I keep pressure on the pedal it will slowly go down to the carpet

I would suspect there is air in the lines. These guides can help you fix it.

https://youtu.be/w7gUsj2us0U

and

https://youtu.be/WDxvEQrMkBg

and

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

Please run down these guides and report back.

We are unable to bleed the brakes after front caliper and brake shoes replacement. After bleeding all wheels engine off with seemingly improving pedal, when engine started there is no brake pedal at all. Master cylinder may have run dry during procedure. Is master cylinder bleedable? System seems to be drawing in air, can't see where or how. We've even tried to bleed the brakes with the engine running thinking the vacuum assist is the problem. Having bled brakes a number of times over the years I'm really stumped as what i'm doing wrong. 2000 Jeep Cherokee. p.s. brake pedal travel doesn't feel right during procedure feels a small hitch during full travel about half way.

When replacing the front pads, did you force the fluid from the caliper piston back into the master cylender or did you bleed it out at the caliper's bleeder valve? Also, are the rear brakes properly adjusted? Finally, the glitch you feel is most likely the brake light switch.

As far as bleeding the master cylender, fill it, loosten the brake lines where they attach to it, and then allow the pedal to hit the floor. Tighten the hoses then release the brake pedal until all air is out.

problem is pedal at top after starting pedal goes to the floor.

Good morning,

I attached a guide for you of the possibilities of what the failure could be.

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

It sounds like air in the system or a master cylinder that has failed.

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

Any recent work done?

Roy

Replaced front brake pads and calibers and bled, but now it won't get a pedal.

Good morning,

Why did you replace the calipers?

Did you pressure bleed the system or use someone to press the pedal? A lot of times, pushing the pedal to the floor damages the seals inside the master cylinder and there will be no pressure build-up.

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

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

Roy

I was driving home earlier today and when I press down on the brake peddle I heard a loud pop and my brake peddle lost all pressure and went all the way down to the floor. I would have caused this and what can I do to fix this?

If you didn't find any leaks to the brake lines, calipers, or wheel cylinders, chances are the master cylinder is bad. NOTE: Check the brake fluid in the master cylinder. If you have a leak, it will be low.

We changed the front brakes, rotors, calipers also master cylinder. We also, bled all 4 tires..our brakes still goto floor..what could it be?

Did you bench bleed the master cylinder before you installed it.

Yes my brother in law did but having same issues. .

Are you getting any air from the brakes when you bleed them? If you are you will need to bleed the system at the master cylinder. Loosen the brake line at the master and have someone to press the brake pedal down and hold it. It you have air at this point you will need to keep bleeding.
If you are not getting air anywhere in your lines and the pedal is going down you are losing pressure somewhere. look for brake line leaks and check your rear brakes and see if the rear wheel cylinders are leaking. If they are they will need to be repalced. If you check all of this and you are still have no pedal you may have a faulty master cylinder.

1991 Cherokee Brake peddle goes to the floor when engine is started?

When you replaced the master did you bench bleed it? If not this is your problem. Here are two guides to help you with the problem:

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

and

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

Please run down these guides and report back.

Cheers, Ken

The master was bench bled, and I did this sequence when bleeding the lines; right back, left back, right front and left front, getting absolutely no air from the lines. Cannot find any fluid nor vacuum leaks. Frustrating!

No problem lets isolate the master from the wheels, gently use three vise grips with cardboard to protect the rubber brake hoses and close them off (gently). Next check the brake pedal if it goes to the floor you know it the master if you have good pedal the problem is at the wheels. Truck have ABS?

Yes, it has the ABS with the ADA pump (I think that's what it is called).

I clamped the lines off and the pedal was solid as a rock, I released the back lines first and the pedal dropped a small amount, right front a little more and left front back to the floor. Evidently either as much as I have bled them it still is not enough or I have got new bad calipers! I will post which way it ends. Thank you for the help!

New driver side caliper and brake hose. New rear brake hose. New driver and passenger rear wheel cylinders. New master cylinder and new brake booster. New pads and shoes. While engine is off brake pedal will pump up like it should. With the engine running the pedal has no resistance and will go all the way to the floor. Putting the vehicle in gear and driving you can barely touch the brake pedal and get brakes, but even pushed all the way to the floor does not stop the vehicle like it should. Have bled the brakes with some one helping pump the pedal as I opened the bleeder valves. Bled the brakes with pressure bleeder. Even let the brake system gravity bleed for four hours, consistently checking the reservoir and filling back up as necessary. I had some brake pedal resistance after the gravity bleed. But after driving through about three tanks of gas I have no resistance again on the brake pedal. Absolutely lost. Any assistance would be greatly appreciated.

Only four items would cause this issue. Air still trapped in the system, replacement master cylinder has a problem the rear drums are adjusted too slack or one of the calipers is hung and the piston is floating.

Double check your rear shoe/drum adjustment. If those are even a bit loose you get a bad pedal. Check that the calipers are able to slide and that they are actually working.

If those are okay. I would pull the master off, bench bleed it carefully. Then reinstall and bleed the brakes in sequence RR, LR, RF, LF. Bleed about a pint through at each wheel. Pressure bleed if possible.

Nice work isolating the problem. Check the caliper slides because if they are seized it will cause this as well. Also, make sure the brake bleeder is on the top of the calipers. If you have them on the wrong side the bleeder will be at the bottom.

I have had an on going problem with the brakes, I changed master cylinder, power booster shoes and pads and still the brakes are not great. No matter how slow I am going and how hard I press the pedal they will not lock, when going down a steep incline they have a hard time slowing the car down. Yesterday when pulling out of the garage the rear wheels locked when I just touched the pedal. I have been told to check the proportioning valve, but I thought this was just for emergency braking. Any info would be appreciated.

The Proportioning valve is designed to keep the rear brakes at a lower pressure than the front, and also to provide pressure to either the front or rear, if one system fails. If the pressure in the front drops too low, the rear brakes will take the full force of the braking action (and lock up). Some are also designed to reduce the amount of air let back into the system if a leak should occur. Cherokees are a very heavy vehicle, and the braking system on the older ones were hard to lock up. With the recent problem of having the rear brakes lock up on you, I would suggest that you very carefully check all of your lines for pinhole leaks. You can also upgrade your rotors to drilled and/or slotted, to help to improve the performance. Also check for proper adjustment of the rear brakes and make sure all caliper/shoe contact points are smooth, well polished, and lubricated with a grease designed for brake systems. Use 120 grit sand paper to break any glaze on rotors, or have them turned if they show wear.