Small reservoir brake master cylinder parts
1. Cork and mesh filter; 2. Tank; 3. Retaining ring; 4. Primary piston with spring; 5. Secondary piston with spring; 6. Lock bolt; 7. Plug; 8. Fitting
Large reservoir brake master cylinder parts
The brake master cylinder is mounted in the engine compartment on a vacuum booster.
Removal
1. Use a syringe to remove some of the liquid from the tank.
2. Place a tray or a rag under the cylinder.
3. Loosen the hose fittings on the master cylinder.
4. Disconnect and plug the tubes.
5. Disconnect the connector from the tank (if provided), unscrew the 2 nuts securing the cylinder to the vacuum booster and remove the cylinder.
Disassembly
Cylinders with a large or small tank are installed on cars; the procedures for disassembling and assembling these units are almost the same, with the exception of reservations.
Before disassembling, purchase a cylinder repair kit.
1. On the cylinder with the small tank, unscrew the tank mounting bolt.
2. Loosen the tank clamps (A) and the fitting (B) and remove the tank.
3. On the cylinder with the large tank, unscrew the screw and remove the tank.
4. Check the condition of the gasket.
5. Clamp the cylinder in a vice, press the pistons and unscrew the lock bolt. Replace the bolt gasket.
6. Press the pistons back again and remove the snap ring.
7. Disassemble the cylinder, paying attention to the order of installation of the parts.
8. Remove the primary piston.
9. Remove the secondary piston by tapping it on a block, being careful not to tilt it, otherwise the cylinder will be scratched.
10. Pay special attention to the springs, which differ for different pistons.
11. Check the condition of the cylinder.
12. If scratches or discolored areas are found, replace the cylinder. Honing the cylinder is prohibited.
13. Replace all parts, installing new ones from the repair kit in the same order. Before assembly, dip the parts in brake fluid.
14. Assemble the pistons, insert them into the cylinder, press them back and tighten the lock bolt.
15. Install the new retaining ring, making sure that the ring fits into the groove.
16. Install the tank gaskets and tank.
17. When installing, fill the cylinder with liquid.
18. Clamp the cylinder in a vice by the flange, fill the tank with fluid, tighten the plugs and press on the piston with a large Phillips screwdriver.
19. Unscrew the plug to let the air out.
20. Screw the plug back on and release the piston.
21. Repeat these steps until liquid starts to come out of the hole under the nipple. Maintain the liquid level in the tank at all times.
22. Repeat the air removal steps for the other hole.
23. Instead of a plug, you can close the hole with your finger.
24. Release your finger after pressing the pistons, after the liquid flows out, close the hole with your finger and release the pistons.
25. After a few seconds, press the plunger again and remove your finger.
26. Repeat the procedure and do the same on the other hole.
27. Once only liquid starts flowing out of the holes, tighten the plugs.
Installation
1. Place the cylinder back in place and tighten the nuts by hand.
2. Screw in the fittings without distortion, manipulating the cylinder.
3. Tighten the nuts and fittings.
4. Add liquid to the tank up to the upper mark and tighten the cap.
5. You can also remove air from the cylinder on a car, working together. To do this, ask your assistant to press the pedal and hold it.
6. Unscrew the nipple and release the air.
7. Tighten the nipple and ask your assistant to release the pedal.
8. Continue until liquid begins to flow out of the cylinder.