How to Bleed Formula Hydraulic Brakes (DOT Models)

If you’ve worked through the diagnostic guide and confirmed you need a bleed, this is the procedure for Formula brakes that use DOT fluid: the original R1, R0, RX, T1, and the older Mega and One. The R1R, Cura, and newer mineral-oil Formula brakes use a different procedure (see your manual or send us a note).

Critical: confirm your brake is a DOT model before starting. Formula has shipped both DOT and mineral-oil versions of similar-looking brakes over the years. Using the wrong fluid will destroy the seals in minutes. The fluid type is usually printed on the lever body or the master cylinder cap. If you can’t see it there, check Formula’s site by year and model. When in doubt, don’t pour anything into the system.

This procedure is for DOT 4 or DOT 5.1. Not DOT 5 (silicone, incompatible).

DOT fluid safety

DOT brake fluid is corrosive. It strips paint, irritates skin and eyes, and absorbs moisture from the air. Wear nitrile gloves and eye protection. Have rags ready and wipe every drop the second you see it. Keep isopropyl alcohol nearby to neutralise spills. Cover the floor under your work area.

Used fluid is hazardous waste. Don’t pour it down a drain. Most auto parts stores accept it for recycling.

Never share a bleed kit between DOT and mineral oil systems. Residue from one fluid will damage the seals when used on the other.

Tools and supplies

• A bleed kit. The easiest path is Formula’s own Bleed Kit, which has the right M5 adapters and fittings. Aftermarket options that work: Park Tool BKD-1, Birzman, Epic Bleed Solutions Formula-specific kit, Pedro’s Pro Bleed Kit.
• The red M5 adapters (Formula uses M5, not the larger threads some other brakes use)
• DOT 4 or DOT 5.1 fluid, fresh
• Hex wrenches (Formula uses hex for the bleed port screws, not Torx)
• A piston press. The Loam Goat 5 In 1 Disc Brake Tool has one built in, or use a clean tire lever.
• Torque wrench (needs to read accurately in the 1-2 Nm range)
• Isopropyl alcohol and plenty of rags
• Safety glasses, nitrile gloves
• Repair stand

Step 1: Bike prep

1. Mount the bike in the stand. Angle the bike so the bleed port at the lever is the highest point in the system, with the hose running uphill from caliper to lever. Air bubbles rise, so this orientation gives them a clean path out.
2. Remove the wheel.
3. Use the piston press to push the pistons all the way back into the caliper body. This makes room for the bleed blocks. If your caliper is dual-piston (most Formulas) this still applies; if it’s four-piston, press all four.
4. Remove the pads. (see: How to Replace Your Disc Brake Pads for pad removal.) Set them aside somewhere clean and oil-free.
5. Install the bleed blocks in place of the pads. Use both blocks if you have a four-piston caliper.

Step 2: Bleed kit prep

1. Install the double-ended hoses on both syringes, with the wider over-encapture end facing away from the syringe.
2. Thread the red M5 adapters onto the ends of both hoses.
3. Lever syringe: leave empty. This is the key difference from a SRAM bleed.
4. Caliper syringe: fill ¾ full with fresh DOT fluid.
5. Hold the caliper syringe vertically, hose end up, and gently push the plunger to evacuate air from the hose. Stop when fluid reaches the adapter end. Clip the hose closed.

Step 3: Install syringes

At the lever:

1. Remove the bleed port screw with the appropriate hex.
2. Thread the empty lever syringe into the port. Seat the adapter squarely, cross-threading at this torque (M5) will strip the lever fast.
3. Clip the syringe into the handlebar holder.

At the caliper:

1. Remove the bleed port screw with the appropriate hex.
2. Thread the caliper syringe (¾ full) into the port.

Wipe any drips immediately.

Step 4: The bleed

Push fluid from caliper to lever

Push the caliper syringe plunger to send fresh fluid up through the system into the empty lever syringe. As fluid arrives at the lever syringe, watch for bubbles surfacing in it. Those are the air pockets you’re flushing out.

Halfway through the push, while still pressurised, pull the brake lever and quickly release it. This jolts loose any bubbles trapped against the master cylinder. You may see additional bubbles enter the lever syringe.

Stop pushing before the caliper syringe is fully empty. You need fluid still in it for the next step. The lever syringe should now be partially filled (the same volume you sent up from the caliper).

Pull fluid back down

Hold the lever syringe upright (so air sits at the top, fluid at the bottom). Use the caliper syringe to pull a vacuum, drawing fluid back down toward the caliper. Use slow, long pulls.

Don’t let the lever syringe run dry. If you pull all the fluid out of the lever syringe, you’ll suck air right back into the system. Watch the lever syringe fluid level and stop pulling when it gets low.

Push back up one more time

Reverse direction. Push the caliper syringe to send fluid back up to the lever. By this third pass, any remaining bubbles in the caliper or hose should be gone.

Cap the caliper

1. Clip the caliper syringe hose.
2. Unthread the syringe from the caliper.
3. Quickly reinstall the bleed port screw.
4. Torque to 1.5-1.7 Nm. That’s very light, finger tight plus a small touch with the wrench. Over-torquing the bleed port will crack it.
5. Wipe any spilled fluid with alcohol.

Flush bubbles at the lever

Now to the lever syringe.

1. Push the syringe plunger gently to pressurise.
2. Pull the brake lever and release it. Watch for bubbles entering the syringe.
3. Pull the syringe plunger to create vacuum. More bubbles should rise into the syringe.
4. Push to pressurise again.
5. Pull-and-release the lever a few more times.

Repeat the pressure-vacuum-pump cycle until no more bubbles appear in the syringe.

Cap the lever

1. Push the syringe one last time to leave the system at slight positive pressure.
2. Clip the syringe hose.
3. Unthread the syringe from the lever.
4. Reinstall the bleed port screw with its O-ring.
5. Torque to 1 Nm. Even lighter than the caliper screw. Snug, not tight.
6. Wipe.

Step 5: Test the bleed

Pull the lever hard. It should feel firm with a solid stop, no spongy travel. If it’s still soft, repeat the lever-side flush. Air didn’t all come out.

If front and rear brakes feel noticeably different in firmness, the softer one needs another pass.

Step 6: Reset the bike

1. Remove the bleed blocks from the caliper. Wipe inside the caliper body with alcohol on a clean cloth.
2. Reinstall the pads. Handle by the backing plate only. (see: How to Replace Your Disc Brake Pads)
3. Reinstall the wheel.
4. Pull the lever repeatedly until the pads advance to the rotor and the lever firms up.
5. Spin the wheel. If there’s any rub, realign the caliper. (see: How to Fix a Rubbing Hydraulic Disc Brake)

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

Step 7: Clean the bleed kit

DOT fluid sitting in the kit will eat the rubber seals over time. After every bleed:

1. Flush both syringes and hoses with isopropyl alcohol until no fluid residue remains.
2. Disassemble the syringes.
3. Wipe every fluid-contacted surface with alcohol on a clean rag.
4. Lay everything out to dry before reassembling.

Common screwups

• Wrong fluid. Confirm Formula model is DOT, not mineral, before starting. Verify by checking the lever body or master cylinder cap.
• Sharing a bleed kit with mineral oil brakes. Cross-contamination ruins seals. Keep DOT and mineral kits separate, label them.
• Letting the lever syringe run dry during the pull-back step. Sucks air right back in.
• Over-torquing the bleed port screws. 1 Nm at the lever, 1.5-1.7 Nm at the caliper. A calibrated torque wrench is worth having for this, guessing usually ends in a stripped port.
• Forgetting the O-ring on the bleed port screw. It sometimes sticks inside the port instead of coming out with the screw. Check both ends every time.

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This article is based on Park Tool’s video Formula Brake Bleeding Procedure.