SmuurF420

87 v6 2.8 Liter auto camaro
front disk
rear drum

heres the deal..
ive replaced with brand new parts the following:
front:
rotors
calipers
pads
hoses
all new clamps, springs, bolts etc.
rear:
wheel cylenders
shoes
ebrake levers
springs, nuts, bolts, etc.
outter drum housing
rear hard lines
basically ive replaced everything
now that everything is put together and no leaking anywhere, ive bled the brakes about 20 times each wheel... still no brake pressure when i turn the car on.. when its off the pedal will pump up n be really stiff. until i turn the car on.
is there maybe still air in the system? or any1 think there might be somthing else?
thankx for the help
joe

Chickenman35

You've still got air in the system.

If you let the master cylinder run dry when you were working on things you will have to take the M\C off and bench bleed it.

Simple thing...but make sure that you did not install the calipers on the wrong side. Bleeders must be up.

When bleeding. Start at the farthest wheel...right rear, then left rear, right front and finally left front. Note the the right rear will take the longest to find an air bubble. Do not pump the pedal rapidly to build pressure...this will aeriate the fluid and cause more bubbles. In fact you don't need to pump the pedal at all. That is the best way.

When releasing the pedal....release it slowly. This also helps to prevent the fluid from being aeriated.

Tap the calipers whith a ball peen hammer. This will dislodge any air bubbles stuck in corners or clinging to the surface wall.

Hope this helps.

No4NJunk

If what chicken said doens't work (which it should) then try gravity bleeding the brakes. You'll need to bleed the MC first before anything. Then make sure there is enough fluid and open all the bleeders until they just barely drip fluid. Let them bleed for a little while. Then tighten and proceed from there. To bleed the MC you'll need a kit or some rubber lines to run back into the top of the MC where the fluid is.

SmuurF420

thanks for the info guys, ill try anything. I was talking with some car guys about my problem also. they think its the booster valve. since the brake pedal gets stiff and hard when car isnt running, and soft as hell when its running, but it will let me pump the brakes they start to work slightly but not enuff.. any ideas or comments?

crnsuperduty

I keep hearing about bench bleeding the master cyl. Can anyone explain how a little better?

No4NJunk

to bench bleed:

1) Remove all the brake fluid from the reservoir, (large syringe will work).
2) Remove lines and unbolt master cylinder and res.
3) You'll need a bleeding kit that comes with plastic fittings for the MC and clear plastic lines that are about 15" in length.
4) Position the MC in a vise so that is won't move (at work I just get one of the guys to hold it because I'm lazy).
5) Connect fittings and lines and let the lines hang below the MC.
6) Fill the reservoir with brake fluid and wait until the brake fluid gravity bleeds its way out of the lines.
7) Once the fluid is dripping from the lines, put them into the top of the reservoir into the brake fluid (don't put them to far down, just enough that the lines are in the fluid). Make sure there is plenty of fluid in the reservoir.
8) Now with a screwdriver press the piston in very slowly in while tapping the MC with a hammer or screwdriver to knock any air loose.
9) Wait until the air bubbles come out of the line and rise to the top of the fluid.
10) Now slowly release.
11) Repeat this procedure until there are no bubbles left.
12) Now install the master cyl. Remove fittings and install the lines.
13) Proceed to bleed the brakes starting from the RR, then LR, RF and lastly LF.

crnsuperduty

Sounds like I could do that in the car, if I had 2 people. I just have to unhook the lines and do the same thing. Using the brake pedal instead of a screwdriver. Where do you get the plastic fitting though?

No4NJunk

Yeah it could be done in the car but like you said, 2 people would be required. You can buy kits that contain the barbed nipple fittings and clear plastic lines at auto parts stores.

Brett H. - 89GTA

Do the kits come with metric fittings?

If not, to bench bleed the master cylinder I was planning to buy some M/C hard lines off a junkyard car and bend 'em so that they return the fluid back to the M/C.

crnsuperduty

Man, I just threw my old lines away too!! I have all new lines on my car. They are British, not metric. 3/16" for the front. Not sure about the rear yet, not done.

SmuurF420

i still have my old lines, and a new one with a stripped fiting.. ill have to try the bench bleed thing, and since ill have the master out, ill replace the booster valve also since im almost positive thats my problem.

Trickster

You can do it on the car with two people. Have one person in the car and with the cover off the master cylinder reservoir, have him (or her) slowly press the brake pedal and hold it. While he holds the brake pedal,the other person can loosen the front line on the master cylinder until fluid comes out and then tighten it. Repeat this process about three times, refilling the reservoir as it gets low. Repeat this same process with the back line fitting on the master cylinder. Refill the master cylinder and replace the cover. It is advisable to place several absorbent shop towels or rags underneath the master cylinder to catch the brake fluid that comes out and then flush that area with brake or carb cleaner to remove the brake fluid from the paint. After you have bled the master cylinder this way, you can now bleed the brakes. NOTE! it is also a good idea to wear safety googles when bleeding the master cylinder in this manner.

SmuurF420

all this info is great help.. now that ive bled everything, many times, im still having the same problem: car off-brake pressure.. car on: no brake pressure.. solution- booster. now my problem is that ive never taken a master cylender/booster apart.. is it just a unbolt and ur done.. or is there anything i should know first?

RB83L69

It's not the booster.

You have air in your brake system. Pure and simple.

At some point during your work, the master cyl ran dry. It got air in it.

However, the fittings for the lines are not at the highest point of the cyl; therefore, you can't possibly get it out by bleeding it while it's installed on the car. The air will remain trapped. You can bleed them from now till doomsday, but there will still be air trapped in the system.

You need to either remove the master cyl and bench bleed it properly; or, if you're real careful not to get any brake fluid anywher on your paint, you can unbolt it from the booster, and tilt it forward so that the cylinder itself (not the reservoir obviously) is level, and have somebody hold it still, and gently push and release the plunger a bunch of times. You'll see lots of air bubbles come up out of the little hole in the bottom of the reservoir. Keep doing it until the air quits appearing; then tilt it a little one way, then the other, and do it some more, to make sure you get every last bit of air out of there.

Leave your booster alone, it's not the problem.

Chickenman35

No....I really don't think that will solve it. But go ahead and try, I could be wrong...but I don't think so.

What you are not understanding is the operation of a Power Booster. There is a big, absolutely HUGE, freakin spring inside the Booster that works AGAINST the pedal effort. When the engine is off it is EXTREMELY hard to compress this spring. That is what you are feeling as " Brake Force ". In reality all you are feeling is the the effort required to compress the spring in the booster.

When you start the engine, engine vacuum is applied to a very large diaphram that " Assists " in compressing this spring. Then the pedal gets easier to press. It should still be very firm though. If it is long and soft, that indicates a Hydraulics problem. Either air in the system ....or a faulty Master Cylinder.

A Power Booster is a very, very simple device. They rarely fail. When they do it is usually due to small hole or tear in the diaphram. Then the pedal gets harder to push...not softer.

I've never heard of a Power Booster failing that makes the pedal get softer. Only way that that could happen is if the large spring inside breaks....and that is extremely, extremely rare.

Replace the vacuum check valve first, it's cheap and easy...but I really don't think that is the problem.

IMHO, you still have a hydraulics issue as mentioned. I'd take a long hard look at the Master Cylinder. I think it is defective. Even new Master Cylinders out of the box can be defective...especially rebuilt or cheap generic brands. If you bought a new Master Cylinder...return it as defective and try another.

BTW, I never buy rebuilt Master Cylinders...only new. How much is your life worth?

If you do decide to replace the Booster...DO NOT ATTEMPT TO TAKE IT APART!!! It takes special tools and that spring can take your head off. By a complete rebuilt or new unit from the aftermarket. ( Rebuilt Booster units OK because of their simplicity). Or get one from the wreckers. I really don't think the Booster is your problem though.

EDIT: RB83L69 beat me to it. We were typing at the same time.

Pat Hall

iTrader: (31)

I had a problem once that was kinda rare. I had just changed my 69 over to disc brakes and no matter how much I bled the brakes, I couldn't get a good pedal. It turned out to be an air pocket in the calipers. What I did was remove each caliper from the bracket and had my girlfriend pump the brake pedal til the piston was pushed out quite a bit. I then broke the bleeder valve loose and used a c-clamp to seat the piston all the way back into the caliper while the bleeder valve was open. On one side there was a big gush of air right when the piston finished seating. Had a rock solid pedal after that. This was even after giving up and taking it to a shop that couldn't figure out the problem either. It could be your master cylinder as well, but I figured I'd suggest trying this too. Since your calipers are new, there's probably a good chance there might be some air trapped in them.

SmuurF420

maybe if i explain this problem from beginning to end i can get a better understanding.. this might be long..

when i got the car, brakes were bad, driver side hose was almost completly shot, the car pulled to right when i brake hard. after a few months the brakes got worse.. rear shoes so worn they didnt even touch the drum anymore.. no ebrake either =\ eventually the driver side hose made it so the left caliper was sticking when i stopped and then started goin.. it would let go after awhile. one day the brakes just went out.. no pressure pedal went all the way to floor, and if u pushed it really hard all the way to the floor it would stop the car, but not very good at all. now that ive replaced everything calipers, rotars, pads, hoses, shoes, rear lines, rear wheel cylinder... im back to where i was before i did any work.. pedal gets hard when car is off, and goes to the floor when its running, if i push it all the way itll stop.. but not good, unless i pull the ebrake (wich works great now) ive bled the system many times from the wheels.. the air bubbles in the calipers idea is a possible..ill try that.. the weird part is that i noticed if i stick my finger in the wheel to feel the front pads.. there loose.. shouldnt they be almost snug to the rotar by now?? thats one reason im thinkin booster.. the fluid was able to get to the end of all the lines with gravity and slight pressure, but for some reason the caliper pistons arent compressing the pads to the rotar?? why is that? and as far as re-build parts i dont like them, i usually buy new and get the middle grade parts.. no cheap stuff and its not a race car...
hope this long post helps...
thanks
joe

rustybluebird

You need to rebuild or replace your master cylinder, the seals/o-rings are shot.