ok so i was doing my front rotor an pads install on my 85 gt (stock rotors an pads) so when i do any brake job i always remove the master cyl cap/cover to easily make the piston go back in. but after i did this an finished both sides i put my tools away, went to start the car, touch the foot on break an it went right to the floor. i forgot to put the master cyl cap/cover back on :-( i was in a rush so now i got no brake pedal an a ton of air bubbles in the master cyl. so i tryed bleeding brakes going in this order rr, rl, fr, fl but my pedal is still terrible an traveling to the floor i noticed there is a bleeder on the proportional valve on the back side of it if i open this will this take the air out of the master then bleed in the order as above ??????

Always start with the left rear on a fiero. It is the farthest one from the mc.

i think you have to bleed the M/C first

It's also possible you may have damaged the mastercylinder seals by allowing it to travel over the area of the bore that it normally does not, that may have residual build up on it, if bad enough it can tear the rubber seals when they move across it.

I'd probably just bleed the whole system on this one. The MC may need to come off the car and be bench bled in a bench vice, but you can try putting a bubble level on it with the MC cover on and jacking the car up until its level. Either way, its not a bad job. After that, gravity bleed the brakes in the order previously described. You can have the car good as new in a few hours, or if you really want you can do each caliper for about an hour each and make a day of it. The bonus there is that you know the system is bled really well.

It's too late now but if you had just put the lid back on after you realized you left it off and pumped the pedal, all would have been good. With the cover off, when you hit the pedal all that happened is the fluid went skyward and created bubbles when it came back down and hit the surface. The pedal will go to the floor anyway when pushing the piston back in while replacing pads as the piston has to travel a little to get back to position. Usally one or two pumps.

Kevin

Having the cover removed from the master cylinder and pumping the brakes WILL NOT introduce air into the braking system. The only thing that would have happend in a normal working system when pressing the pistons back in, is that the fluid level in the reservoir would have raised and possibly spilled out (depending on how worn your brakes were and if you added fluid at some time). The cover usually has a vent in it so air is in the reservoir all the time. The only way you will have air introduced (at the master) is to have the reservoir empty (which uncovers the pressure ports) and then pumping. And even then, it usually won't go anywhere. It's possible that you may have an issue with a master cylinder seal, or a seal in one of the calipers that may have introduced air into the system when pressing the pistons back into the bores... -Jason

[This message has been edited by Fierofreak00 (edited 12-12-2012).]

Well i saw a port on the back of the proportional valve that seems like a bleeder what if i bleed the master cly from there i did that on my 88 gta cause i wasnt getting brake fluid to the calipers i then bled each caliper an i had a solid hard brake pedal wondering if this will work for the fiero as well

quote Originally posted by pontiacfierokid1985: Well i saw a port on the back of the proportional valve that seems like a bleeder what if i bleed the master cly from there i did that on my 88 gta cause i wasnt getting brake fluid to the calipers i then bled each caliper an i had a solid hard brake pedal wondering if this will work for the fiero as well

prop valve IS NOT a bleeder hole. DO NOT mess with it.

If MC tank is low on fluid is only time air will get inside MC and likely need bench bleed.
If only front section got air inside MC bore then maybe can bleed at calipers.

Do Not MC cover off except to remove some fluid if tank too full and will go all over.
Leave cover loose if needed. MC will spray fluid normally when pedal is pushed.
See my cave http://home.comcast.net/~fierocave/brakes.htm and http://home.comcast.net/~fierocave/brakes4.htm

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

If you quickly stab the brake pedal with your foot do you get a firm and high pedal? If so your MC seals are not sealing. My guess at what maybe happened is first you pushed the pads back into the calipers. Then when you pushed on the brake pedal, the MC piston moved farther than it was normally doing, and pushed into the accumulated sediment and any corrosion in the farthest travel of the master cylinder. That sediment caused an already hardened master brake seal to start leaking. Stabbing the brake pedal causes the pressure in the system to rise quickly helping the umbrella seal of the MC to seal.

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+1 on the idea that unless your MC ran dry sometime there isn't much of a possibility that your hydraulic system has air in it.

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If stabbing the brake pedal doesn't give you a firm/high brake pedal, does pumping it? If pumping the brake firms it and brings it up high, then your problem is indeed air in the system.

Yea thats the thing i been bleeding for about 2 hours now an everytime i pump the pedal it does get hard an is right at the top after bleeding an when we think its good ill pump the pedal again to see an it still feels soft an travles mid way but the thing is no brake light comes on in the car

Not necessarily. The pressure is leaking past the first seal back to the tank. Not past the last seal that would not get damaged due to pushing the peddle to far down. There are usually three seals. Front brakes, rear and piston shaft end.

The old school way is to put a 2x4 under the peddle when bleeding so you don't push the peddle to the floor and mess up the seals. At least it's better nothing.

[This message has been edited by Dodgerunner (edited 12-12-2012).]

Yea i ordered a new master today it wont be here til friday so looks like im waiting acouple of days

Did you check for leaks in your brake lines? I've had a lot of old brake lines go when I first press the brake pedal after doing the brakes. I'd double check all the lines and hoses for leaks when someone presses on the brakes. Air has to be entering the system from somewhere, and it doesn't enter from the cap being off. Maybe you didn't put the washers on the bolt that connects the hose to the caliper, or if you replaced those, maybe one of the old ones is stuck to the caliper, causing a seal that isn't quite air tight.

Well i got another question i havent took any of the calipers off but what if the previous owner put the calipers on the wrong side like the left one is on the right an vise versa i know with new calipers this could happen an would cause the bleeder to be lower then the banjo bolt this would keep the air caught stuck in the caliper ???? Can someone post a pic of the stock caliper bolted on the knuckle showing the correct way so i can verify if its on the right way

You related to pontiackid86?

No unless i have a brother or sister that my mom an dad didnt tell me about lmao

Ok so today i got the master cyl in the car bench bled an all four calipers let alone to find out that i still have the to pump the pedal to bring it up to the top once i leave the pedal alone for a few seconds go to tap the brake travels right back to the same position mid travel then have to pump it again to keep it at the top i bled for like a half hour there is literally a pool of brake fluid in my driveway getting really frausterated with this damn thing

Just a dumb thought . . . do you have someone helping you open and close the bleed screws when you are bleeding the calipers?

Build pressure with brake pedal, open bleed screw, push brake pedal to floor to push out fluid, close bleed screw before leaving up brake pedal, build pressure, open bleed screw, push out fluid, repeat till no air bubbles show in fliud leaving caliper? Attach a line from bleed screw into a catch can with fluid already in it so you do not suck air back into the caliper if you do not get the bleed screw closed before leaving off the brake pedal?

Been doing it this way for 30+ years now and have never had a problem, have never had to bench bleed a master cylinder either.

Are you using speed bleeders? (not sure if that's what they are called)

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"There is no more formidable adversary than one who perceives he has nothing to lose." - Gen. George S. Patton
http://www.flowbenchtech.com

If it's the original mastercylinder chances are it was ruined when the pedal went to the floor. I've changed out a few and never had to go through the difficulty you are going through now to get a good pedal. The cup seals are probably damaged now and that's why you're still dealing with the same problem, about like a bad clutch mastercylinder. Fix it with a new one.

I found out that it has to do something with the parking brake if i pull the parking up which doesnt work anyway. Them if i touch the brake the pedal stays at the top everytime i pump it even if i wait a minute an then pump it again its right at the top

quote Originally posted by pontiacfierokid1985: I found out that it has to do something with the parking brake if i pull the parking up which doesnt work anyway. Them if i touch the brake the pedal stays at the top everytime i pump it even if i wait a minute an then pump it again its right at the top

By applying the e-brake you've eliminated some of your brake travel because the rear pads are now closer, or pressed against the rotors. You would feel the difference even if the mastercylinder was working properly.

messing w/ ebrake?
Likely ban piston(s) in rear
See my Cave, Rear Brakes

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)