I just replaced my calipers and flushed out and replaced my brake fluid. After the install and bleeding the brakes. The peddle was really soft. I drove the car and it will stop. Just not really well. I then bled the brakes again. Same result. I read that I may have air in the ABS module. And to try and activate the ABS. So I got on a dirt road and a asphalt road with dirt on it and lock them up and the Low Traction light came on. The pedal still felt the same. I got the Low Traction light to come on 6 times. Same soft pedal.

I have no lights on in the cluster. No ABS light. No check engine light. Any other reason I could have the pedal drop so low before engaging the brakes?

Any info is appreciated.

 

you need to bleed again AFTER doing the "lockup on dirt road" move to purge the ABS block of air, that air bubble would now have moved into the lines, Be sure and NEVER let the Master Cylinder run dry when bleeding the whole system like this.

What bleeding method are you using? We have to make sure nothing your doing is just sucking air back in thru the bleeder screw.

 

I did the pressure method to start. I did also do the old school pump the breaks and hold then bleed option as well. The Master Cylinder did run dry. I should have just pumped the new fluid in to push out the old fluid. But I honestly have never done breaks other than changing pads. I have done so many other things with cars. Just never bled breaks or changed fluid.

 

I've heard people say the pressure method introduces air into the system, letting the MC run dry means you DEFINITELY got air in the lines. the method I used was a 2 man job when I TOTALLY flushed my system, I went to the parts store and bought a a clear hose (forgot the size) from the HELP aisle at advance it was just the right size for the bleeder screw so I attached the hose to the bleeder screw and ran it down into a empty powerade bottle, I made sure the MC was full (and checked it every 5-6 pumps of the brakes, topping off as needed) and I simply opened the bleeder screw and had my friend pump the pedal till fresh fluid was coming out (once you get enough old fluid into the bottle it prevents air from getting sucked in at the bleeder screw), once fresh fluid was coming out I closed the bleeder, had him pump the brakes and did just a quick open/close on the bleeder screw (like the classic method), then repeat at all wheels.

 

I did all that. I did the old school pump and hold the break then bleed the locations. I did the pressure method first. Then moved onto the old school way.

 

One thing I didnt do. I didnt bleed the brakes after I got the ABS to engage. But if thats the case and it spits the air out of its unit into the brake line. I should build pressure via pumping the pedal. In my case the pedal stays soft.

If air is coming in through bleeder, would my pedal be soft?

 

So I have bled the brakes quite a bit more. Roughly 3liters worth of fluid. Still no brakes. Pedal gets solid but once you turn the ignition on, I lose the pedal. I feel the bleeder screws are to lose at a 1/4 turn to bleed them. Maybe they're correct. I don't know. Any other idea's from anyone?

Any opinions are appreciated. Id like to try and figure it out before going to the dealer and them telling me to replace things I may not need. My local dealer isn't very good at they're job.

 

Motive Power Bleeder, that is all you need. I have been using this method for 5 years now, bleeding my brakes 7-8 times already (track days) and have never had an issue. I bleed my brakes by myself with no assistance. I use regular bleed screws, have had my calipers off many times, have all braided SS lines, and had to get a new master once due to a crack in the original plastic.

I feel this is the best way to bleed brakes period! it takes me an hour or so, but it is worth it in the end. for every day driving i just use the Valvoline DOT 3/4 from Autozone, so no super fluid here.

 

I have that motive bleeder. It doesnt seem to put as much pressure as the old school pump pump pump pump/hold method.

What psi and you setting yours to? I feel I read to only go to 15psi. At that kind of psi I have very little pressure in my lines.

 

Did you bench bleed the master? If not, you might need to. If your linkage does not go from completely out to completely in there could be air in there.

 

dezertrat: bleeding the brakes has nothing to do with pressure. the purpose of bleeding the brakes is to push any air in the system to the calipers and out the caliper bleeder screw. so you need minimal pressure. when you power bleed the brakes such as with a motive power bleeder or garden sprayer, you're pressurizing the master cylinder reservoir only to 5-10 psi. you don't want to go more than that because the plastic reservoir isn't designed to be pressurized to any great amount and whatever cap you are using will either pop off or just leak after ~15 psi. so when you power bleed or pressurize the master cyl reservoir you can maintain a constant fairly fast moving flow of brake fluid down the system pushing air, this is what's important, and you can observe that by watching the flow of brake fluid out the caliper bleeder.
the problem with pumping the pedal and holding it down then cracking the bleeder, is you only move an ounce of fluid at a time- when you do it how much fluid comes out when you crack the caliper bleeder? so now think what happens. you have the reservoir at the highest point in the system, any air in lines that has any vertical run to it the air bubbles will work their way upward. so you move an ounce of fluid at a time, and an air bubble moves a little way down and toward the caliper in the brake line but then you stop and the air bubble makes it's way backward because the line has a vertical rise to it, so you never move the air out with this method. the only way pumping the pedal is worth doing is if you have earl's solo bleeders at the calipers which allow you to crack them then you can pump the pedal like mad and move fluid through the system fast enough.

the master cyl reservoir holds enough fluid when full to simply pressurize it with air and force that volume of fluid down and out the brake system. you stop bleeding when the master cyl reservoir is around 1/4 full, then refill, repressurize, reopen bleeder screw.

fwiw i've had the entire abs module out of my truck repairing all the brake hard lines. i've drained that abs module on my bench, reinstalled it along with all new hard lines on my truck and all new calipers, all completely full of air. i used the power bleeder and had zero problems. there is a section in gm service manuals that states if there are brake problems that the abs module may need to be activated and cycled to get air out of that but i don't believe it. the hydraulic part of the abs module is quite simple and is open most of the time to allow fluid to flow through it, so if you really look into it there is nearly zero risk of the abs module being able to trap air and cause problems.

your only other problem if you don't have a fluid leak, is the master cylinder is leaking internally and not holding pressure or you have a lot of air in the master. this you can verify with engine off and vacuum booster depleted, pump brake pedal till it firms up then press down hard and see if the pedal holds over a minute. if it slowly makes its way downward with the same amount of pressure then you need a new master cylinder. even if there's air in the system, the pedal will go down farther but should hold at some point and the system should hold pressure and the brake pedal should not drop to the floor. if you can't get the pedal to firm up then you most likely have a lot of air in the system. most likely you need to re-bleed the system and i would use 2 quarts of fluid. fill the master completely then pressurize it. run 1 reservoir's fluid worth out each front caliper. run 2 reservoirs worth doing the first rear caliper, then 1 more reservoir's worth doing the other rear caliper. you power bleed this way and have a steady stream of fluid out each caliper you won't have any air in the system.

 

I have ran 3 liters of fluid through. I want to look into the testing the master cylinder. When I did the old school pumping and holding method. I got quite a bit of fluid to flow out. When I do the motive pressure system, It seems that barely anything comes out. So its hard to tell if air is even coming out. Their may even be half the bleeder hose filled. I mean half like it isnt filling the whole house on its way down. Just a little bit of drainage.

So your saying with the pressure system to start with the front calipers?

Also the pedal got stiff when bleeding. But once the car was started it lost all its pressure.

BTW I greatly appreciate the feedback.

 

it sounds like you have a bad master,
if you had dark colored brake fluid in the master reservoir, and the white plastic is coated with slime and floaties, and the brake system has never been serviced, then chances are the o-rings in the master cyl are shot.

the brake system is designed around an average 100 lbs of force from driver foot against brake pedal. with vacuum assist the brake booster boosts that force which then will cause a bad master cylinder to manifest itself.

the order of bleeding which caliper first really doesn't matter. i mentioned what i did so it's orderly and saves you on fluid. the only concern is getting air out the system, the abs block is where everything splits so once brake fluid is in there it doesn't matter caliper or order you use to bleed.
why the power bleeder doesn't give you significant fluid flow out the bleeder i don't know. when i did my truck one of my rear calipers would shoot fluid out 5 feet from the bleeder with 5-10 psi of pressure in the master cyl reservoir, but less than a foot from the other caliper. for you my only thought is your abs block has contamination in it or one of the pistons in it are partially closed and stuck hindering flow, but as long as fluid flows out you should be fine. brake fluid that's neglected and never changed can get real nasty and could end up hurting the abs block, but it's unlikely. it would have to cause a piston in the abs block to stick closed, and that would only happen when abs kicks in which is rare.
the fact the hose off the bleeder does not fill completely doesn't matter, it depends on how you lay the hose and how fast fluid flows out. also be aware the hose you attach to the bleeder can have air seep in where it fits on the bleeder, causing bubbles in the fluid and make it look like air is coming out from inside the caliper when it really isn't.

 

Do the bleeder screws need to face up or down on the front? And do the rears matter since they're on the back of the caliper?

 

If there is only 1 bleader per caliper, yes they have to face up. Start at the pass side rear, then drivers rear, then the pass front, and finish with drivers front.

 

Normally if the master cylinder is bad, when stopped, your pedal will be firm but slowly go to the floor as the fluid leaks thru the seal.

The master cylinder can have a large bubble in it that is difficult to bleed out.

Yes the bleeders should always be up. If they are not you get a bubble high in the caliper that you cannot bleed out.

Another item that can cause a soft peddle is a bad flex hose. When they get old they can stretch under pressure causing a soft peddle. Normally if you have this problem they will fail completely fairly soon. How old are your flex lines and what condition are they in?

Good luck.

 

The bleeder screws should always on any car face up.