bled brakes now no brakes?

[txdmc]

So i bled and flushed my brakes out today, no air in there just the little tiny micro bubbles. Fire her up for a test drive and pedal goes to the floor! All connections are tight and the brakes worked good before. What am I missing here? I will say that I hear a louder than normal hiss when I press the brakes. Now when the car is off the pedal firms up, when its on is just goes to the floor.

[PJ Grady Inc.]

So i bled and flushed my brakes out today, no air in there just the little tiny micro bubbles. Fire her up for a test drive and pedal goes to the floor! All connections are tight and the brakes worked good before. What am I missing here? I will say that I hear a louder than normal hiss when I press the brakes. Now when the car is off the pedal firms up, when its on is just goes to the floor.

How old is your brake master cylinder? If it's old and the fluid was really black you may have finished off the seals by pushing the pedal to the floor when bleeding. Once the cylinder wall below the seal picks up any corrosion or debris you run the risk of seal failure with the bleeding procedure itself. Another possibility is the booster but less likely as the pedal is usually hard but braking power is poor when it's bad. Does the hissing noise come from the booster?
Rob

[txdmc]

I would agree with that. Im sure that the master cylinder is the original one. Ill just have to order a new one and get it over with.

[madstudios]

So i bled and flushed my brakes out today, no air in there just the little tiny micro bubbles. Fire her up for a test drive and pedal goes to the floor! All connections are tight and the brakes worked good before. What am I missing here? I will say that I hear a louder than normal hiss when I press the brakes. Now when the car is off the pedal firms up, when its on is just goes to the floor.

I had the same problem this week, I've replaced the calipers repairs, flushed and bled, but when we put fluid in the system, the pedal went all the way and we discovered that the brake master cylinder was very corroded and never replaced. We put a new one, and brakes are awesome now.


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[David T]

Sometimes an air bubble gets stuck right at the bottom of the reservoir and is difficult to dislodge. If you were bleeding and got good flow that won't be the problem. Sometimes you have to bleed more than once to get all of the air out. NEVER use DOT 5, you will not get the air out of it and will never get a hard pedal. If the old fluid was dark and thick you probably have corrosion in the master cylinder and ripped the seals when you pushed the piston into the corroded area like Rob said. If your master cylinder is bad you should check out your clutch too. If the brake (and clutch) have not been flushed every 2 years, both systems should be rebuilt.

[Mike Griese]

So i bled and flushed my brakes out today, no air in there just the little tiny micro bubbles. Fire her up for a test drive and pedal goes to the floor! All connections are tight and the brakes worked good before. What am I missing here? I will say that I hear a louder than normal hiss when I press the brakes. Now when the car is off the pedal firms up, when its on is just goes to the floor.

How did you bleed the brakes? A pressure bleeder? Someone pumping the pedal? A vacuum pump at the bleed nipple? If you didn't close the bleed nipple quickly enough or if you had the nipple open too far, air can get drawn through the threads leaving a big bubble at the caliper. Also, it's helpful to bleed the caliper farthest from the master cylinder first, then work to the next longest, etc. I suppose it is possible you now have a problem with the power brake booster if the pedal firms up when no vacuum is present.

[Will F.]

I have a brand new master cylinder for sale if you are interested.

Will

[txdmc]

thanks for all the replies! I had to order some dmc Houston items so I picked up a master cylinder as well. I how ever did not know about PJ Grady I will be ordering some things from them soon too! During the removal I noticed 3 things...... 1 that is the original master cylinder and 2 there was a lot of crap coming from around where brake lines go out from the master cylinder and 3 the gasket from between the master cylinder and power booster was bad as well. Lucky for me I live in dallas so I can get parts from Houston quickly..... un lucky I get to pay sales tax. Anyways I will let you all know what happens

[Will F.]

thanks for all the replies! I had to order some dmc Houston items so I picked up a master cylinder as well. I how ever did not know about PJ Grady I will be ordering some things from them soon too! During the removal I noticed 3 things...... 1 that is the original master cylinder and 2 there was a lot of crap coming from around where brake lines go out from the master cylinder and 3 the gasket from between the master cylinder and power booster was bad as well. Lucky for me I live in dallas so I can get parts from Houston quickly..... un lucky I get to pay sales tax. Anyways I will let you all know what happens

Rob at PJgrady is currently working on a set of SS brake lines, Talking to him he mentioned they will have the correct hex nut so when you install them in the stock locations they will not twist around when tightening them. I have the DMC huston ones, Nice braided lines and aside from the packages being labled wrong my only complaint was the hex nut. To tighten the metal line was a real pain in the ass. I had to insert a flat blade screw driver to keep them from rotating to get proper torque on the brake lines. Unfortunately like you my hoses were blown out and leaking so I need replacements ASAP.

Will

[txdmc]

I said the hell with it!! New master cylinder, new stainless lines and new refurbished calipers. I'll let you all know how it works out


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[txdmc]

So I got everything installed, feels a little soft. Had the back jacked up higher than the front when I bled them. Bled them twice, 2nd time felt a little better. Also pulls to the left a little.


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[txdmc]

To add to that there are no leaks on the soft line connection. But the caliper connections gave me hell. I have to really crank down everything on the calipers


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[txdmc]

just wanted to give an update on this. so I removed the master cylinder again and re bench bled it using a kit that had the fittings and tubes, of course some air came out and it was bled till none was present. I then bled the brakes using the method used in the factory service manual, the cars brakes are much better than before.

some one that I know had mentioned adjusting the rod that comes from the servo that pushes the master cylinder, I don't think that is needed. I may purchase a new check valve for the servo. what are signs the servo is going bad?

so the lessons learned here were this: 1. buy a factory service manual and read it, 2. get a 7/16 open end line wrench..... go get one now, don't say oh this one I have will work, drive your butt to the store and get one before you touch anything.

now that I have these fancy new brakes all my suspension/steering issues are even more present. the car still loves to pull to the left when you brake hard, but when you let go of the wheel the car pulls to the left anyways (need a new rack and alignment). Also I think the left rotor or wheel bearing may be bad, the right turns free but the left gets a little hung up, not bad just a little. also my shocks are originals so I plan on doing springs/shocks as well, the car dips when you give it hard braking from a about 40 mph. I will say this the car stops great now.

the one thing I am learning about my delorean is although it has over 100,000 (about 100,600 miles) a lot of the stuff is either original or was replaced in the late 90's at delorean 1 or delorean motor center.

[David T]

If the car is pulling to the left you need to determine if it is because of a sticking piston in a caliper or something wrong with the tires/suspension. Pulling to the left means the left caliper may be sticking. If one is sticking you should rebuild all of them. Check tire pressures. The check valves don't go bad but a quick check is if you still have boost after turning the motor off. Don't touch the pushrod unless you have to move the brake pedal a LOT to get braking OR the brakes don't fully release. A small adjustment has a big effect so make your adjustments in small increments. A wheel bearing will feel rough and makes noise. At your mileage I would just replace both front wheel bearings. Even if your pulling issue is brakes I would also have the alignment checked anyway. if you feel a lot of looseness in the steering you "may" need a rack or it could just be bad tie rod ends. Again, at your mileage I would just go ahead and replace the shocks but the springs aren't necessary unless you want to change the ride height. Before getting an alignment you need to check all of the suspension bushings, you probably need to replace some of them at your mileage and that may correct the pulling.

[txdmc]

the calipers that I got were re plated and rebuilt by hervey (don't start ive read it all). when I purchased them I got them "loaded", I don't think its a stuck caliper I checked them by having a helper push the brakes and look at each one grab down on the rotor. now my left rotor was the one that was a bit sticky. it would turn freely for about 75% of the turn then the other 25% of the turn it would stick just a little but still move.

I am will to bet its my crap front suspension components that will be replaced next.

[David T]

Make sure the pads can move freely in the caliper. File the edges if necessary.

[txdmc]

so i checked that front left today, the side of the caliper facing the suspension is not releasing all the way the pressure is let off the brakes. I further checking it appears that i have a warped rotor. like i said earlier 75% of the rotor turns free like it should then that other 25% grabs the pad even when there is no pressure on the brakes. i just installed new rebuilt, replated calipers with new pads, pistons etc. im also sure there is some other suspension issues that amplify these problems.