No brake fluid is getting to the rear brakes

I have been trying to figure out why my rear brakes are not getting any brake fluid. This problem just occurred this week. I had to replace the master cylinder and also the front right caliper because someone put power steering fluid instead of brake fluid in the master cylinder. My van has an ABS system. Before mounting the master cylinder, I pressurized it. To try to gravity bleed the brakes, my friend and I put the van on level ground and all four bleeder valves opened at each wheel. However, we could not get any fluid to come out at the rear brakes. So we closed the rear bleeders and worke
Experienced mechanics share their insights in answering this question :
As far as the brake issue, yes, there needs to be a check to see if there is brake fluid entering into the proportional valve. If there is fluid supply to the valve but not out then the valve will need to be replaced. Any electrical faults in the rear ABS system are generally indicated with a light illuminated and if so, then the flash codes can be read out. But with no light illuminated then there most likely no electrical failures in the system. If the source from where the brake fluid supply cannot be located, then you may want to enlist the help of a mechanic, such as one from YourMechanic, to help with the diagnosis of your brake system.

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If you are having trouble bleeding the rear brakes on your, it`s most likely due to a damaged proportioning valve. This valve manages and directs brake fluid to the rear brakes. When this valve goes bad, there will be little to no brake fluid being sent to the rear brakes.
Brake Fluid Low but No Visible Leak? While a leak is many times the cause of low brake fluid, there are a few other possible culprits: Leakage into the brake booster. Sometimes brake fluid can leak internally into the brake booster.
IMPORTANT: A drop in brake fluid typically indicates that your brake pads have worn to the point of needing maintenance. Be sure to have your brakes checked by a professional. CAUTION: DO NOT USE BRAKE FLUID OTHER THAN THE SPECIFIC TYPE RECOMMENDED FOR YOUR VEHICLE. Do not overfill.
As you push the brake pedal, this pressurized fluid moves through the brake lines to the calipers and applies pressure to your brake pads against the rotors. This in turn causes friction to go to the tires so they will stop. When you don`t have enough brake fluid, your vehicle may not be able to stop properly.
This can be due to a number of problems: a leak in a brake line, a loss of pressure within the master cylinder itself due to a failed seal, or air being introduced into the braking system. Your first reaction to encountering spongy brakes should be to rapidly pump the brake pedal with your foot.
A common problem when rebuilding rear drum brakes is that the brake cylinder has too much air or fluid in it causing the brake shoes to be pushed too far out. Then the brake drum won`t go back on as you experience.
A worn or malfunctioning master cylinder. If the master cylinder isn`t performing as designed, it may need to be replaced. Defective replacement cylinder. If, after the master cylinder has been replaced and the system has been bled, and still your brake pedal goes to the floor, the new master cylinder may be defective.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

No brake fluid is getting to the rear brakes
ANSWER : As far as the brake issue, yes, there needs to be a check to see if there is brake fluid entering into the proportional valve. If there is fluid supply to the valve but not out then the valve will need to be replaced. Any electrical faults in the rear ABS system are generally indicated with a light illuminated and if so, then the flash codes can be read out. But with no light illuminated then there most likely no electrical failures in the system. If the source from where the brake fluid supply cannot be located, then you may want to enlist the help of a mechanic, such as one from YourMechanic, to help with the diagnosis of your brake system.

Low brake pedal and anti-lock brakes are not kicking in.
ANSWER : The brake pedal is working to stop the vehicle, but there may be air in the controller unit causing the ABS brakes to not function. I recommend bleeding the brake system from the farthest location from the master cylinder to the master cylinder including the ABS unit. If the brakes are still spongy after a full bleed, then the controller will need to be replaced. If you need further assistance with your brake pedal being spongy, then seek out a professional, such as one from Your Mechanic, to help you.

Rear brake job
ANSWER : Hello, thank you for writing in. These situations are understandably questionable. The service providers at a lot of common oil changing and tire repair centers will quote you for a variety of things that can be updated. This does not always mean you are in dire need for more repairs. If braking seems to be harder, spongy, or takes longer, then you have reason to be concerned. Otherwise, you should check the amount of brake pad material left on the calipers. This can be visually inspected without too much trouble. Remove the wheel and physically measure the amount left, compare them to your vehicle specifications. It is a little early to worry about brake fluid or the rotors. However if the brake fluid is low, the rotors are warped from a hard stop, or there are obvious issues you should look into the system further. Only further inspection will confirm or deny the recommendations. For a second inspection, contact our service department to schedule an appointment.

Rear brakes not grabbing – 1995 GMC K2500
ANSWER : Hello. It is not in the ABS, but may be the proportional valve not giving the correct pressure split front to the rear. The vehicle never had enough pressure for the rear brakes. Have the rear shoes adjusted properly if you have drum brakes. You should check to see if there is an updated part to replace the old one. If you would like to have this done, a certified technician from YourMechanic can inspect the brake system and let you know what repairs are needed.

Replaced front rotors an brakes. Pedal is hard to press. Not even getting fluid to the rear brakes.
ANSWER : Hi there. There could be several problems here; seized brake components on the rear, failed proportioning valve, failed master cylinder, failed brake booster. How do you know there is no fluid getting to the rear brakes? Are the front brakes working at all? This could be a serious safety concern and truly needs a qualified technician to perform an inspection. Having a qualified technician perform the inspection will avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a brake pedal is hard to press inspection.

Hard brake pedal and rear brakes locking up.
ANSWER : Hi. I will help you with this issue you are having with your 2001 Durango. Unless you bled the master cylinder, it is possible there is still air in the system. If you car is equipped with ABS, air could have also gotten trapped in the ABS modulator. If ABS equipped, a bi-directional scan tool would be essential to manually activate the ABS system to clear air from that segment of the lines while you are bleeding the system. It is also possible that in all of this work somehow the proportioning valve has been affected causing the desired pressure differential, front versus back, to get out of spec. Using a 2,500 PSI gauge, you can check the pressures at each wheel and that will definitely give you a clue as to which brake circuit is the issue (or both), whether the proportioning valve is working properly and whether the line pressures at each wheel are within spec. Should you need a second opinion, by all means feel free to contact YourMechanic for assistance and we will diagnose and repair the issue for you.

Changed brake master cylinder, bled 10 times, and the pedal is soft The rear brakes are not locked but close. Truck now running rough.
ANSWER : You will have to bleed the brakes from the farthest location all the way to the master cylinder. There is still air in the lines causing the issue. Check the vibrations on the vehicle to see if the engine mounts are damaged or if the brakes are not releasing causing the engine to run harder than normal to overcome the braking force. If you need further assistance with your vehicle’s brake system, then seek out a professional, such as one from Your Mechanic, to help you.

EPC light on 2004 Jetta. Code said brake switch faulty, but brakes lights worked. Replaced brake switch, now no brake lights.
ANSWER : Hi there. The first thing that pops in my mind beyond of what you have listed is perhaps the electrical harness attached to the brake switch. Perhaps the harness itself is damaged or you have an exposed wire, loose ground wire somewhere. You might want to have a professional mobile mechanic come to your location and complete a brake lights not working inspection to help you diagnose this issue.