I have a 2003 Chevy suburban. I'm stumped On this issue with the brakes, now when I 1st encountered this I replaced brake lines Just 2 That were busted Then bled the system Just find out master cylinder was bad Replace the master cylinder twice blend system again Still pedal goes to the floor,bled system number of time manually and with the machine still pedal goes to the floor then replaced the 2 rear rubber hoses bled the brakes again,now here's where it gets weird pedal is spongy but it holds for the day then let it sit over night back to the floor just replaced the brake booster still no fix if anyone can help let me know

  • Can you please edit that wall of words into digestible sentences and paragraphs with proper punctuation.
    – Alaska Man
    Commented Dec 30, 2020 at 18:03

5 Answers 5


Welcome to MVM & Repair!

The problem you're experiencing is caused by one of three things:

  1. Brake pads are missing, brake disks are missing or brakes shoes (inside the brake drums) are not adjusted properly. Make sure the brake pads are in the right place and that there's not a huge hap between the pad's surface and the brake disk. If the rear brakes are drums, make sure the brake shoes are adjusted properly. You can test this very easily by pulling up the hand brake. If you feel no resistance, adjust the shoes, by taking off the drum and turning the self-adjuster.
  2. There is air in the system. Pretty straight-forward. Bleed the brakes (preferibly starting with the brake that is the furthest from the master cylinder, which will be the rear right on left hand drive vehicles). Loosen the bleed nipple, slowly press the brake, tighten the nipple, release the brake, repeat. Make sure there is sufficient fluid in the resevoir.
  3. There is a leak in the system or a bleed nipple is not tightened properly. Replace the part that's leaking and bleed the brakes until there's no air in the system.

Sounds to me like you have air seeping into the hydraulic lines overnight you should check every fitting maticulously don't try and rush brake jobs, have you checked all cylinders for leaks and does the car have abs if yes it needs special bleeding via computor to flush the pump.

  • I have checked for leaks and there is none, I don't know what you mean by cylinders cuz I have disc brakes all around
    – Flippin Ed
    Commented Dec 28, 2020 at 13:31

In conjunction with the previous answers, you may need to bleed the ABS system. This is usually done with a scan tool.

  • Did that about 3 time during the bleeding process
    – Flippin Ed
    Commented Dec 28, 2020 at 13:25
  • If there are no leaks, there is air or leaking seals. There are cylinders on disc brake systems in the calipers. With a small screwdriver pull the rubber seal around the piston out a little all the way around the cylinder. If you see moisture, you have a leak. Also be sure to bench bleed the master cylinder. Of there are no leaks anywhere including the cylinders and there is no air anywhere in the system you probably have a bad or wrong master cylinder.
    – Jupiter
    Commented Dec 28, 2020 at 22:14

Check Rubber(connects on shock column) and Steel(long feed goes under car) brake lines Proportioning valve Caliper pistons seals ABS modulator


How to check :

  • Check if there is anything missing.
  • Check if the adjuster at a good position on your brake booster (the new one usually have a slight difference)
  • Bleed the master cylinder.
  • Bleed the brake from all tires.

The most overlooked is to bleed the master cylinder because everyone just focuses on the tire.

How to bleed your brakes instruction can be found here:

And don't forget to tighten back your bleed bolt, if the bleed bolt is leaking you will likely get the same result.

  • 1
    How do you bleed the brake from the tires? I find it easier to use the bleed nipple on the brake caliper.
    – Solar Mike
    Commented Dec 28, 2020 at 7:33
  • yes, it is a brake caliper. Commented Dec 28, 2020 at 7:39

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