brake problem 90 taurus

[edsel]

put new pads on the front and shoes on the rear of my 90 taurus. with the engine off i have hard brade pedal. turn engine on and it goes to the floor. pump pump pump and the pedal stays on the floor. bench bled the master cylinder before putting it in and then bleed the brades rt rear rt front left rear and left front several times. ok did auto zone do me again with a bad master cylinder or do i keep bleeding until i get it right? thanks edsel....

[mwt47]

Not trying to sound like a smart butt but you bled them until the air quit coming out and you got a steady none bubbly stream of fluid?

Mike

[93atx-sho]

Try to bleed them again. Are you bleeding by yourself with like a one man pump or speed bleeders. I use speed bleeders my selF. If you r bleeding with a friend that will work to. But if by your self get the speed bleeders they work okay. Bleed from the (RIGHT REAR-LEFT REAR-RIGHT FRONT - LEFT FRONT). Keep reservoir full and cap on. You want to start at the wheel farthest from the master cylinder and work up....

[edsel]

bled t he brakes from the furthest point to the nearest to the master cylinder. bench bled the mc again and still no brakes? i am going to replace the mc again. the brakes just will not pump up. any ideas? could there still be air in the lines. this is the third time i bleed them?

[edsel]

replaced the master cylinder with no positive results. the pedal still goes to the floor with the engine on. i have pedal with the engine off but turn it on and down to the floor it goes and it will not pump up? i am going to check the action of the wheel cylinders when i return from work this week. i am going to bleed them again. not much else to check???? any ideas will be appreciated. thanks edsel.....

[tripletdaddy]

This is all a hunch. Ok, the only influence the engine has on the brake system is the vacuum. When there is no vac/eng off, brakes work. When eng on, vac is on. So, it sounds vac related. You don't have a vac leak you've found so far I assume. So, isn't there a check valve on or near the master cylinder ? Could it be not working, leaking? Check to see if you have correct vacuum at the master cylinder. Try with the engine on, pulling the vac hose to the master cyl and see what your brakes are like. If they work, I would lean toward the problem not in the brake system, but something to do with vac. When you do this, I assume you will be sure the pedal won't go to the floor.
Good luck

[shorod]

The brake system uses vacuum via the brake booster to reduce the amount of pedal force needed to apply the brakes. If you have a vacuum issue with the booster, you'll basically not notice a difference in the brake pedal feel between engine off and engine running. Also, this would be a pretty major vacuum leak, so the engine would run quite roughly. It sounds to me like the brake booster is doing what it's supposed to. As the vacuum comes up with the engine running, it's allowing the power assist to easily compress the air in the system and feel like a soft pedal.

I'd lean towards there still being a significant amount of air in the system. I too highly recommend speed bleeders, even if you are doing a two-person bleed.

In the process of bleeding the brakes did you happen to let the master cylinder go dry on accident? If so, you probably have a fair amount of bleeding left to do.

Also, make sure if you haven't already that you don't have a wheel cylinder in the rear that has come apart or a leak in the lines somewhere. Does your fluid level remain constant when you pump the pedal, or does it drop?

-Rod

[edsel]

shorod, i am not loosing any brake fluid, but it has to be something with the wheel cylinders. i am going to check it on thursday when i return home from work. thanks again. if it's not the wheel cylinders i am back to square one. bleeding the heck out of it again or returning the defective autozone master cylinder. thanks again edsel....

[tripletdaddy]

Are you sure that when the engine is off that when you stand on the brakes that the pedal doesn't creep down any? But with the engine on it goes to the floor. Weird. I'd think with trapped air it would go down irregardless if the engine is on or not, just easier with it on. Are you certain you are not using fluid? Compare results with engine on versus engine off. Have you looked at the wheel cylinders for leakage yet. I'd bet if you have a leaky cylinder, you will see your fluid go down with the engine on and I guess not with it off. What I really expect is when you push on the brakes with the engine off, the fluid level in the reservoir doesn't move much as you have attested, but with the engine on you can push further on the pedal, compressing air trapped in the lines. Evidence of this, if you can catch it happening, is the fluid level will drop a bunch with the pedal down (or even pump it a bunch) and then pedal off, the fluid will come back up. With a leak, the level won't return to its original level. Did you possibly allow air into the system with the reservoir getting too low? Are your brakes actually working at the wheels with engine off and engine on?

[cj091184]

Just a thought, when bleeding the brakes make sure the car is level, I usually bleed once with the wheels of and the again when its all together and sitting level. also when bench bleding the master try holding it at an angle, somtimes when a master sits at an angle air will rise to the higher end and become traped, When I bleed brakes I use a rubber hose and a container, attach the rubber hose to the bleeder and put the other end in the conainer sumerged in a small amount of brake fluid, make sure the master is toped off, open the bleeder and the pump the brakes 6-8 times, close the bleeder top the fluid and repeat if you see air bubbles in the rubber hose. "The hose is to prevent the bleeder from sucking air back into the lines." I use this method wether or not I have an assistant". Good Luck

[edsel]

FINALLY...after bleeding the brakes about ten times, round and round, i finaly got brake pedal!!!! anyway got it done. thanks for the help and being there. edsel......