Brake bleeding.. Tried everything
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Joined: Sep 2014
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From: Pittsburgh Pennsylvania
Brake bleeding.. Tried everything
I'm stumped. I bled my brakes 5 times now and they still feel like sh*t. Twice manually, and 3 times with a Motive pressure bleeder. I did them in the order the service manual says, I never ran anything dry, and I used brand new DOT 4. I tapped through all the lines and calipers with a hammer to get out any trapped bubbles, and still, nothing. It can't be a leak, since the brakes were fine before I started, I was only doing a routine flush. I've run a dozen 12oz bottles of Prestone through the system and at this point I'm just wasting fluid.
The only thing I can think of is the ABS might need bled, but it shouldn't (I think) since I was just doing a flush and not fixing/replacing anything. The ABS was never on during the flush, so the module should still have the old fluid in it. (which was just old, not contaminated with air). Help?
The only thing I can think of is the ABS might need bled, but it shouldn't (I think) since I was just doing a flush and not fixing/replacing anything. The ABS was never on during the flush, so the module should still have the old fluid in it. (which was just old, not contaminated with air). Help?
Le Mans Master
Joined: Jul 2008
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From: 200 AGL
St. Jude Donor '15
can you describe in more detail how they feel? I assume soft. have you tried pumping them several times? how much force is being applied to slow you down? If there's enough braking force, you could try going 100% brake pedal while driving to cycle the ABS valves open. may seem silly, just trying to rule out things.
Drifting
Joined: Sep 2009
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From: cinnaminson n.j.
St. Jude Donor '14
Did you use something to suck out the reservoir before you started?
Are you sure no one stepped on the pedal with the reservoir empty?
If the answer is no to these 2 questions and you didn't open the system, then the only way to get air in the system would be to have the bleeder open on the return stoke.
When flushing fluid, you should not get air out of the bleeders, period.
Two other things will cause a low pedal on a 4wheel disc car.
1. Stuck caliper slides
2. Bad master cylinder
Since the brakes were ok the above shouldn't be a problem.
Does the pedal have excessive travel with the engine off and the vacuum depleted from the booster?
If so there is a problem, if not and the pedal only feels low with the engine running, there may not be a problem. You can start almost any car with power brakes and push the pedal quite far. If you did this driving you would be in a full out panic stop.
Did you drive it after you flushed it? I have been fooled into thinking there a problem after brake when there really wasn't. You would be surprised at how little effort and movement gives you a lot of stopping power.
Are you sure no one stepped on the pedal with the reservoir empty?
If the answer is no to these 2 questions and you didn't open the system, then the only way to get air in the system would be to have the bleeder open on the return stoke.
When flushing fluid, you should not get air out of the bleeders, period.
Two other things will cause a low pedal on a 4wheel disc car.
1. Stuck caliper slides
2. Bad master cylinder
Since the brakes were ok the above shouldn't be a problem.
Does the pedal have excessive travel with the engine off and the vacuum depleted from the booster?
If so there is a problem, if not and the pedal only feels low with the engine running, there may not be a problem. You can start almost any car with power brakes and push the pedal quite far. If you did this driving you would be in a full out panic stop.
Did you drive it after you flushed it? I have been fooled into thinking there a problem after brake when there really wasn't. You would be surprised at how little effort and movement gives you a lot of stopping power.
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Joined: Sep 2014
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From: Pittsburgh Pennsylvania
Soft, yes. I tried pumping them up but that doesn't build any pressure. I haven't test driven it yet (cant until spring) so I don't know how much force it'd need to stop. In leiu of hard stop to open the ABS module, would putting it in gear while its on the lift work? I figure if its lifted up and I let the back wheels spin and gently tap the brakes, it'll lock the front wheels and kick in the ABS. Like doing a burnout in midair, to help you visualize it.
Thread Starter
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Joined: Sep 2014
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From: Pittsburgh Pennsylvania
Yes, I sucked the master about halfway dry, so it was never run empty. When the engines off and I pump a few times the pedal gets hard as the vaccum depletes, so that's a good sign. I haven't taken it for a test drive yet, but it feels way worse even when stationary than before I started.
As for how air got in the system, when I was manually flushing I got out of sync with the person pushing the pedal for a moment, and opened on the return stroke. At this point I can't imagine any air is left though.
As for how air got in the system, when I was manually flushing I got out of sync with the person pushing the pedal for a moment, and opened on the return stroke. At this point I can't imagine any air is left though.
Le Mans Master
Joined: Jul 2008
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From: 200 AGL
St. Jude Donor '15
can you scrounge an assistant? have them pump the pedal while you watch the bleeders to rule out a possible leak there if you have not already. I think your ABS trick could potentially work as long as you can safely support the car from rocking. The other option is to hook up a Tech1 or 2 and cycle the ABS that way. If there's a chance you can drive it, i would personally do that.
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Team Owner
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From: Overwhelmed as one would be, placed in my position.... DFW, TX
St. Jude Donor '05
If there's been air into the ABS module, I found the ONLY solution was to take it in and have them bleed the ABS module for me. Of course, I admit to having accidentally drained the reservoir when bleeding, so your problem might be different.
Moderator
Joined: Jun 2004
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If you're using the motive bleeder, all you should have had to do was hold the brake pedal to the floor (I used an adjustable paint pole), pressurize the motive bleeder and start at the right rear. I did it by myself and just opened the bleeder until the fluid ran clean. You've got some air in it somewhere
Drifting
Joined: May 2007
Posts: 1,547
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From: Huntersville, NC
here is a pretty good tutorial on brake bleeding. I think you have blown the seal in your M/c and you are getting fluid bypassing the seal in the bore. That would account for your pedal never getting firm. It is either that or a leak. It can't be the ABS, it is shut off to the system unless the solenoids are activated, and they don't get activated during bleeding. so if you bleed the system in a static mode, then you should get a firm pedal if that portion of the system is bled of air.
If it is your M/c and you replace it you will still have a soft system and you will be making a trip to someplace with a tech2 to bleed the ABS.
The only thing I disagree with in the tutorial is filling the power bleeder with fluid. The fluid attacks the tygon tubing, and eventually you will have a rupture an blast brake fluid onto surfaces where it isn't desired. Just fill the M/c reservoir and pressurize, and watch the level go down. If you have to augment with a second helper and pressing the brake during pressure bleeding then you probably have crud buildup in your M/c as described in the tutorial. Then that carp can end up in the ABS. HMMMM wonder why ABS's fail?
If it is your M/c and you replace it you will still have a soft system and you will be making a trip to someplace with a tech2 to bleed the ABS.
The only thing I disagree with in the tutorial is filling the power bleeder with fluid. The fluid attacks the tygon tubing, and eventually you will have a rupture an blast brake fluid onto surfaces where it isn't desired. Just fill the M/c reservoir and pressurize, and watch the level go down. If you have to augment with a second helper and pressing the brake during pressure bleeding then you probably have crud buildup in your M/c as described in the tutorial. Then that carp can end up in the ABS. HMMMM wonder why ABS's fail?
Le Mans Master
Joined: Mar 2011
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From: Columbia SC
I bleed all my cars brakes and clutches with a MIghtyVac.
You just hook it up to the bleeder and open the bleeder slightly and pump on the vacuum handle. When done at a location just close the bleeder. If the MightyVac reservoir gets full just stop, dump it, check the MC reservoir and start again.
You just hook it up to the bleeder and open the bleeder slightly and pump on the vacuum handle. When done at a location just close the bleeder. If the MightyVac reservoir gets full just stop, dump it, check the MC reservoir and start again.
Team Owner
Joined: Apr 2001
Posts: 36,453
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From: Overwhelmed as one would be, placed in my position.... DFW, TX
St. Jude Donor '05
here is a pretty good tutorial on brake bleeding. I think you have blown the seal in your M/c and you are getting fluid bypassing the seal in the bore. That would account for your pedal never getting firm. It is either that or a leak. It can't be the ABS, it is shut off to the system unless the solenoids are activated, and they don't get activated during bleeding. so if you bleed the system in a static mode, then you should get a firm pedal if that portion of the system is bled of air.
If it is your M/c and you replace it you will still have a soft system and you will be making a trip to someplace with a tech2 to bleed the ABS.
The only thing I disagree with in the tutorial is filling the power bleeder with fluid. The fluid attacks the tygon tubing, and eventually you will have a rupture an blast brake fluid onto surfaces where it isn't desired. Just fill the M/c reservoir and pressurize, and watch the level go down. If you have to augment with a second helper and pressing the brake during pressure bleeding then you probably have crud buildup in your M/c as described in the tutorial. Then that carp can end up in the ABS. HMMMM wonder why ABS's fail?
If it is your M/c and you replace it you will still have a soft system and you will be making a trip to someplace with a tech2 to bleed the ABS.
The only thing I disagree with in the tutorial is filling the power bleeder with fluid. The fluid attacks the tygon tubing, and eventually you will have a rupture an blast brake fluid onto surfaces where it isn't desired. Just fill the M/c reservoir and pressurize, and watch the level go down. If you have to augment with a second helper and pressing the brake during pressure bleeding then you probably have crud buildup in your M/c as described in the tutorial. Then that carp can end up in the ABS. HMMMM wonder why ABS's fail?