Bleed proportioning valve

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.

To my knowledge, the porportioning valve can't be bled using the ABS bleed feature of a scan tool and has to be manually bled.

The brakes will need to be bled normally, and GM has a depressor tool specifically made to be installed on the valve while bleeding the brakes: J-39177.

You'll have to bleed the front and rear brakes as normal, but with the tool installed in order to remove the air trapped in the valve.

it is a load proportioning valve that adjusts the proportion of brake pressure according to the load on the vehicle
best to get a new unit and replace it then bleed the air out of the brakes

Proprtioning valve might be stopping fluid going too back wheels

None of those things . Just bleed the brakes normally starting from the longest line and ending with the shortest. The proportioning valve will always let brake fluid through, just not enough to lock up the rear brakes until you press heavy on the pedal . It is there so that full pressure to the large front brakes is reduce in proportion to the smaller rear brakes.

check for fluid before and after the proportioning valve by disconnection the line after the valve and applying the brakes, if no fluid after valve try before valve if fluid is there then it is a bad proportioning valve. you did bleed the master cylinder before connecting the brake line and trying to bleed the brakes all at once right? If the master cylinder was not bled first then a lot of air may have been forced into the rest of the brake lines.

All bleeding is done at each caliper and wheel cylinder. The proportioning valve has no bleeder. The proportioning valve makes the front brakes engage before the rears do to prevent the rear brakes from causing a sideways skid.

yes, if you are trying to bleed the back lines the proportioning valve can possibly reduce pressure to the rear. Are you pumping up the pedal to bleed? In this car, the recommended procedure is to start with the pedal up, open the bleeder, push the pedal down, close the bleeder, allow the pedal to retract, wait 5 seconds, repeat. OK?

You are correct in assuming the proportioning valve,but it may not be bad,if it detects,loss of fluid pressure,it will shut down those brake lines.Try bleeding the master cylinder,then the wheels,and you may have to do it a couple of times,this will allow the proportioning valve allow the wheels with fluid pressure,if this was at all helpful,please rate,thank you,

The problem is probably that you must do the lr before moving to the front. The air in the lr will make it too spongy to bleed the front.
A wheel cylinder is only $25, so you might as well just replace it. And if you use vasoline or brake lube on the bleeder, it will not rust up on you next time.

Proportioning valves are not supposed to block a bleed. They can malfunction, but should not supposed to. And if you have the back working, that should reset the proportioning valve anyway. You can't leave the back. It must be finished.