1999 brakes pushed all the way to the floor don't work, and there is fluid leaking on drivers side rear

catastrophic failure , DO NOT DRIVE
so find leak, see leak location, that is BAD.
MC (master cylinder)
or slaves (calipers or drum cylinders.
or hoses. (any)
pipes, (aka, hard lines)
junctions.
aBS?

why not post source of leak, or better photos.
or better yet, call a mech. for help .

floor, floor of cab, floor of garage, just a tiny hint on floor
and what 4 corners of car. inside or outside.
,fluid can leak down both sides of any MC

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.

AT FIRST GLANCE I WOULD BE LOOKING @ BRAKE FLUID CHECK LEVAL AND REAR WHEEL CYLNDERS MAY BE LEAKING, OR MASTER CYLNDER BYPASSING

Hi Chris, The brake system is basically very simple. If you have duel braking on your vehicle, the usual method is having two brakes operate on the front with for example the left rear and the other system will also operate two front and the right rear. This type of system will have two calipers on each of the front wheels. The tandem system works in a slightly different way, having the forward part of the cylinder pressurizing the rear brakes and the rear part of the cylinder pressurizing the front. I think under the circumstances you are describing, I would have a friend sit inside and pump the brakes repeatedly until the system becomes pressurized (maybe twenty thirty times of pumping the brake pedal) and then ask him or her to keep it pushed firmly down until you find out where its leaking. The amount of brake fluid you report having been sed would indecate a severe leakage. Check the lower parts of the rear wheels for signs of leaking wheel cylinders and then dito for the front wheels. Any signs of wetness at these areas and along the brake system (the plumbing or pipe work) will indicate where the leakage is. If you cannot identify a wheel which is leaking, carefully inspect around and blow the master cylinder and if this no sign go along the fluid lines, taking special note of where the damaged pipe was repaired. If there is a blockage in the line, air may be trapped at that point causing difficulty in pressurizing. Once the place of leakage has been identified it must be attended to before bleeding the system. When bleeding, begin with the wheel furthest from the master cylinder, and work your way back to the master cylinder one wheel at a time, until you reach the closest.Keep in mind that you may find it required to pump the pedal many many times before opening the bleed nipple.Regards John

Hi oakleafwoodw, sounds as if the brake master cylinder has busted a seal allowing the brake fluid to leak by cylinder when you push the brake pedal giving you no or very little pedal pressure....it is located under the hood on the drivers side firewall, you will see all the brake lines attached to it , remove those and the two bolts holding it on,take it with you to auto parts store for a rebuilt one , they will keep your core for rebuilding, other wise you pay a core charge., verify that they have the one you need before hand, get a quart of dot 4 brake fluid, hook it up, and bleed air from the brake lines starting with wheel cylinders in this order Right rear......left rear.....right front.....left front...making sure to keep fluid level topped off in the master cylinder during the whole bleeding process or you will pump air into lines....OK!! caution: you should not drive it until you have good brakes!! you said they still work but if you had to stop suddenly ,it won't do it.

Is it water or brake fluid. Water could be a windscreen leak or leaves have got through the outside grille of the vent, blocking the drain, so when it rains the piping is full of water. As you go around corners the water leaks into the cab.

If it is brake fluid, you have a leak in the master cylinder which allows fluid to leak down the push rod, onto the pedal and into your carpet. If you are not having to top up your brake fluid it is not likely to be the problem.

After you put the fluid in the brakes start your blazer keep it in park or in nutral with the parking brake on and then push as hard as you can on the brake peddle using the steering wheel as leverage.This should pop any brake line that is leaking a little bit but not enough to pop any good lines.If the peddle slowly goes to the floor check undernieth the vehicle for any signs of leaking.If no signs of leaking look under the hood where the brake master cylinder is and check for any leaking around the mounting surface.If no leaks there check inside the vehicle where the brake peddle goes threw to the master cylinder for leaks on the inside,this does happen from time to time.

if you found a leak, was is an air leak or a fluid leak? Since you state the rear brakes were leaking I assume its brake fluid. You must clean away all fluid and have the car securely supported in the air to see were the leak is coming from with someone else pressing on the brake pedal while you watch underneath the area with the problem

push the pedal and see if it goes to the floor slowly or fast, if so,some thing like this i would lay on the ground in the back and have some one push the pedlal and hold it, look for fluid, like wet spot near the wheels first ( i have seen wheel cylinder go bad but not leak alot at one time so keep that in mind too) and make your way to the front on the driver side inside of the fram.i dont think its the master cylinder but see if you can see a wet spot at the bottom of the master and the booster( i seen masters not leak as will )

leaks will make the ABS lite come on

Check to see if the brake line is leaking. If it’s not , it is probably the slave cylinder. Remove the wheel, take the brake drum off and you should see the cylinder. If it is a disk brake. You have the inside brake pad plunge seal leaking. Sorry I don’t remember if the brakes are disk or drum, and I don’t have my books close. Either way it is a relatively easy fix. Parts are readily available at the auto parts store.