Genuine Mazda MX-5 Miata Brake Master Cylinder

Mazda MX-5 Miata Brake Master Cylinder Parts and Q&A

• Master Cylinder
  NE55-43-40ZA
  Q: What steps should be taken before overhauling the Brake Master Cylinder on Mazda MX-5 Miata?

  A:

  Prior to making the decision of overhauling the master cylinder, inquire about the availability and price of a new or a factory rebuilt unit as well as the availability of rebuild kit. In case you want to re-assemble the cylinder, examine the bore. Start by tracing the wiring harness out of the master cylinder to the electrical connector of the fluid level warning switch and unscrew it. Gently loosen the brake fluid reservoir cap and pump out all of the fluid possible using a syringe, and make sure that the level sensor is continuous at fluid level below the MIN level. Have rags underneath the fittings and ready caps or plastic bags to wrap the end of the lines on removing them, but take care of spillage of the brake fluid as it may ruin paint. Relax the end connector of the brake lines entering the master cylinder with a flare-nut wrench in order to avoid flattening the flats. In 2006 and subsequent models, loosen hose clamp, and remove the hose that links the brake master cylinder reservoir to the clutch master cylinder, being ready to receive any spilled brake fluid. Disassemble the nuts and washers holding the master cylinder to the power Brake Booster and unload the brake lines off the master cylinder pushing the ends back into the main booster to avoid contamination. Slide the proportioning valve mounting bracket off the studs, and remove the master cylinder off the studs, again carefully not to spill the fluid. When using older models that are older than 2005, get the appropriate rebuild kit before proceeding to undertake the process of overhaul as this will include the required replacement parts and guidelines. Take out the reservoir holding screw, pop off the reservoir then peel off the grommets. Insert the cylinder into a vise and with a punch or a Phillips screwdriver press the pistons until they hit the other end of the master cylinder to hold them in place and remove the stopper bolt or screw. The snap ring at the end of the master cylinder is carefully removed, then the internal components may be removed out of the bore, taking note of the correct sequence of the components to be used in their reassembly. Examine the bore of the master cylinder to check if it has any score marks or damage which means that a new master cylinder is needed. Install all the components in the rebuild kit, and rub used components with brake system cleaner and lubricate all components with clean and fresh brake fluid during the installation. Have the assembled parts push into the bore, bottoming them in the end of the master cylinder and then screw in the stopper bolt. Again push in on the main piston and screw in the new snap-ring, in the groove. Install the reservoir grommets, reservoir and reservoir mounting screw. Bench bleed before installation: To offer a master cylinder a chance to be filled, the cylinder needs to be mounted in a vise, threaded plugs were placed in the holes of the brake line outlets, and the reservoir was filled with the recommended brake fluid. Take out one plug and force the piston assembly in the bore to release air and then push the plug in the bore and release the pressure on the piston. Continue until all the brake fluid has been forced out of the outlet hole, being careful not to allow the reservoir to empty. In models built in 2006 and thereafter, the master cylinder cannot be reconstructed; replace it with a rebuilt or new one, and the reservoir can be purchased separately, where required. In case the old grommets on the reservoir and the master cylinder are leaking, change them. Fit the master and the proportioning valve bracket on top of the studs on the power brake booster and screw on the nuts loosely only to start with. Insert the brake line flare nuts into the master cylinder pushing it slightly so that it can easily be threaded. Install the rest of the brake line to the master cylinder attaching the union bolt with a new sealing washer on each side of the fitting. screw the master cylinder mounting nuts and union bolt to the defined torque, tighten the brake line flare nuts by a flare nut wrench. Fill up the master cylinder reservoir with fluid, bleed the master cylinder and brake system by having an assistant depress the brake pedal and loosen the fitting so that air and fluid can emit and repeat this action with all fittings and ensure that the brake system worked properly before driving the vehicle.