Hey guys, so I've got a 98 Blazer that has a brake problem I can't seem to pinpoint. It started earlier this week when driving to a buddies, brake light came up on dash, hit the brakes to stop and it went away. Got to buddies, parked for several hours and drove home no problems and no lights. The next day I take a 45 minute trip to friends, get there no problems go to drive home and brake light is up on dash and its been on since with the following conditions....
The brake pedal goes easily about 3/4 of the way to the floor before any braking power is felt.
If I stomp on the brake somewhat hard, I can feel some pressure in the pedal.
If the car is off I push the brakes in two or three times to get the pedal firm.
Nothing in the brake system has been opened recently.
I checked the brake fluid reservoir and found the front half of it empty.
I have checked all the lines I could see and didn't find any apparent leaks in the lines or at the caliper fittings. What do you guys think this could be? I was guessing a master cylinder but with half the fluid in the reservoir gone wouldn't this mean a leak somewhere? Maybe it is leaking into the booster?
Let me know what you guys think. Money is tight and I figured I would ask the forum before shelling out money for parts.
Thanks in advanced everyone.

 

I think your brake light will come on if your fluid is low, so top that off ASAP. Have your friend pulse your brake pedal (with engine on) and just go down the lines and see if there is any leakage.

Even a pinhole in a metal line will leave a noticeable dark spot on the ground.

 

you have a leak to the rear brakes, find the leak, fix, and bleed.

 

Wow thanks for the quick reply guys. I topped up that fluid as soon as I found it low. I was just under the truck with a flash light but I will have to have someone pump the brakes while I check it out. So when the front half of the reservoir is empty that means leak in the back, back half of the reservoir means leak in the front?
Also I forgot to add in the original post but now it seems that when braking somewhat hard (but not hard enough to lock the tires up) the ABS seems to want to kick in. Would this be caused by air getting in the system since my fluid was low in one half of the reservoir?

 

Cool was right. Leak in the metal line just behind the drivers side wheel. Will keep updated if anything exciting happens but it seems I'll just replace the line and be on my way (Knock on wood). Thanks guys

 

glad you found the issue.

Good luck with the fix. It might be easier to cut the original line in a clean spot and Double Flare in just that section.
On many cars that rear hard line is tough to get out