjustments to your liking!
Max Morgan is 26 years old, and lives in Brevard, North Carolina. Max grew up in Atlanta, Georgia and started racing downhill at the age of 15. He has now been racing professionally for the last 9 years, competing in the UCI World Cup series and U.S. Pro GRT series. To learn more about Max, check out Max's rider spotlight here!