 Brake bleeding, Nothing but air from rear brakes |
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| Medtner3 |
 Oct 4 2020, 07:49 AM
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#1
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Member  Group: Members Posts: 187 Joined: 7-July 20 From: Cedar Park Member No.: 24,467 Region Association: None  |
Just rebuilt my rear calipers with seals from PMB Performance. Using a vacuum brake bleeder I started with the right rear caliper lower bleeder screw ( I have two screws) and initially pulled about an inch of brake fluid with lots of bubbles and then zip. I get zero brake fluid now.
What could cause this? I have no signs of any leaks and the brakes were not bad before I rebuilt the calipers. I read somewhere that I might need to bleed the proportioning valve or even pump into the caliper some brake fluid through the top bleeder ? I ordered a Motive pressure bleeder which arrives in a few days Attached image(s)   
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Replies
| mb911 |
Oct 11 2020, 06:36 AM
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#2
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914 Guru Group: Members Posts: 7,614 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest 
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Kind of have the same issue.. The entire brake system is new and I still can't get a good pedal.. Hope I didn't damage the new MC.
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| iankarr |
Oct 11 2020, 07:08 AM
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#3
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The wrencher formerly known as Cuddy_K Group: Members Posts: 2,567 Joined: 22-May 15 From: Heber City, UT Member No.: 18,749 Region Association: Intermountain Region
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QUOTE(mb911 @ Oct 11 2020, 08:36 AM)  Kind of have the same issue.. The entire brake system is new and I still can't get a good pedal.. Hope I didn't damage the new MC. How would you have damaged the MC? It's unlikely, unless you pushed the pedal to the limit while bleeding. Easy to avoid by putting a wood block behind the pedal. When the system is new, it definitely takes a bit of work and several round-trip bleeds to get the pedal firm. I also found it helped when I took a syringe and shot brake fluid up through the lower bleed screws (and out the tops). Speed bleeders help a lot, as you can use them alone, or in conjunction with a pressure bleeder like the motive. Took me nearly 2 liters of fluid to get the pedal firm. Also, if you've got new pads and rotors, they need to be bedded in...and that will affect your braking power. See the procedure on the PMB site. Eric also has a great writeup on gravity bleeding... https://www.pmbperformance.com/914tech.html Be safe and enjoy! |
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| mb911 |
Oct 11 2020, 07:10 AM
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#4
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914 Guru Group: Members Posts: 7,614 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest
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QUOTE(iankarr @ Oct 11 2020, 05:08 AM) QUOTE(mb911 @ Oct 11 2020, 08:36 AM) Kind of have the same issue.. The entire brake system is new and I still can't get a good pedal.. Hope I didn't damage the new MC. How would you have damaged the MC? It's unlikely, unless you pushed the pedal to the limit while bleeding. Easy to avoid by putting a wood block behind the pedal. When the system is new, it definitely takes a bit of work and several round-trip bleeds to get the pedal firm. I also found it helped when I took a syringe and shot brake fluid up through the lower bleed screws (and out the tops). Speed bleeders help a lot, as you can use them alone, or in conjunction with a pressure bleeder like the motive. Took me nearly 2 liters of fluid to get the pedal firm. Also, if you've got new pads and rotors, they need to be bedded in...and that will affect your braking power. See the procedure on the PMB site. Eric also has a great writeup on gravity bleeding... https://www.pmbperformance.com/914tech.html Be safe and enjoy! I am concerned it pushed down too far. I have a very soft pedal. Will try to bleed again soon. |
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| Medtner3 |
Oct 11 2020, 08:31 PM
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#5
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Member Group: Members Posts: 187 Joined: 7-July 20 From: Cedar Park Member No.: 24,467 Region Association: None |
QUOTE(mb911 @ Oct 11 2020, 08:10 AM) QUOTE(iankarr @ Oct 11 2020, 05:08 AM) QUOTE(mb911 @ Oct 11 2020, 08:36 AM) Kind of have the same issue.. The entire brake system is new and I still can't get a good pedal.. Hope I didn't damage the new MC. How would you have damaged the MC? It's unlikely, unless you pushed the pedal to the limit while bleeding. Easy to avoid by putting a wood block behind the pedal. When the system is new, it definitely takes a bit of work and several round-trip bleeds to get the pedal firm. I also found it helped when I took a syringe and shot brake fluid up through the lower bleed screws (and out the tops). Speed bleeders help a lot, as you can use them alone, or in conjunction with a pressure bleeder like the motive. Took me nearly 2 liters of fluid to get the pedal firm. Also, if you've got new pads and rotors, they need to be bedded in...and that will affect your braking power. See the procedure on the PMB site. Eric also has a great writeup on gravity bleeding... https://www.pmbperformance.com/914tech.html Be safe and enjoy! I am concerned it pushed down too far. I have a very soft pedal. Will try to bleed again soon. The Master is fine it was just air in system still |
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| Medtner3 |
Oct 11 2020, 08:33 PM
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#6
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Member Group: Members Posts: 187 Joined: 7-July 20 From: Cedar Park Member No.: 24,467 Region Association: None |
QUOTE(Medtner3 @ Oct 11 2020, 09:31 PM) QUOTE(mb911 @ Oct 11 2020, 08:10 AM) QUOTE(iankarr @ Oct 11 2020, 05:08 AM) QUOTE(mb911 @ Oct 11 2020, 08:36 AM) Kind of have the same issue.. The entire brake system is new and I still can't get a good pedal.. Hope I didn't damage the new MC. How would you have damaged the MC? It's unlikely, unless you pushed the pedal to the limit while bleeding. Easy to avoid by putting a wood block behind the pedal. When the system is new, it definitely takes a bit of work and several round-trip bleeds to get the pedal firm. I also found it helped when I took a syringe and shot brake fluid up through the lower bleed screws (and out the tops). Speed bleeders help a lot, as you can use them alone, or in conjunction with a pressure bleeder like the motive. Took me nearly 2 liters of fluid to get the pedal firm. Also, if you've got new pads and rotors, they need to be bedded in...and that will affect your braking power. See the procedure on the PMB site. Eric also has a great writeup on gravity bleeding... https://www.pmbperformance.com/914tech.html Be safe and enjoy! I am concerned it pushed down too far. I have a very soft pedal. Will try to bleed again soon. The Master is fine it was just air in system still but I have yet to try gravity bleeding. I intend to bed the pads in as soon as I am comfortable with the pedal firm enough |
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Posts in this topic
Medtner3 Brake bleeding Oct 4 2020, 07:49 AM
mlindner Chances are the brake fluid drained out of the mas... Oct 4 2020, 08:06 AM
Medtner3
Chances are the brake fluid drained out of the ma... Oct 4 2020, 08:25 AM mlindner Yes I would try the fronts first...I know that is ... Oct 4 2020, 08:36 AM Medtner3
Yes I would try the fronts first...I know that is... Oct 4 2020, 08:42 AM davep On a caliper with two bleed nipples, the top is th... Oct 4 2020, 08:55 AM Medtner3
On a caliper with two bleed nipples, the top is t... Oct 4 2020, 11:51 AM iankarr
On a caliper with two bleed nipples, the top is ... Oct 4 2020, 12:08 PM Medtner3
[quote name='Medtner3' post='2856582' date='Oct 4... Oct 4 2020, 01:42 PM Medtner3
[quote name='Medtner3' post='2856582' date='Oct 4... Oct 6 2020, 04:28 PM Olympic 914
It only pressurizes to 5-6 psi I wonder if tha... Oct 6 2020, 06:42 PM Medtner3
It only pressurizes to 5-6 psi I wonder if th... Oct 6 2020, 06:47 PM iankarr
[quote name='Olympic 914' post='2857140' date='Oc... Oct 6 2020, 07:59 PM Tdskip The other thing that I would add is that for whate... Oct 4 2020, 10:55 AM iankarr I like to use pressure (motive @ 5-10 psi) followe... Oct 4 2020, 11:12 AM rhodyguy Get some speed bleeders. One for each caliper. Ins... Oct 4 2020, 12:05 PM Gint Get some speed bleeders. One for each caliper. Ins... Oct 6 2020, 04:45 PM Amphicar770 I had no luck vacuum bleeding the 914, couldn... Oct 6 2020, 05:19 PM Medtner3
I had no luck vacuum bleeding the 914, couldn... Oct 6 2020, 06:49 PM rjames I could never get the brakes bled properly until I... Oct 7 2020, 11:07 AM Medtner3
I could never get the brakes bled properly until ... Oct 9 2020, 05:17 PM draganc Assuming you are not in a rush to drive the car I ... Oct 8 2020, 05:38 PM Medtner3 Damaged master cylinder or impatient? I put on spe... Oct 8 2020, 07:13 PM davep Have you correctly set the venting clearance on th... Oct 8 2020, 08:09 PM Medtner3
Have you correctly set the venting clearance on t... Oct 9 2020, 07:27 AM Gint Have you correctly set the venting clearance on th... Oct 10 2020, 09:55 AM Medtner3
[quote name='Medtner3' post='2857647' date='Oct 9... Oct 11 2020, 08:30 PM Medtner3 UPDATE: Pedal bled four times have a pedal now it... Oct 9 2020, 05:19 PM Frankvw I understans it is very frustrating yes. Keep up t... Oct 10 2020, 06:44 AM davep http://www.914world.com/bbs2/index.php?showtopic=3... Oct 10 2020, 09:27 PM |
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