If the brake lever pulls farther than it should or the brake lever feel is spongy, the brakes need to be bled. To do this a bleed kit compatible with Zoom brakes and mineral oil is required.
Setting Up Bleed Kit
Find the following parts (see picture below):
Fitting A - this one is the smallest one in the kit and measures 3.8mm at the threads.
Fitting B - this one measures 5.7mm at the threads
for more detailed instructions on adapters see the following link
Use Tool C to install fittings onto the clear hose for the syringe. You can clamp the hose with this block while you twist and push the fittings into place on the clear hose. Put a black syringe adapter on one end, a red clamping lock on the hose itself, and fitting A on the other end as shown below.
Use fitting B, adding an o ring to the nipple end as the adapter for the funnel.
Push the locking collar on and rotate it to until it clicks.
You will also need the plunger for the funnel.
Here is the kit set up for bleeding including a T15 for the caliper bleed port screw and T20 torx for lever bleed port screw.
Fill the syringe with mineral oil and purge the bubbles out of it. 10ml is enough for the front brake, for the rear use 20ml
Remove the wheel from the bike.
Remove the brake pads from the caliper (if you are careful and work clean you can bleed with them in, but getting oil on the pads will require you to replace them). To do so bend the cotter pin open and pull it out. Then pull the pads out from the top of the caliper
Install the bleed block between the pistons. Secure it with a rubber band.
Remove the bleed port screw with a T15 tool (see picture above for bleed port location). Make sure to remove the o-ring that is in the opening of the caliper.
Thread on the syringe.
Remove the bleed port screw on the brake lever and thread on the funnel. Make sure the stopper is removed on the funnel. It helps to position the lever to its level.
Push the plunger on the syringe at the caliper. This will push the oil up into the brake system. Make sure you do not push any bubbles into the caliper (this should not happen because you already removed them from the syringe earlier). You will see the oil flow into the funnel. Then lock the red clamp on the syringe hose.
Put the stopper in the funnel. This will slow the flow of the oil at the caliper when you remove the syringe.
Get your T15 and bleed port screw ready (make sure the o-ring is on the bolt). Un-thread the syringe at the caliper and thread in the bleed port screw as fast as you can to minimize oil flow when its open. Wipe any excess oil that ran out.
Pull out the stopper on the funnel and pump the brake lever 5 times. Then install the stopper again.
Remove the funnel from the brake lever and set aside. You can dispose of the mineral oil that is collected inside the funnel.
Install the bleed port screw with the T20 tool.
Clean up any oil with alcohol if you had leaking or spilling.
Remove the bleed block and install the brake pads.
Install the wheel and test ride.