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2000 Deville Base, 2019 Corvette GS
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Discussion Starter #1
So I blew a brake line, lost most of the fluid and had the line fixed. Everything is tight no leaks. We then proceeded to bleed the lines starting in the right rear etc..We bled each wheel three times and still have a mushy and low pedal. So we put the car on the scanner and had the computer bleed the lines automatically. Still the same. The only problem is the front calipers bleeder screws are rotted and we bled the fronts from the brake line hose, not the bleeder screw. Some one told me you really can't get all the air out that way because the brake line is lower than the bleeder screw. He also told me you do not need to bleed the lines from a scanner, you can do it manually like we did. Does all this make sense and is there anything I need to know that I am not doing now?
 

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2001 eldorado,2008 DTS,2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
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How are you bleeding the system? Pushing on the pedal? Using a hand held vacuum pump? Gravity?
What is this 'scanner you talk about?
 

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92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
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Also, the master cylinder needs bleeding since all of the fluid war pumped/drainef out through the leak.
 

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2000 Deville Base, 2019 Corvette GS
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Discussion Starter #4
Bled the old way first, pumped brakes, held pedal down, opened. Did each wheel three times. Then bled it with the scanner. Snap On scanner. You hook it up, follow the instructions and it does everything thru the cars computer. Are these brakes the JL9 or J55 (my car is a base Deville)
 

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2011 CTS4 Coupe, 2014 ELR, 2018 XT5 AWD
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I think you cannot get all the air out of the caliper by bleeding it at the hose.
 

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2000 Deville Base, 2019 Corvette GS
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Discussion Starter #7
I think you cannot get all the air out of the caliper by bleeding it at the hose.
Yup that's the consensus, hence why the bleeder screw is at the very top of the caliper. So I just bought new calipers just to get new working bleeder screws. We will put them in tommorow and hope that was the problem.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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How do you bleed the master cylinder
=======================
you have the standard JL9 brakes - J55 have the 8-lug rotors

if you ran the master dry -
you might have to remove it from the car and bench bleed it to get ALL of the air out -

I'm also somewhat concerned about using the pedal method of bleeding -
this will very often "kill" an old master cylinder by destroying the internal "O" rings
when they travel beyond the "usual" working area -

if the pedal pumps up - but slowly sinks as pressure is held -
you DO have an internal leak - replace the master -

I agree with CSIMME -
you simply can't get air out of the calipers by cracking the flex lines -
the air - and bleeder screw - are at the highest point of the caliper -
the brake line is much lower -
 

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Discussion Starter #9 (Edited)
=======================
you have the standard JL9 brakes - J55 have the 8-lug rotors

if you ran the master dry -
you might have to remove it from the car and bench bleed it to get ALL of the air out -

I'm also somewhat concerned about using the pedal method of bleeding -
this will very often "kill" an old master cylinder by destroying the internal "O" rings
when they travel beyond the "usual" working area -

if the pedal pumps up - but slowly sinks as pressure is held -
you DO have an internal leak - replace the master -


I agree with CSIMME -
you simply can't get air out of the calipers by cracking the flex lines -
the air - and bleeder screw - are at the highest point of the caliper -
the brake line is much lower -
Are you saying if this happens AFTER I replace the calipers? Because that is what it does now. I was hoping the air that is in the system now is what is causing my low and spungy pedal, not a bad master cylinder. This could be getting expensive for a stupid broken brake line.
 

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92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
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Bleeding MC - shade tree:

Lots of towels, small flat pan, extra dot 3.

Top off fluid.
Pan and towels under MC.
Pump pedal a couple times and hold at 50%-75%
Crack lowest level brake line connection to release pressure and air.
Tighten connection
Repeat until no more air (sputtering)
Repeat for higher brake line connection

(Keep fluid topped off)

Note, there are after market MC with a bleed fitting mounted on the upper side of the cylinder. Check if you have one of these.
 

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2000 Deville Base, 2019 Corvette GS
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Discussion Starter #11
Are you saying if this happens AFTER I replace the calipers? Because that is what it does now. I was hoping the air that is in the system now is what is causing my low and spungy pedal, not a bad master cylinder. This could be getting expensive for a stupid broken brake line.
Actually I just drove the car and when you pump up the brakes it does hold whatever pedal I do have, about 50%. So I am hoping the master cylinder is still good and the low and spongy pedal is indeed air in the lines. When the line broke I never let the master cylinder run dry, I kept refilling it and the pedal never went to the floor, low but never the floor. Will know tomorrow when I re bleed after replacing the front calipers and am able to bleed the lines correctly.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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a low pedal is USUALLY rear brakes - either drum or disc - that are out of adjustment -

a spongy pedal that can NOT be pumped up is USUALLY air in the system -

a pedal that sinks when you hold pressure on it is USUALLY a leak - either internal or external -
 

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2011 DTS Premium w/1SD | 1999 Deville Base (RIP @179K Miles)
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If the new calipers don't fix it, I'd try bench bleeding the master cylinder. If you're a DIY person, it's not too hard to replace and bleed the master cylinder.

Was the brake line that goes over the exhaust in the rear the one which broke?
 

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Discussion Starter #14
This all happened AFTER I ruptured a brake line. Everything was fine and in great working order before this and the components are in good shape. The line that broke was under the front splash shield a little to the passenger side running along the front frame rail under the radiator. It didn't actually break, it was rubbing on something and wore thru. Here is the picture of the damaged line we cut out and replaced with a compression fitting.


589390
 

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Ron:
When bleeding, keep the master topped off so you are not pumping air. Also, be sure to install the new calipers with the bleeders on top. You'll never get them bled with the bleeders on the bottom.

Don
 

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2010 DTS
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Here is the picture of the damaged line we cut out and replaced with a compression fitting.
Ron, compression fittings are NOT considered a safe repair for brake lines. That repair may fail catastrophically some day when you really need it.
 

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2011 CTS4 Coupe, 2014 ELR, 2018 XT5 AWD
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I agree with ranger.
Either replace the entire section (the best solution) or cut, add flare fittings and a new section of line. It is is short enough you may be able to flare both ends and connect with a brass fitting. A compression fitting is not a safe, approved repair.
 

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2000 Deville Base, 2019 Corvette GS
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Discussion Starter #18
I understand you guys concern but with what is at my disposal a compression fitting was my only choice. There is really nobody around me that is competent enough to do brake lines or don't want to bother. My mechanic who I use for everything does not flare brake lines nor really gets involved with brake lines period. But I am sure if I found the actual line that was damaged and found a replacement line he would install it. The guy that put the compression fitting in and found the bad line is not my regular guy, he did it in a emergency and basically did me a favor just getting the leak fixed.
 

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Discussion Starter #19
Just came back from a highway run of about 10 miles. Don't know what actually happened but I now have more pedal and firmer, not quite right but definitely better than what it was. Shame I have to go for the money of new calipers, installation and more bleeding for two bad bleeder screws when it seems to be I am now at about 75% pedal feel. But you can't skimp out on brakes and I need them obviously to be 100% working. So I am basically paying $200-$250 for two bleeder screws.
 

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Discussion Starter #20
Just had the new calipers put in and bleed the system first manually then bleed it again with the scanner, all is now good.
 
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