Jim Smart
September 1, 2000

What Is A Proportioning Valve?
A proportioning valve controls brake pressure to the rear brakes. When we apply brakes, we want strong brake pressure in front, and less pressure in back because the front brakes should always be the dominate binders. If the rear brakes come on too soon or with more aggressiveness than the front brakes, control of the vehicle can be lost. Remember: front brakes first, then the rears.

The Bloody Truth
Do you know how to properly bleed brakes? Baer Brakes stresses the use of the best brake fluids available. Most recommended is Performance Friction’s Z-Rated fluid (#90016). If this isn’t available, opt for Ford’s HD #C6AZ-19542-AA brake fluid instead. What Baer likes most about these fluids is the way they’re packaged. Plastic containers allow moisture to get into brake fluid just sitting on the shelf. Use brake fluids sold in cans for best results.

When you fill the master cylinder with brake fluid, always take it easy and don’t aerate the fluid. Begin bleeding with the farthest brake from the master cylinder. You need clear tubing and a clear plastic or glass jar. Fill the jar just enough to submerge the end of the plastic tube. Have a partner apply and maintain pedal pressure. With the clear hose snug around the bleeder, open the bleeder with a wrench and observe fluid flow. Have the partner gently pump the brake pedal until all air and dirty fluid has escaped. Continue this process until you have clean fluid flow, free of air bubbles. Always close the bleeder with the pedal at the floor—this eliminates the risk of air being drawn back into the system.

Move along to the left/rear brake and repeat the process. Check the master cylinder for fluid and never allow it to run dry. Move the right/front brake and bleed it the same way. Then bleed the left/front brake.

When the bleeding is finished, you still have work to do. Take a block of wood or plastic hammer and tap the brake calipers, dislodging any trapped air bubbles. Bleed the front brakes again, beginning with the right, then left. Make sure all surfaces are clean and free of brake fluid. Use a brake cleaner for this purpose. Brake cleaner has a very high evaporation rate and dries quickly.

After you have driven the vehicle for a couple of days, we suggest going back and bleeding the brakes a second time to ensure all air has escaped. Follow the same procedure for best results.

Types Of Brake Pads
Stainless Steel Brakes tells us there are three basic kinds of brake pads: Organic, semi-metallic, and full-race. Which one should you choose and why?

  • Organic pads are the most common brake pad designed for ordinary use. In regular use, without abuse, these guys should go 30,000 to 40,000 miles.
  • Semi-metallic pads are better than organic because they handle and stand up to heavy use better. Because semi-metallic pads create more brake dust than organic pads, they dirty wheels more quickly.
  • Full-race pads are designed to endure high-heat, severe-duty service. These pads work better when they’re hot—on the racecourse or a canyon road. In regular street use, they’re noisy. They chatter when they’re cold. And they will stop you aggressively in most situations.