I'm experiencing a sponge like feeling when activating the front brake lever. I have replaced the rear system barke fluid after sensing my rear brakes was not effective. Will replacing the front brake fluid eliminate the spongy feeling? 2007 BMW 1200GS Regards Jacques

Resetting a proportioning valve in a 2001 Ford Explorer typically involves bleeding the brake system to ensure proper brake pressure distribution. The proportioning valve adjusts the amount of brake pressure sent to the front and rear brakes to optimize braking performance. If you're experiencing brake-related issues or have replaced brake components, bleeding the brake system can help reset the proportioning valve. Here's how to do it:
**Tools and Materials Needed:**
- Brake fluid
- Jack and jack stands
- Wheel chocks
- Wrenches
- Brake bleeder kit or clear plastic tubing
**Steps:**
1. **Safety Precautions:**
- Park the vehicle on a level surface and engage the parking brake.
- Use wheel chocks to prevent the vehicle from rolling.
- Wear appropriate safety gear, including gloves and eye protection.
2. **Prepare the Vehicle:**
- Loosen the lug nuts on all four wheels, but do not remove them completely.
3. **Jack up the Vehicle:**
- Use a jack to lift the vehicle off the ground. Secure it with jack stands for safety.
4. **Bleeding Sequence:**
- Start with the brake caliper or wheel cylinder that is farthest from the master cylinder. In most cases, this would be the right rear wheel.
5. **Bleeding Process:**
- Have a helper pump the brake pedal several times and then hold it down.
- Loosen the bleeder valve on the brake caliper or wheel cylinder.
- Fluid and air bubbles should come out. Tighten the valve before your helper releases the brake pedal.
- Repeat this process (pumping, holding, opening, and closing the valve) until you see clear brake fluid without air bubbles.
6. **Repeat the Process:**
- Move to the next farthest brake caliper or wheel cylinder (left front, right front, left rear) and repeat the bleeding process.
7. **Check Brake Fluid Level:**
- Keep an eye on the brake fluid reservoir while bleeding. Make sure it doesn't run dry, as this can introduce air back into the system.
8. **Top Off Fluid:**
- After bleeding all the brake components, top off the brake fluid reservoir with fresh brake fluid to the recommended level.
9. **Test Brakes:**
- Lower the vehicle, tighten the lug nuts, and then fully tighten them in a crisscross pattern.
- Test the brakes to ensure they feel firm and responsive.
Bleeding the brake system is an important maintenance task, especially after working on the brakes or if you're experiencing spongy brakes. If you're unsure about the process or want to ensure proper brake system maintenance, consider seeking assistance from a professional mechanic.

You've obviously still got air in the lines. If you can't remove it, take it to a shop for a pressure bleed.

In this situation, most likely there was a break-down in the brake system. Usually you only have one reservoir that services both front and rear brake systems. But to replace the fluid, obtain a Hayne's Repair manual. They go over brake fluid replacement.

The reason is, you have a rear anti lock brake system. The anti lock valve is located on the frame just underneath the brake master. It is called a RABS valve. Almost impossible to bleed. But it can be done. A dealer has a tool that plugs into the RABS valve which activates the valve constantly moving the valve back and forth. This will then push all fluid and air out of your open bleeder screws in the rear.
I did'nt go to the dealer. i was too stubborn. My solution was to lift the rear of the truck and place on jack stands. Pinch off the rubber brake hoses on the 2 front brakes with a C-clamp or non marring vise grips, this will keep all fluid from going to front brakes. Next adjust the rear brake shoes by tightening the adjuster on the rear brake drums. Tighten the brakes on the rear until the brakes start to drag and the tires no longer spin freely by hand. Attach a bleeder hose to the bleeder screw on the RABS valve, place open end of hose into a jar or canister of brake fluid, so as not to draw in any air. Open the bleeder screw. Start the vehicle up, put it in gear, and let the rear tires spin. (I got up to 25mph on my speedometer) Step on the brake while it is in gear and the tires are spinning. This will activate the RABS valve and cause the air in the RABS valve to bleed. Do this several times. Put vehicle in park, shut off engine, and close the bleeder on the RABS valve. Attach bleeder hose to right rear of the truck, place open end of hose in a canister or jar of brake fluid so no air gets in and open the bleeder screw. Start the vehicle up, put it in gear, and let the rear wheels spin freely. As the wheels spin, you press your foot on the brake pedal, this will activate the RABS valve, and effectively bleed the brakes. Do this a dozen or so times, tighten the bleeder screw and do the other side. Remove clamps from front brake hoses and you will be go to go. All this may seem a bit extreme, but it is the only effective way to bleed a Rear Anti Lock Brake System on an early Ford. All the steps I laid out are necessary. You cannot skip one. The reason why the rear has to be in the air, is that there is a sensor mounted to the rear differential that senses wheel spin(or axle spin), this goes directly to the RABS valve and tells it that the tires are moving at a certain speed, and to activate the Rear Anti Lock Brakes when the brake pedal is depressed. It will not activate if it does not sense movement. The reason for pinching off the front brake lines, is that there are needle valves in the master cylinder and they will send too much fluid to the front calipers, and stifle or hinder the amount of fluid needed to go to the rabs valve and ultimately the rear wheel cylinders. It seems like a lot, and it is, but I did it and it works. Good luck

Just take your old line off and replace it with the new line. Be careful because the brake fluid will damage your paint if it's DOT 4. One you have replaced the brake line, fill the master cylinder with the proper brake fluid. Open the bleeder valve and let gravity do it thing. Usually once the fluid starts to flow out of the bleeder valve, all the air is gone as well.

But if the brake lever still feels spongy or no brake at all, first bleed the master cylinder. Squeeze the hand lever and hold it while you loosen the union bolt on the end of the master cylinder. Once the pressure bleeds off, close the valve and repeat the process until you get no air bubbles. Then, move down to the brake caliper and do the same thing until you get no air and a full brake lever. You must do it in this order exactly. Squeeze the lever, open the valve, close the valve, let go of the lever. Do not allow the master cylinder to run dry during the bleeding process.

Good Luck
Steve

You need to bleed the whole system. Once this is done it should work better. Make sure you are not low on brake fluid. If the front brakes are disk brakes and the rear are drum breaks, the front really does most of the stopping, the back jjust keeps the car from spinning or swaying. But the main stopping power is in the front breaks. They need to be bled correctly, make sure brake fluid is up and make sure emergency break is not engaged. The emergency break uses a lever and cable to activate the rear brakes. The emergency breaks don't run off brake fluid...

please give good ratings, they are very important...

there could be a possibility that the brake fluid is leaking past the seals in the master cylinder on the handle bars and slowly apllying the brake

check master cylinder,may have air in line also.

sounds like you are getting a false ABS activation. Check the axles at the outer cv joints to see if the sensor rings for the ABS are cracked. A common problem.

Only two things should normally activate the light:

Parking Brake engaged switch.

Low Fluid level in master cylinder.

I don't think you did any work to the Parking brake, but you should check it to be sure.

I believe that you would have double checked the fluid level, but please check it again.

Other things that could activate the light would be a worn or leaking master cylinder; improper brake fluid type; a damaged brake booster diphragm .

I have attached a link with excellent info on how a brake system works here.

Also, does the light always stay on, or only when you apply the brakes?

Brian