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No brake pressure at all?!?!
#11
cudak888;128869 Wrote:How long did you bleed each line? I spent almost 30 minutes bleeding each of mine (traditionally - not vacuum or pressure bled) before I was convinced that there was no more air in each.

Believe me: There were times I was convinced that there was no more air in one of the lines, and decided to pump it three or four times just to make sure. As if Murphy were watching, I'd get air in the system on the last test stroke. This went on for ages.

Good to have two helpers too - one to pump, and the other to fill the MC.

-Kurt
+1 sometimes it can be a pain to get all the air out
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#12
you can try a vaccum pump brake bleeder.


basically what i see happening could be 2 things.

1) defect in a part of the brake system
2) you have lots of air still in the system

if the situation is #2 what is happening is you have micro bubbles of air in the fluid. you bleed it and have a solid pedal, leave for 10 hours
next day you come back and the pedal goes to the floor, because all the micro bubbles have condensed back into large bubbles in the brake lines.
if that is the case then the question is how are you bleeding the system.

you should have a fair amount of hose coming off the bleeder going into a cup of brake fluid. so once air i bleed from the system it cannot go back in.
then you just crack the bleeder a tiny bit, because if you open it half a turn to start the fluid going, air will leak back through the threads on the bleeder. you just want it open enough to release the fluid and get air out not have it freeflow out the bleeder.
next you want to make sure you have the brake bleeding in the correct order. longest line first, shortest line last.
Passenger rear, driver rear, passenger front, driver front is the order from longest to shortest.

the amount of fluid you use, don't be shy when i flush the system out or re-bleed i may go through a small bottle just to make sure i get all the junk out of the system. basically install the hose on the bleeder rear passenger, but the hose in a cup of brake fluid, open the bleeder a crack, and pump the fluid in the master down to near the bottom, then refill. and pump again. if you use a clear hose on the bleeder into the cup you will see tons of air bubbles.
once you have pumped the master down 2 or 3 times, close off that bleeder and move to the drivers side and repeat, getting all the air out, and you may pump down the master 2-3 times. yup its going to waste fluid, who cares just get the air out.
then move to the front, passenger and front driver remember to just crack the bleeder to get the brake pedal to pump the fluid do not open it more then 1/8 a turn. that will keep air from getting back into the system from the threads of the bleeder.some people pack grease around the base of the bleeder to keep air out then clean it off later.

now if you did that for an hour or 2 then the next morning came back and the pedal went to the floor again, i would start to suspect the master then prop valve and i would want to inspect all the brake lines under the car at the joints for wet spots or a bad crimp on the rubber lines for the brakes somehow letting air back into the system. because if i keeps doing that there is a leak somewhere pulling air back in.

there could be a problem with the master or the prop valve. the master could be letting air in through the piston going to the booster. problem is you need to pull the master out to look back there and see if it is wet. there is a weep hole on the bottom of the flange that connects the booster to the master. do you find brake fluid has weeped down the front face of the booster. might indicate a piston leak on the master, or you could have a leak from the master cover.

a bad prop valve is hard to determine, you would want to have a spare to swap in then if the problem stops you know the prop valve is bad. those can develop an internal leak between the drum and disc sections sometimes you see it leaking from the plastic sensor on the prop valve that tells the system if it is leaking on either the drum or disc side of the system.

I assume your brake warning light is working inside the dash and isn't lighting up all the time.
usually it lights up when you start the car then turns off when the engine is running.

i know one guy had a problem and his brake warning light on the dash was burned out and he didn't know but his pedal didn't feel right.

for right now i say go back to pumping air out of the brake lines and lets see what happens.
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#13
I appreciate all the great advice! I did a quick bleed again and it seemed the brake had a tad more pressure than before while running (crosses fingers). So I will take the advice and I will sit down and bleed the whole system over and over on each individual line and hopefully that works out. I need to take out my transmission today or tomorrow so I can replace the front pump o-ring/seal and the pan gasket/filter. Thank you all!
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#14
Good job, armyfox. Keep us posted.

Doc

[Image: 6y14ea.jpg]

Project started 8-7-10
Completed: All new suspension, rebuilt 351C H Code bored .030 over with mild cam and intake, new 3.50 TracLok, custom exhaust system
Current "mini-project": interior upgrade Undecided
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#15
Because of the change in pressure after the booster is activated (engine running) im inclined to say that could be the problem. Although it is a new part (rebuilt?) there could be a defect.
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#16
You may want to try a 24 hour gravity bleed. Just barely break the bleeder until you see fluid seep out and let it sit overnight and for a day. Just keep a close eye on the level in the MC before you turn in for the night and check it first thing in the AM.

[Image: 2rr7aiv.png]

Just cruising along minding our own business when BAM!!! The LAWS show up.
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#17
I went thru this with my mustang. I changed the front calipers from Mustangs unlimited due to the car had been sitting for years . Bleed, bleed and bled till the cows came home. So I called Mustangs unlimited and a senior sales rep (I Believe Kevin) told me to take the calipers off the rotor put a 2x4 between the piston. The most important part is to make sure the bleeder is at the 12 o'clock position and bleed it that way. As the caliper sat on my rotor the bleeder was the 3 o'clock position. ( I think) By bleeding it at 12 o'clock it took out all the air that was trapped. That solved my problem. Hope it does for you.
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