Inject new life into your Avid or SRAM disc brakes with our step-by-step guide,

We show you how to take the blood, sweat and tears out of the Avid and SRAM brake bleed process using the Bleeding Edge adaptor tool.

>>> The best mountain bike disc brakes

Words by Charlie Collins

Need to know

  • Time taken: 30-45mins
  • Difficulty: Moderate
  • Tools needed: SRAM brake bleed kit with bleeding edge tool, DOT 5.1 brake fluid, bleed block, T10 Torx, 2.5mm Allen key, rag, isopropyl alcohol/brake cleaner, nitrile gloves.

Watch the video

Although this video below doesn’t show the Bleeding Edge adaptor tool it does still contains essential need-to-know methodology.

Most new SRAM disc brakes are designed with a specific bleed port in the caliper to be used with a Bleeding Edge tool. The idea is to reduce the amount of fuss and mess when carrying out a successful brake bleed.

By utilising a quick and simple pop on/off bleed-port interface, Bleeding Edge minimises the chance of air sneaking in to the system. It’s simple and incredibly easy to fit and gives a defined snap to tell you it is correctly inserted in place. The Bleeding Edge tool also allows the caliper bleed port to be closed off before the syringe is removed, eliminating oil spillage and reducing clean up.

SRAM brakes that use Bleeding Edge also have an improved oil path through the caliper to further help with the bleeding process – all the compatible models can be found on the SRAM website.

It’s recommended that you wear nitrile gloves when handling DOT brake fluid due to its corrosive properties. It can actually strip paint, so wipe away any spillage as quick as possible! Also ensure you have removed all remnants of brake fluid before fitting the brake pads and wheel back in to position, the smallest amount of oil will contaminate the braking surfaces and is almost impossible to remove.

>>> How to install a disc brake

sram brake bleed

1. Remove wheel and brake pads. Fit bleed block to caliper and turn pad contact adjuster in opposite direction of arrow until it stops.

sram brake bleed

2. Fit lever bleed tool and Bleeding Edge tool to syringes. Add small amount of DOT 5.1 brake fluid to caliper syringe. Fill lever syringe ¾ full of brake fluid and close syringe clamp.

Top tip: When filling syringes, make sure the tube end is fully submerged in oil to prevent any air bubbles entering.

sram brake bleed

3. Adjust brake lever position so the tip of the lever is 75-80mm from the centre line of the handlebar.

sram brake bleed

4. Remove lever bleed port screw using Torx T10 and place to one side. Wipe away any oil that may spill out. Thread and nip tight the ¾ full lever syringe into lever bleed port.

sram brake bleed

5. Remove rubber caliper bleed plug by hand. Insert Bleeding Edge tool in to hole, and push in until you feel and hear a snap.

sram brake bleed

6. Turn bleeding edge tool one turn anti-clockwise to open system.

sram brake bleed

7. Open lever syringe clamp, then holding vertically, gently push plunger down to insert all oil and stop before air enters system.

sram brake bleed

8. Hold caliper syringe vertically. Push up on the lever syringe to draw fluid back up from the caliper syringe. Stop before air enters system at the caliper.

sram brake bleed

9. Turn bleeding edge tool clockwise until it stops to close system.

sram brake bleed

10. Depress brake lever blade and release. Pull on lever syringe to create a vacuum, then press down on syringe to pressurise system. Repeat until minimal bubbles are visible in lever syringe tube.

Top tip: If the oil exiting the system is dark and dirty, then you should repeat the bleed process until the oil in the system is clear.

sram brake bleed

11. Press on lever syringe plunger, then release and close syringe tube clamp. Now remove lever syringe and refit bleed port screw being careful of spilling fluid. Tighten to 1.5-1.7Nm using T10 Torx.

sram brake bleed

12. Remove caliper syringe by pulling on the Bleeding Edge tool; don’t turn the tool. Refit rubber bleed port screw.

sram brake bleed

13. Clean lever and caliper with brake cleaner or isopropyl alcohol to ensure all excess oil is removed.

sram brake bleed

14. Remove bleed block, fit brake pads and wheel. Depress lever so that the pads contact the rotor correctly and adjust caliper position if necessary.

sram brake bleed

SRAM Pro Bleed Kit, £58

The latest SRAM Pro Bleed Kit includes everything you need, along with the Bleeding Edge tool, to service your brake. These professional syringes are easier to use and don’t fail like cheaper ones. You can also get hold of the Bleeding Edge tool separately if that’s all you require.