brake pedal to floor-brake light on

[hammer2]

2000 grand prix. driving to work and at red light i hit brakes. seemed normal at first, but as i applied them more the pedal just kept going to floor with no increase in braking action. once it hit floor, by pushing real hard, I did get some more brake and stopped. I pulled into a development and tested things out and then limped home about a mile and got different car to come to work. I also noticed the brake light is on. I haven't had a chance to do any investigation, but was just wondering what exactly the sensor monitors? Is it only fluid level? Does this sound like a burst brake line? if you burst line, say in front, would still have rear brakes? I thought that there were two systems, but didn't know if they were split front/rear.

[mechanic1980]

broken brake line or bad master cylinder or wheel cylinders just put some fluid in the resevoir and have someone pump the pedal and see where it comes out if nothing comes out but the fluid keeps dissappearing its the master for sure

[tblake]

GP's have read disc so no wheel cylinders.

Your car is a diagnal split so if one line bursts, the opposite side of the burst line and the one diagnal from it will still have brakes.

Better climb under there and see what happened.

[JonJon68]

I just had this happen about a year ago...My brake lines rusted out causing a massive loss of brake pressure coming to a stop. As stated before, don't let the master cylinder run dry and replace the brake line if it's not your master cylinder.

[hammer2]

OK, got home from work and had chance to look it over. master cylinder was low. filled it up and had wife pump brakes. no leaks seen from top. put front on ramps. had her pump. didn't see anything around either front wheel. then looked towards back and saw fluid dripping. put rear on ramps and found a leak. there are two lines that run under driver seat. they turn up in driver side rear wheel area and then they each connect to other lines. the line to driver side rear is very short line that then mounts to a bracket where the rubber line connects to it. The short line is the one that is leaking. My first thought was great, as this is easiest to change. But then looking at other lines, i think I really need to change several of them. probably the one that runs over to passenger side. the longs lines under seat don't look too great either. haven't had chance to look at all of them yet. but if one is rusted that badly, think any that show signs of rust should be replaced? should I get wire brush and scrape them off to see how bad the rust is and then replace any that have more than light surface rust? and if I need to replace the lines that connect to the ABS, will I be able to bleed them? or will i then have to take it to shop to have them bleed it?

[doctorhrdware]

When I had that happen to the brakes on my GP. I used a vacuum pump to bleed the brakes after I replace the bad brake line. I bleed the brakes until the fluid is clear and not black. I have not had any more problems since I fixed the brakes.

[hammer2]

got broken line out no problem. called advance auto. they only have straight lines that you have to bend and they will loan tool to bend. so go to pick one up. of course they don't have what I need. mine is 26" long with flare (bubble?) on the ends. one end is 3/16 and other is 1/4. that is the problem. guy had 30" line with 3/16 on each end, but didn't have an adapter to go to 1/4 on the one end. called dealer (chevy). first said they can get it, cost is $87!!! for a 26" line. thought maybe he had wrong line so called another dealer. this one said they only have unbent, unflared line?? any thoughts? think home depot or lowes would have an adapter? and I need to lose 4" of line somehow-given that it is only 26" and follows wheel well, losing 4" may be difficult. have to put in several extra bends in a line that is relatively short.

[doctorhrdware]

I know that you are not suppose to use a union compression fitting, but I did. I used a 3/16'' fitting. I did the brakes back in 08, it has held up just fine. I check the fitting regularly and make sure the fitting is tight and there is no leaks.

[hammer2]

well just did some research on the bubble flare. I can use my regular flare tool, but need some kind of arbor. need to find where i can get that. then i can cut the tube I bought (to 26"), put the old 1/4 nut on one end,make bubble flare and then bend. after practicing making flare on the piece I cut off of course. not real keen on using compression fitting. HVAC guy tried to put one on my furnace line right above burner-they are against code at all but even worse to put one right above burner. so any thoughts on where to get arbor for my flaring tool?