CNC, Inc.CNC, Inc.

Bleeding and Maintenance

Bleeding

We strongly recommend that you use a pressure bleeder with a rubber bladder that separates the air side from the fluid side. If this is not possible follow the following procedure:

  1. Fill the master cylinder reservoir 3/4 full with clean, fresh brake fluid. Lay the master cylinder lid over the reservoir, but do not tighten it down.
  2. Push and hold the pedal down.
  3. Open the bleeder valve on the caliper, or wheel cylinder, until fluid is released. If you are bleeding a Dual Cylinder Brake Pedal Assembly you will need to open a bleeder screw on the front brakes and the rear brakes at the same time. If you are bleeding a system with a cutting brake in it, follow the directions below.
  4. Close the bleeder valve and release pedal.
  5. Wait 12 seconds and repeat.

Do Not Pump the Pedal
Pumping will only aerate the fluid and prevent complete bleeding. Complete your bleeding procedure all the way around the car. Bleed each caliper until clear, air-less fluid comes out of each bleeder screw. When finished be sure to run master cylinder only 3/4 full of fluid.

Bleeding A System With A Cutting Brake

We strongly recommend that you use a pressure bleeder with a rubber bladder that separates the air side from the fluid side. If this is not possible follow the following procedure:

  1. Fill the master cylinder reservoir 3/4 full with clean, fresh brake fluid. Lay the master cylinder lid over the reservoir, but do not tighten it down.
  2. Push and hold the pedal down.
  3. Open a bleeder screw on right wheel cylinder or caliper. **
  4. Actuate cutting brake handle connected to right wheel. Hold.
  5. Close bleeder screw on right wheel cylinder or caliper.
  6. Release brake pedal. Wait 12 seconds.
  7. Release cutting brake handle. Wait 12 seconds.
  8. Repeat procedures for left brake.
  9. Repeat process until all air is out of system.

** If you are bleeding a system with a Dual Cylinder Brake Pedal Assembly, on step 3 you will need to open a bleeder screw on the front brakes and the rear brakes at the same time.

Brake Check List

  1. Do not exceed 1500 lbs pressure
  2. Use AUTOMOTIVE DOT 3 or 4 brake fluid only
  3. Bleed screws must be pointed up for proper bleeding
  4. Use grade 8 bolts for mounting
  5. Inlet ports are 1/8" pipe thread
  6. Seal all fittings with Loctite - NOT teflon tape
  7. Make sure wheels turn freely after bleeding
  8. Do not use your brake pedal as a foot rest
  9. Test drive

Maintenance

Prior to each racing event or weekend out it is a good idea to follow this checklist to make sure your brakes are up to their maximum potential.

  1. Check for leaks around calipers, pistons, fittings and lines.
  2. Bleed once around the car to replenish the system with fresh fluid.
  3. Check pad wear.
  4. Make sure all wheels rotate in a drag-free condition.

Pad Replacement

When replacing pads you must clean the exposed portion of the caliper piston with brake cleaner or brake fluid before the piston is retracted into the piston housing. This procedure will avoid damage to the piston seals.

When the car is raced weekly, we recommend replacing the seals once at mid season and rebuilding between seasons. For lesser used cars, seal replacement between seasons is fine. Always flush the system with fresh brake fluid after any seal replacement or rebuild.