What is problem when rear wheel is leaking brake fluid ?

1. If there is a substantial fluid eruption, there are air bubbles still trapped in the system. You must repeat the bleeding procedure to remove that air. A modest disturbance in the fluid returning to the reservoir indicates a properly bled brakesystem.
   

   How To: Bleed Your Brakes - Feature - Car and Driver

   www.caranddriver.com/.../how-to-bleed-your-brakes-feature Car and Driver

Feedback

How To: Bleed Your Brakes - Feature - Car and Driver

www.caranddriver.com > Features

Car and DriverIf there is a substantial fluid eruption, there are air bubbles still trapped in the system. You must repeat the bleeding procedure to remove that air. A modest disturbance in the fluid returning to the reservoir indicates a properly bled brake system.

How to Bleed Brakes - Tips on Bleeding Brakes

The leak could be due to a leaking brake line in the rear or a leaking brake cylinder. Have the car inspected for the leak by a reputable garage. The car will need to be towed, since it has no brakes.
If you do your own work, refill the master cylinder. Have someone depress the brake peddle while you look under the car for the leak.

If it is clear water, and its leaking onto the ground, and you are running the ac, its condensation from the ac.

The leak probably let air into the line. You will have to bleed the brakes.

I have the same truck! You could have a leaking wheel cylinder. Look at the brake drum on the driver rear and see if its wet. also check your brake fluid level. If you are leaking you will be low.
Wheel cyl's are not super hard to do, just make sure you do everything and both sides. also do one side at a time so you can use the other side for reference when putting it all back together.

good chance you have a leak in your break line. easy way to check is have someone press break while you look under the car. best position is just behind wheel look for fluid to spray out you will see a break line from the axel area to your wheel gl

Brake lines by rear door on drivers side are a common failure point. lines under door failing can cause a total brake failure. Just replace and bleed the lines.

It's a sealed system, so it's got to be going somewhere, leaking somewhere (or boiling off from severe braking operations over and over). Since you likely haven't experienced extreme braking, it must be leaking somewhere.
You will have to trace all your brake lines from the master cylinder to each wheel to check for any sign of leaking. Front calipers are easy to spot leaks when they leak. If you have drum brakes on the rear, you may need to pull off the drum to check the wheel brake cylinders. Peel back the rubber boot on each end of the wheel cylinder and look for any fluid leaks there.
Another place to check is at the back of the master cylinder. If a seal is bad there, it has been known to leak fluid inside the car, under the dash. Feel around the carpet under and behind the brake pedal for any wetness. If you find brake fluid there, you will need the master cylinder replaced or rebuilt.
Hope you find the problem. Don't forget to check the ABS system and brake lines, too.

1- New master cylinders could also fail, possibly due to bad quality replacement parts or maybe even just a factory fault on a good quality master cylinder.

2- If you had blown a rear wheel cylinder, you most deffinatly should still have had a form of front brakes. the reason for this is as follows... For this very saftey meassure manufactures design the container for the brake fluid supplying the master cylinder in two internally, so this would mean that if you where to drain all the brake fluid through the rear wheel cylinders an acceptable amount of brake fluid should still remain within the one compartment of the reservoir for the front brakes to still opperate.

3- Leaking rear wheel cylinders should have been noticed by the technician who installed the master cylinder, the reason for this is because the brake fluid would have had to be bled through the system at each wheel. even though it would have been performed from the back of the wheel one would expect the technician to notice the brake fluid dripping out behind the brake drum.

I hope the above is of assistance to you.

Regards.

by stating that your pedal sinks to the floor, you leave 3 options open 1.) the master cylinder seal is bypassing allowing the fluid to bleed by the proper correction is to rebuild the master cylinder.
2. One of your drum brakes has a wheel cylinder that has failed causing a noticable behind the tire leak (most common) correction is to replace all brake hardware and wheel cylinder.
3. One of the brake lines is cracked,broken, inspect for leaks and replace with new line.
4. notice on disc brakes if a brake caliper fails (part that squeezes brake pads to rotor) you will have the same symptoms of a broken wheel cylinder, this would of gradually occured feeling a heavy pedal or pulsation.