Here's a general outline of the procedure. Specific steps may vary slightly depending on the exact model of your 1990 Civic. Always consult a repair manual specific to your vehicle's year and model for detailed instructions and diagrams. A Haynes or Chilton manual is a good investment.
Tools You'll Need:
* New Brake Master Cylinder: Make sure you get the correct part for your specific Civic model.
* Wrench set (metric): Various sizes will be needed.
* Socket set (metric): Again, you'll need a range of sizes.
* Brake fluid: DOT 3 or DOT 4, as specified in your owner's manual.
* Catch pan: To collect the old brake fluid.
* Clean rags or shop towels: Brake fluid is corrosive.
* Pliers: Possibly needle-nose.
* Screwdrivers (Phillips and flathead): May be needed depending on your car's configuration.
* Brake bleeder wrench: For bleeding the brakes after the replacement.
* Tubing and a container to collect brake fluid during bleeding: To avoid spillage.
* A helper: Bleeding the brakes is much easier with a second person.
Procedure:
1. Safety First: Disconnect the negative battery cable. This will prevent accidental shorts.
2. Fluid Level: Check the brake fluid reservoir level. Top it off if necessary. You'll lose a significant amount of fluid during this procedure.
3. Drain the Reservoir: Carefully remove the brake fluid reservoir cap and use a clean rag or syringe to drain most of the fluid into your catch pan.
4. Disconnect Components: This will vary depending on your model, but it generally involves disconnecting the brake lines from the master cylinder. Be prepared for some brake fluid to spill. Have your catch pan ready. Use a wrench to loosen the fittings, then carefully unscrew them by hand. Note the location of each line for reassembly.
5. Remove the Master Cylinder: Locate the master cylinder mounting bolts. These are usually on the firewall. Unscrew and remove the bolts. The master cylinder should now come out. You may need to gently pry it loose.
6. Install the New Master Cylinder: Carefully install the new master cylinder, aligning it with the mounting holes. Tighten the mounting bolts securely but do not overtighten.
7. Reconnect Components: Carefully reconnect the brake lines to the new master cylinder, ensuring a tight seal. Tighten the fittings appropriately. Double-check that all lines are connected to the correct locations.
8. Fill the Reservoir: Fill the brake fluid reservoir to the appropriate level, checking your owner's manual for the correct fluid type and level.
9. Bleed the Brakes: This is crucial to remove air from the brake lines. This process usually involves opening each bleeder valve at the wheel calipers one at a time, while having a helper pump the brake pedal. Brake fluid should flow out of the bleeder valve. Tighten each bleeder valve after bleeding. Repeat this process until no more air bubbles appear. Refer to your repair manual for detailed instructions on bleeding your specific braking system.
10. Check for Leaks: Inspect all connections for leaks. Top off the brake fluid reservoir as needed.
11. Test the Brakes: Carefully test the brakes several times to ensure they are functioning properly. If the brakes feel spongy or if the pedal goes all the way to the floor, there's still air in the lines, and you need to re-bleed the brakes.
12. Reconnect the Battery: Reconnect the negative battery cable.
Important Considerations:
* Brake Fluid is Corrosive: Handle brake fluid carefully to avoid skin contact. Clean up any spills immediately.
* Air in the Lines: Air in the brake lines can lead to brake failure. Thoroughly bleed the brakes after replacing the master cylinder.
* Professional Help: If you are uncomfortable with any part of this process, take your car to a qualified mechanic. Brake failure can be fatal.
This is a simplified guide. Always refer to a repair manual specific to your 1990 Honda Civic for detailed instructions and diagrams. Remember safety first! Brake failure is extremely dangerous. If you are unsure about any step, seek professional assistance.
