Brake pedal goes to floor
 

Im having all kinds of brake problems. I have replaced a whole bunch of things and havnt got the problem fixed.

Replaced the master cylinder, both front brake hoses, both calipers, both rear wheel cylinders, all brake pads.

The problem Im getting is my brake pedal goes to the floor when stopping. As soon as I start pushing on it I can feel some resistance on it wanting to stop but I need to push it to the floor to get it to stop harder.

I pump up my brakes with the truck running and hold the pedal in and it slowly goes to the floor.

I drove today after replacing my rear brakes and cylinders and now my front brakes smell of burnt brakes bad, maybe because my rear pads are not adjusted properly. I know how to adjust the pads but im not sure how far to go with adjusting it. Anyone got advice on how to do it properly so its not relying so much on the front pads for stopping.

My ABS light comes on randomly, could the problem just be a bad ABS unit? Or would something else also make the light come on. The light dont come on all the time either.

Some say the master cylinder is bad and some say the booster is bad, but wouldnt a bad booster just make the pedal hard and not so spongy?

I really want to get this fixed im tired of running around trying to figure it out...

To adjust the rear brakes jack up the rear wheels clear of the pavement. Make sure the parking brake is fully off. Rotate the wheel by hand to make sure it turns freely. Adjust the star wheel and keep rotating the wheel by hand untill you feel a slight drag. Stop adjusting and do the other one the same. That should do it.
If you still have excessive pedal travel then I would bleed the system again to make sure all the air is out. The proper sequence for bleeding is right rear, left rear, RABS module, right front, left front.

You either got a bad master cylinder off the shelf or, as Lazy K said you still have air in the system. Follow his sequence for bleeding the brakes to make sure it isn't air in the system.

The ABS light has nothing to do with how the brake pedal feels. All it does is keep the brakes from locking up when in a panic stop. If the light is coming on then there is a seperate problem with that system.

Chris

Today the pedal has been sticking to the floor when I hit the brakes, and have to use my foot to pull the pedal back up. I still have good stopping power.

I unhooked the vacuum to the pedal and had a hard pedal, hooked it back up and the pedal goes to the floor.

I had the same problem on my 96 f250 couldnt find out what was wrong. I even changed the master twice thinking i got a bad one. but i did end up talking to another mechanic and found that theres a Rabbes valve or how ever you spell it that would make this happen its located on the driver frame rail like under the door area maybe little before. Cost me like 150 new but I get it for cost. It has something to do with the ABS . after i changed it never had a problem sense real easy to install.

Classic signs of air in the system.

^^What he said^^

If you are doing this by yourself, it's difficult, but do-able. If you can have someone help, it makes it a lot easier. You may also want to take a minute and be sure there is no bleeder vavle seeping fluid. I've seen several RE-MAN units do this when I have replaced calipers. Do the step-by-step process Lazy-K mentioned and you should be ok.

I think that even with help, I had to do the entire truck 6-8 times before I got all the air out.

Let us know what happens

I would say once you have all the air out, do it a couple more tires for good measure (it can't hurt). The last couple times, I usually have the person helping me push the pedal extra hard to push the fluid out with velocity, just in case there is a pesky bubble caught up on something.

I do my breaks in the order LazyK mentioned above, because that's how everyone says to do it, but I never understood why. Anyone have some insight on that?

furthest from the master cylinder to closest.

http://www.talksox.com/forum/attachm...s-facepalm.gif I guess I should rephrase the question. I know that order of bleeding is going from furthest to closest. What I want to know is why that makes a difference.

once i removed the RABS assembly out of the brake system, the sinking pedal feeling magically disappeared on my 88

tjc has a point with the RABS. Look to see if there is fluid seeping in the center of the unit. I know you can remove it and dissamble it if neccessary. Had a buddy that his wasn't working correctly and it was rusted inside and the gasket was bad. Allowing for rust to form inside the unit. Could be a good time to check it out.

Is the RABS fixable, or just a trip to the junkyard?

yes, fixable, also can grab one at the junk yard or buy a new one for I think $100-150

How can it be repaired? I got a new booster and master if it still gotta bleed brakes in the morning, We will see how it works out.


I used a vacuum gauge on my system and pumped it up to 10 and it slowly bled off.