Understanding Hydro Boost Brake Systems
The Hydro Boost brake system uses power steering pressure instead of engine vacuum to assist in braking. This type of system is commonly found in diesel vehicles and some heavy-duty applications. Bleeding the brakes on a Hydro Boost system is similar to bleeding a conventional brake system but with a few extra steps to ensure that air is removed from the power steering lines as well.
Preparation
Before you begin, you’ll need a few tools and materials:
- Brake fluid that meets your vehicle’s specifications
- A clear tube that fits the bleeder valves on your brake calipers
- A wrench to fit the bleeder valves
- An assistant to help press the brake pedal
- A clean container to catch old brake fluid
- Protective gloves and safety goggles
- Rags or paper towels to clean up spills
Step-by-Step Bleeding Procedure
Follow this step-by-step guide to properly bleed your Hydro Boost brake system:
Step 1: Safety and Preparation
Ensure the vehicle is parked on a level surface and the parking brake is engaged. Open the hood and locate the brake fluid reservoir and the Hydro Boost unit near the power steering pump. Check the brake fluid level and fill if necessary. Put on your protective gloves and safety glasses.
Step 2: Starting with the Furthest Wheel
Begin with the brake farthest from the master cylinder, typically the rear passenger side. Locate the bleeder screw on the brake caliper.
Step 3: Attaching the Bleeder Tube
Attach one end of the clear tube to the bleeder screw and place the other end into the container to catch the brake fluid. Make sure it’s submerged to prevent air from going back into the system.
Step 4: Loosen the Bleeder Screw
Have your assistant press down slowly on the brake pedal. While they’re holding the pedal down, loosen the bleeder screw slightly to allow fluid and air to escape. Tighten the screw before your assistant releases the brake pedal to avoid sucking air into the system.
Step 5: Repeat the Process
Repeat Step 4 until you see a steady stream of brake fluid without any air bubbles. Check the brake fluid reservoir often and refill it as necessary to avoid introducing air into the master cylinder.
Step 6: Bleed the Remaining Wheels
Move to the next furthest wheel from the master cylinder and repeat the steps above. Continue this process with each wheel until all four have been bled.
Step 7: Bleed the Hydro Boost System
In some cases, after bleeding all four wheels, you may need to bleed the Hydro Boost system itself. This involves turning the steering wheel from lock to lock multiple times with the engine running to purge air from the power steering lines. You may need to consult your vehicle’s service manual for specific instructions.
Step 8: Final Checks and Test Drive
After bleeding the brakes, check the brake pedal for firmness while the engine is running. The pedal should feel firm and not spongy. If necessary, repeat the bleeding process until a firm brake pedal is achieved. Ensure all bleeder screws are tightened and the brake fluid level is correct. Take the vehicle for a slow test drive in a safe area to ensure proper brake function.
Tips:
- Never let the brake fluid reservoir run dry during the bleeding process.
- Use only the type of brake fluid recommended by your vehicle manufacturer.
- Dispose of used brake fluid properly, as it is toxic and harmful to the environment.
- If you experience difficulty or the brake pedal does not become firm, there may be additional issues that need professional attention.
Following these steps should help you successfully bleed your Hydro Boost brake system and ensure your vehicle’s braking system performs optimally. If you are not comfortable performing this procedure, it is advisable to seek assistance from a professional mechanic.