Brake pedal sinks?

Thanks for the video, yes it does look like the brake master is bad, but I would check the caliper slides as well because the caliper piston will be forces back into the caliper housing causing the pedal to go to the floor, here is a guide to help:

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

You can tell for sure if you use 3 pairs of vise grips and gently close off the brake flex hoses, if the pedal still drops the brake master is bad, this video will show you how to bleed the brake master before installation:

https://www.youtube.com/watch?v=WDxvEQrMkBg

Please go over these guides and get back to us.

Thanks. Never heard of this vise grip hack. You mean use the vise grips on 3 of the 4 wheels and kind of close the hoses? I will check the calipers first for sure. Also, this has rear drums, is it possible that if brakes are worn in the rear it can cause that? Even though the fronts are good?

So lifted the car on all 4. No fluid leaks around any of the wheels or lines. Removed the hose from intake to booster. Cleaned it with brake cleaner to clean any debris from the check valve. Brake pedal gets tight when pumping it while off, the once car started it sinks. Also, when i removed the hose from the booster it gave a good vacuum sound. Placed parking brake on and neither rear wheel move so that's good. Will see about bleeding it first to see if that makes a difference, but no matter how much air there is no way it can lead for it to be this bad as to extremely difficult to stop, whoever had it was driving it for sure. So, if bleeding is okay, master must be bad.

More findings. So after i lifted the car i put it in gear to see what happens and the left wheel was wobbling so bad i thought maybe the wheel bearing is bad. Removed it and it looks like someone just installed new rotors and pads. So i removed the caliper and pressed the brakes and it didnt move, not sure if its a caliper issue or if they opened the lines when they did the work. While the wheel is turning when in drive and while i press the brakes the wheels keep moving have zero brakes.

Check this out please.

No that is not normal, it looks like the caliper can be sucking air back into the system when the brake pedal is let off. I would do the vise grip trick but, on all wheels, to see if the problem is with the calipers or brake master.

I will. So, pinch the lines lightly with 3 if them and see.

Yep, this way you can isolate the problem.

pedal still drops no matter what, bled all 4, sometimes with brake pressed the front left and rear right both can move freely, not until you pump the pedal few times when all 4 do hold.

Yep, that would be a bad master cylinder or you have air stuck in the ABS module.

https://www.youtube.com/watch?v=nQRnKyVyMuQ

Let us know what you find.

Changed it but it's still mushy. I out the car in drive and the driver aide wheel moves then i can only stop it if i pump the brake pedal.

Did you use a scan tool to open the ABS module internal valves? Also, did you try the vise grip trick?


https://www.youtube.com/watch?v=nQRnKyVyMuQ

Please go over this video.

No didn't try via scanner, I will try it. Oh, shoot I only did the vise grip on one I forgot, let me try it on all 4.

Did you mean to yse 3 grips on 3 wheels or 3 vise grips on one wheel hose?

The idea is the block all four wheels to isolate the brake system into halves.

Oh, i understand now. And then remove the vise grip once at a time to see which wheel has the issue.

Yep, sounds good, did you check the caliper slides to make sure one was not frozen?

can't be frozen if the wheels are moving, correct? I put in gear and driver side moves and if I hold it passenger does. Also, weird thing I have seen on several cars before, even if you leave the gear in neutral after you put it in drive the wheel keeps moving...

So, i got me a set of these in the picture instead of the vise grips. Once i blocked all 4 pedal gotten better, removed one at a time and when i did it to one of the rears all the pressure went there and i saw it leaking, removed the drum and holy crap lol. That doesn't look good. Leaking and nothing left on the shoes.

Wow, that is not good, it looks like you found the problem.

I am replacing both sides with all new stuff.