In this guide, you will find step by step instructions on how to replace BMW brake hose from brake caliper to the brake line. Over the years your BMW brake line may start to show signs of crack and wear.
It is recommended to inspect your BMW flex brake hoses for cracks and lines for corrosion at least once a year. A worn BMW brake hose may burst and cause loss of braking power while driving. If any of your BMW brake lines show signs of wear, replace them as soon as possible.
Instructions on this article will help owners of 1-series, 3-series, 5-series, 6-series, 7-series, X1, X3, X5, z3, z4, and other models.
- BMW leaks brake fluid from flex brake line
- Low brake fluid level on the reservoir
- Brake warning light stays ON
- No brakes on one side if the brake line fails completely
- Fluid brake leak when parked
- Poor braking performance
- Brakes feel soft when pressing BMW brake pedal
BMW brake lines are made of reinforced rubber hoses which are build to withstand hydraulic pressure, bending and heat. On older BMWs, the brake hose may start to show signs of cracking, bulking or complete failure.
A soft brake pedal may indicate that your flexible brake lines are failing or there is air in the brake lines.
How to replace BMW brake hose
Below you will find step by step instruction on how to replace BMW hydraulic hose, and a list of tools and parts that you will need.
What you will need
What you need to know
- Brake fluid
can damage your car paint. Rinse it off with water if it falls on the car paint.
- It is recommended but not required to bleed the ABS
pump, in addition to to the brake caliper
- Spray penetrating oil
on the old hose connections the night before when possible.
- Use the 11m brake nut wrench
to avoid rounding off the locking hut on the brake line.
- Test the brakes before driving away. The brake pedal should be hard when the air bleeding is completed correctly.
- Ensure your new brake hose is the same length as the old BMW brake hose.
- Jack up the car and remove the wheel where you need to replace the brake line.
- Spray penetrating fluid on the brake line connection and bolt that secures the brake line to the caliper.
- Open the hood and locate the brake fluid reservoir. On some BMW models, the brake fluid reservoir is located below the cabin microfilter. Remove the plastic housing to access the brake fluid reservoir. Remove cap from the brake fluid reservoir. Remove filter using a needle nose pliers. Pump the brake fluid out of the brake reservoir. Remove as much brake fluid as you can.
- Disconnect flex brake hose where it connects to the brake line. Use an 11mm open end wrench to loosen the union bolt where the flexible brake hose connects to the metal brake line.
- Unscrew BMW brake line from the caliper. Use a 14mm wrench to unscrew the brake line from your BMW brake caliper.
- Install new BMW brake hose. Screw the new BMW brake line into the brake caliper. Torque the brake line that mounts on the brake caliper to approximately 20Nm or as recommended by the manufacturer. Secure the brake line on the strut brackets where the old brake line was secured.
- Connect the flex brake line to the metal brake line. Torque the union bolt to approximately 15Nm or as recommended by your BMW dealer.
- Add Brake Fluid. Fill the brake fluid reservoir with recommended BMW brake fluid. (If you are replacing more than one brake line, replace the next BMW brake line before moving to the next step.)
- Bleed Brakes. The next step is to bleed BMW caliper and brake lines. This step requires two people. Start with the brake caliper furthest from the brake reservoir. Loosen the bleed screw on the brake caliper. Pump the brakes until brake fluid comes out of the bleed screw then tighten the screw. Repeat the brake bleeding procedure a few times until no more air remains bubbles are coming out of the bleed screw. Tighten the bleed screw while your friend is keeping the brake pedal pressed.
- Check Brake Fluid Level Check the brake fluid level and add brake fluid if necessary.
- Check Brakes Lower the vehicle. Install the wheel on the car. Before driving off, test the brakes to ensure your brakes are working properly.
- Inspect the hydraulic brake line for leaks after a day to ensure there is no leaks at the connections.
BMW Brake Line Replacement & Cost
Average cost to replace a BMW brake hose by a local mechanic or car dealer will cost between $150 and $510. If you replace one BMW brake hose yourself expect to spend between $30-$80 for a new BMW brake hose, flu, d and basic tools.
A set of four new BMW brake lines can range between $80 and $150 for parts only. Having the dealer replace all four brake hoses can range from $800-$1150.
Most BMW brake lines don't need to be replaced unless the car is over 10 years old or has over 100,000 miles and show signs of wear.
Frequently Asked Questions
How long is a BMW brake hose?
- BMW brake hose can range between 40 cm and 45 cm. BMW brake hose length varies by model.
Would a damaged brake line fail my safety MOT inspection?
- Yes, in most states and countries you will fail the safety test if your brake lines show signs of excessive wear.
Do I need to use thread locker on the brake hose threads?
- No. Torque the brake hose to the recommended specifications is enough.
I stripped the locking nut, what should I do?
- Spray penetrating oil on the nut. Give it about 15 min then use vise grip pliers to get the nut loose.
My BMW brakes feel soft after replacing the brake hose.
- If you replaced your BMW brake line or hose and the brakes feel soft, repeat the procedure to bleed the brake system on all four wheels.
If replacing all BMW brake hoses, which brake horse do I replace first?
- It doesn't matter which line you replace first. The important step is the bleeding procedure. Start with the wheel furthest distance from the brake reservoir, which will be passenger side rear.
Additional BMW Brake Bleeding Resources
- BMW E30/E36 Brake Replacement | 3-Series by PelicanParts
- BMW Brembo Brake Flush and Bleed (Getting Ready for the Track!) by Kies Motorsports