brake pedal goes to the floor

Hopefully someone can tell me something. It started around 2 weeks ago. I went to stop and the pedal started to feel squishy. I thought i was low on fluid. I checked the fluid and that was full, so I checked the brakes themselves. I replaced the front ones first being they only had 25% life left, I also bleed the front brakes until the old fluid was gone then refilled with new. The pedal was a little better, not to what it was when I first bought it.Then I replaced the rear shoes but I haven't bleed the rear system but the pedal hasn't gotten any better. There doesn't appear to be any leaks in the brake system so if anyone has a clue please tell me. Thank you in advance, Nick.

Did you let the MC reservoir get empty when trying to bleed?

Squishy pedal/pedal going to the floor and no leaks would indicate air in the system (fluids don't compress) or fluid bypassing in a bad MC.

Try bleeding the system again, RR, LR, PS, DS is the proper order. Oh, and before trying to bleed them make sure you have the rear shoes adjusted correctly. There should be a very slight drag when done right.

If you bled the brakes until the fluid was gone and then added new, did you get air in the system? You have to keep the reservoir filled. Also, normally you bleed the longest line first (back right).

Yes I adjusted the rear shoes properly and yes the reservoir was ran dry but I refilled it and bleed the again and then topped the fluid off.

lsc910 said:

Yes I adjusted the rear shoes properly and yes the reservoir was ran dry but I refilled it and bleed the again and then topped the fluid off.

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So bleed again starting right rear, left rear, passenger front, drivers front--if that doesn't do it replace the MC and bleed again. Winterbeater has posted on here his gravity bleed procedure, it works and you get to drink beer while doing it--win/win.

This should cover most that can go wrong with brakes:

So, #1, you make sure there are no signs of leakage. That means no use of brake fluid from the reservoir. And no wetness on the inside of the rear wheels, brake lines, etc. If there is leakage, fix that first. #2, start vehicle and pump up brakes about 5-10 times and hole down pedal hard. If it goes down steadily, your master cylinder is shot - replace. Only two things can make the pedal go down. External leaks or internal master cylinder leaks. If it holds, and you still need to pump the brakes to make them work, either your rear brakes are way out of adjustment or you have air in the lines.

Adjusting rear brakes: They are supposed to be self adjusting, but that shit freezes up quite a bit, and even after I fixed mine, it seemed like the original self adjusting cable was made too long to adjust properly. The best is to take all this stuff apart (pull the drums off and lube it all up including dia-assembling the adjuster star wheel). But, thru the slots, you can tighten up the free play in the rear brakes which could be taking up more fluid than the stroke of the master cyl can displace. If you never did it before, you probably need to pop off the rear drums and look at everthing.

Bleeding brakes: The best way is the GRAVITY method. The only problem is it takes a lot of beer and you don't want to drive right after. (CAUTION: YOU MUST BE 21 TO BLEED YOUR BRAKES THIS WAY!) I use it whenever I replace brake cylinders or calipers, but mostly it's just to change the brake fluid, which I do whenever I change shoes or pads. Ideally you change brake fluid at least every other year. If you worked on old cars and saw rusty pistons, you'd know why, but people also say that old brake fluid boils and won't stop you right.

1.) Get the car in a position where you can open up the bleeders. I always like to break them loose with a 6 point socket being careful not to break them off. If you can, spray them with breakaway or similar a day before.)
2) Starting with the bleeder futhest away from the master (pass. rear), open it about 1 turn. You can put a little hose and cup on it if you want to keep the old fluid from running all over. Make SURE to keep the master cylinder topped off with fluid and DON'T let it get down to where air gets back into the master cyl. Let it flow this way until the fluid comes out of the bleeder clean. This will take at least 2 cups or so of brake fluid. Using gravity alone, you can drink 2 beers while topping off the master cylinder for the first corner. (CAUTION: Do not store brake fluid in beer cans or put beer into master cyinder. Drinking a little brake fluid however will probably not kill you. Beer in your brake lines might.) Snug up bleeder good when you're done.
3.) Proceed to drivers rear and repeat. It won't take as long because the long brake line has already been purged of the old fluid. So you have to drink your beer faster.
4.) Pass front. Drink even faster.
5.) Drivers front. Etc.

Patience can be substituted for beers, but that's no fun.

This prevents the rubber pieces from going any further than they are used to and self destructing.
"

From what you described you probably have a bad master. When you first had the issue of a weak pedal and had full fluid that was a good indicator. Was the fluid milky or just dirty. milky woud indicate air dispersed in the fluid not as a bubble in the line, you can bleed for days and still not get it right. if it gets like that it usually, but not always, means the master is bypassing internally and you need to replace it. dont be suprised if this leads to needing to replace a lot of the lines and possibly the distribution block.

not that air damages the line, they just tend to break when they come apart. another thing to check would be the rubber lines. look for any sign that they are expanding. A bubble or a crack in the outside of the rubber.