How to Bleed Magura Hydraulic Brakes

How to Bleed Magura Hydraulic Brakes

If you’ve worked through the diagnostic guide and confirmed you need a bleed, this is the procedure for Magura MT-series and similar mineral-oil brakes with flat-bar levers (MT2, MT4, MT5, MT7, MT8, MT Trail, and the older Marta variants).

Magura uses mineral oil, not DOT. Specifically, Magura recommends their proprietary Royal Blood mineral oil. Generic mineral oil will mostly work but isn’t officially supported and may affect long-term seal life. Never put DOT fluid in a Magura brake. It will destroy the seals immediately and the brake will fail.

If your Magura is one of the rare older models that shipped with DOT (some early Martas), check the lever for fluid markings before starting. When in doubt, don’t pour anything into the system.

Mineral oil safety

Mineral oil is less aggressive than DOT (no paint damage, less skin irritation), but it’s still messy and slippery. Wear gloves to keep oil off your skin. Eye protection is still a good idea. Lay rags under your work area and wipe up spills with isopropyl alcohol.

Don’t pour used oil down the drain. Most auto parts stores accept it for recycling.

Never share a bleed kit between mineral and DOT systems. Residual contamination ruins seals on either side.

Tools and supplies

  • A bleed kit. The easiest path is Magura’s own Bleed Kit, which includes Royal Blood and the right M6 adapters. Aftermarket options that work: Park Tool BKM-1, Birzman, Epic Bleed Solutions Magura-specific kit.
  • The black M6x1mm caliper adapter and the blue M6x0.75mm lever adapter from the kit. Magura uses M6 thread, not the M5 you’ll find on SRAM and Formula. Double check by matching threads on a screw before installing.
  • Magura Royal Blood mineral oil (or compatible)
  • Hex wrenches (sizes depend on model)
  • T25 Torx
  • A piston press. The Loam Goat 5 In 1 Disc Brake Tool has one built in, or use a clean tire lever.
  • Bleed blocks (in the kit)
  • Isopropyl alcohol and rags
  • Gloves, safety glasses
  • Repair stand

Step 1: Bike prep

  1. Mount the bike. Angle it so the lever bleed port is the highest point in the system and the hose runs upward from caliper to lever with no sags.
  2. Remove the wheel.
  3. Press the pistons all the way back into the caliper using the piston press.
  4. Remove the pads. (see: How to Replace Your Disc Brake Pads)
  5. Install the bleed blocks. If the caliper doesn’t have a pad retention screw (some MT models don’t), hold the blocks in place with a rubber band.
  6. Rotate the lever on the bars so the bleed port faces straight up.

Step 2: Bleed kit prep

  1. Attach the hose with threaded fittings on both ends to the syringe (threaded end into syringe).
  2. Thread the black M6x1mm adapter to the other end of the hose (for the caliper).
  3. Fill the syringe nearly full with fresh mineral oil.
  4. Hold the syringe vertically with the hose pointing up. Pull back on the plunger to draw air out, then slowly push to expel air until only fluid remains in the syringe and hose.
  5. Set the syringe aside.
  6. Attach the syringe holder above the brake caliper.

Step 3: Connect at both ends

At the caliper:

  1. Remove the caliper bleed port screw.
  2. Thread the syringe (with black M6 adapter) into the caliper port. Hand-snug.
  3. Clip into the syringe holder.

At the lever:

  1. Remove the lever bleed port screw.
  2. Thread the blue M6x0.75mm adapter into the lever port.
  3. Install the bleed funnel on top of the adapter. The adapter prevents you from over-tightening into the lever itself.
  4. Remove the stopper from the funnel.

Step 4: The bleed

Push fluid up through the system

Push the caliper syringe plunger slowly to send fresh fluid up through the hose and into the funnel at the lever. Watch the funnel for bubbles surfacing in the new fluid. Those are air pockets being flushed out.

Stop pushing before the syringe is fully empty (leave some fluid in it).

If the fluid coming up is dirty, that’s old contaminated oil. Continue pushing until clean fluid is reaching the funnel, then stop. Plug the funnel, remove and discard the dirty fluid, refill the funnel with the same amount of clean oil, and continue.

Pull fluid back down to caliper

Slowly pull the caliper syringe plunger back. This draws fluid (and any remaining air) back down from the funnel toward the caliper. Use long, slow strokes to create a real vacuum that pulls bubbles out of the caliper body.

Don’t let the funnel run dry. If the funnel empties, you’ll suck air right back into the system. Watch the level and stop pulling when it gets low.

Push back up one more time

Reverse direction. Push the caliper syringe again to send fluid back up to the funnel. By this third pass, the system should be free of bubbles.

Dislodge bubbles at the lever

While the system is full and pressurised, partially squeeze and release the brake lever a few times. This shakes any bubbles loose from inside the lever body. They’ll surface in the funnel.

Cap off

  1. Leave the syringe at the caliper for now.
  2. Install the stopper in the funnel to seal it.
  3. Have a rag ready. Unthread the blue adapter from the lever.
  4. Reinstall the lever bleed port screw with its O-ring.
  5. Torque the lever screw to 0.5 Nm. This is very light. A calibrated torque wrench is essential here.
  6. Wipe.
  7. Have the caliper bleed port screw ready. Unthread the syringe from the caliper.
  8. Reinstall the caliper bleed port screw.
  9. Torque the caliper screw to 4 Nm maximum. Over-tightening cracks the port.
  10. Wipe.

Step 5: Test and reset

Squeeze the lever hard. It should feel firm. If it’s soft, air is still in the system and you need to repeat the bleed.

If firm:

  1. Wipe lever and caliper with alcohol on a clean rag.
  2. Rotate the lever back to your normal riding position.
  3. Remove the bleed blocks.
  4. Reinstall the pads. (see: How to Replace Your Disc Brake Pads)
  5. Reinstall the wheel.
  6. Pull the lever repeatedly until the pistons advance and the lever firms up.
  7. Spin the wheel. If it rubs, realign the caliper. (see: How to Fix a Rubbing Hydraulic Disc Brake)

If you installed new pads at the same time, bed them in. (see: How to Bed In New Brake Pads)

Step 6: Clean the kit

For mineral oil kits, cleaning is less critical than for DOT (mineral oil doesn’t corrode), but still good practice.

  1. Empty fluid from syringes and hoses back into the bottle (if clean) or into a waste container.
  2. Let hoses drain.
  3. A small amount of residual mineral oil in the syringe is fine, no need to fully disassemble unless it’s been stored a long time.

Common screwups

  • Wrong fluid. Confirm Magura is mineral, not DOT, before anything else.
  • Wrong adapter thread. Magura is M6, SRAM and Formula are M5. Don’t force the wrong adapter in.
  • Over-torquing the lever bleed screw. 0.5 Nm is barely snug. Trust the torque wrench.
  • Letting the funnel run dry during pull-back. Air goes right back into the system.

Based on Park Tool’s video Magura Brake Bleeding Procedure.

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