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Brake troubles!!!!!

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Old Jul 2, 2006 | 08:18 AM
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Default Brake troubles!!!!!

Guys
on my 74, have replaced proportioning valve and on the second master cylinder - at all four wheels I get fluid flowing soon as I open the bleeder valves -
pedal still goes to the floor !! What could be the next thing to try??
Thanks
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Old Jul 2, 2006 | 08:52 AM
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Originally Posted by BIGJIM13
at all four wheels I get fluid flowing soon as I open the bleeder valves -
Excuse me for asking a stoopit question but when you say "fluid flowing" this is with pressure on the pedal...correct?

Other than that I would have to guess trying a power bleeder...hopefully someone with more brake experience than myself will pop in soon with better advice
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Old Jul 2, 2006 | 09:16 AM
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Thanks - just gravity bleed - I open the bleeders in the proper sequence and let it flow then close the bleeder.....if the boost is defective, what condition would it give?
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Old Jul 2, 2006 | 09:35 AM
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I know there are some that go with this gravity bleed, my feelings...that might take a long time to get it to work...
Might I suggest you use the standard practice...find some unsuspecting volunteer to pump the brakes up, open the bleeder, suspect foot to floor, close bleeder, repeat 3 or 4 times, go around the car twice....there is also a specific order of bleeders to follow...9.5 times outta 10, this will give ya good brakes..
Just my 2 cents...
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Old Jul 2, 2006 | 09:51 AM
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Did you do a bench bleed of the MC? I know that gravity bleeding is favored by some but I pressure the old tried-and-true step on the peddle and open the bleeder method.

Gary
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Old Jul 2, 2006 | 12:25 PM
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Thanks - master was bench bleed - did the (guy in the car pedal method) same results...thats why I tried the gravity method...same results... does not make sence as to why the pedal still goes to the floor!
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Old Jul 2, 2006 | 12:47 PM
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When you bleed the brakes with a helper, do you get fluid coming out under pressure (more than gravity bleeding)? Are you sure you have the right length pushrod for your MC and booster? All this points to another bad MC if you aren't getting any pressure anywhere.
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Old Jul 2, 2006 | 04:14 PM
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Originally Posted by BIGJIM13
Thanks - just gravity bleed - I open the bleeders in the proper sequence and let it flow then close the bleeder.....
Without pressure in the sysyem wouldnt this method introduce air into the system?
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Old Jul 2, 2006 | 07:24 PM
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Thanks
when pressure bleeding with a helper - I get a good expected squirt...
thats why this does not make any sence..pushrod has been checked
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Old Jul 2, 2006 | 09:25 PM
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Be sure the car is not running. have someone pump the brakes untill you have a pedal. go to the fartherst brake rt rear. by the way it takes two to do this. connect hose to the bleeder insert in clear jar keep pressure on brake pedal. let flow untill pedal reaches floor looking for bubbles. when pedal reaches floor leave there untill you close bleeder. pump up the brakes again. repeat keeping an eye in bubbles coming out. when there are no more bubles go to the next fartherest (lr) do the same as above. when no more bubbles go to the rf and repeat when no more bubbles go to the lf and do the same. be sure to monitor fluid level at all times do not let it get too low.
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Old Jul 2, 2006 | 09:53 PM
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Originally Posted by 694speed350
Be sure the car is not running. have someone pump the brakes untill you have a pedal. go to the fartherst brake rt rear. by the way it takes two to do this. connect hose to the bleeder insert in clear jar keep pressure on brake pedal. let flow untill pedal reaches floor looking for bubbles. when pedal reaches floor leave there untill you close bleeder. pump up the brakes again. repeat keeping an eye in bubbles coming out. when there are no more bubles go to the next fartherest (lr) do the same as above. when no more bubbles go to the rf and repeat when no more bubbles go to the lf and do the same. be sure to monitor fluid level at all times do not let it get too low.
There has been some discussion on the forum recently regarding bleeding sequence. I just bled the brake system on the 72 today and the sequence (supposed to be factory recommended) is Left Rear Inner, Left Rear Outer, Right Rear Inner, Right Rear Outer, Left Front, Right Front. This sequence is contrary to standard procedures, but I followed it and it worked great.

BTW, I bought a vacuum bleeder and went through over a quart of fluid and still had huge amounts of air coming through the first bleeder. I switched to my trusty $2.99 tiny-reservoir-with-hose bleeder and got much better results. I think the air-powered bleeder was sucking air though either the seals or the rubber cap on the bleeder.

about monitoring the fluid level. My son forgot to check the level while I was bleeding the RR caliper and we had to start all over again because air had been sucked into the line. After that I had him top off the reservoir every time I emptied the bleeder.



Rick B.
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Old Jul 2, 2006 | 10:10 PM
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Default get a vac pump

i had that problem and went and bought a mighty vac hand bleeder. you can get at parts store. and it gives instructions on how to bleed.and you wont get air sucked back in. there cheap even cheaper if you live near a harbour freight tools.
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Old Jul 2, 2006 | 10:52 PM
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Originally Posted by BIGJIM13
Thanks
when pressure bleeding with a helper - I get a good expected squirt...
thats why this does not make any sence..pushrod has been checked
You said in a previous message that the peddle goes to the floor. How is the helper pumping up the brakes if it goes to the floor each time. Don't you pump up the brakes and hold pressure on the peddle while someone bleeds the wheel cylinder. Believe it or not, I use The Club to put pressure on the brake peddle by extending it up and locking it under the steering wheel while I go to the wheel cylinder and bleed it.
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Old Jul 2, 2006 | 10:55 PM
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Originally Posted by Bob Onit
Without pressure in the sysyem wouldnt this method introduce air into the system?
Only if you let the master cylinder run dry.
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Old Jul 2, 2006 | 11:01 PM
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Default Pressure bleeder

I used one of these: http://www.apexperformance.net/cartg...p?pid=46&cid=8

When I first tried to bleed the brakes the pedal would not pressure up at all. Thus I would get no fluid out of the bleeders. Then I used this device and in less than an hour -- and two bottles of brake fluid -- i had great brakes. This is a tool that everybody should use when bleeding their brakes.

wayne h.
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Old Jul 3, 2006 | 04:09 AM
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Just one more comment and we'll see how you make out....
You do realize there are 2 bleeders on each of the rear calipers, right?
Just had to ask...
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Old Jul 3, 2006 | 09:54 AM
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Jim, you also have to let wuite a bit of fluid out to make sure the bubbles in the middle and top of the line get all the way to the caliper and out of the system, if you didn't and just cracked the bleeder, got a couple squirts and closed it up, you still have a bubble in the middle of the line. Keep the res full and pump at least 2 cups thru the system before moving on to the next wheel.
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Old Jul 3, 2006 | 09:41 PM
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Guys
thanks for all the suggestions - I have pumped and pushed quarts and still do not get a hard pedal - goes down.. can the boost be bad?
when I bolt up the master there is a point where it contacts the push rod where I have a gap of about 1/8 inch before it butts to the boost ..so the rod is right!
Thanks
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Old Jul 4, 2006 | 08:54 AM
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Guys
thanks for all the suggestions - I have pumped and pushed quarts and still do not get a hard pedal - goes down.. can the boost be bad?
when I bolt up the master there is a point where it contacts the push rod where I have a gap of about 1/8 inch before it butts to the boost ..so the rod is right!
Thanks
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Old Jul 4, 2006 | 08:59 AM
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Generally if the booster is bad you have to push very hard to stop, but you can still get a firm pedal.
Are you getting any air when you bleed them? Visable bubbles?
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