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Constant air when bleeding


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Splitbux
Novice

Jan 17, 2014, 9:07 AM

Post #1 of 17 (4666 views)
Constant air when bleeding Sign In

02 town and country 3.3 abs no t/c

Replaced all calipers Brake hoses and Brake line all calipers bleed fine except front left there is constant microscopic air bubbles that are mixed with fluid they are so small that they stay in fluid and don't rise to top. Brakes lose pressure after couple days after bleeding. Would a bad after cylinder cause just one caliper to do this cause it's just happening on front left


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 17, 2014, 9:39 AM

Post #2 of 17 (4655 views)
Re: Constant air when bleeding Sign In

? Head scratcher. OK - I would bet and hate gambling that that wheel's caliper or flex hose has a minute leak and must be pretty minute. It might not show a physical leak easily to find or hidden behind dust boot in caliper. Have to believe if air can get in then fluid under pressure of actual use can come out.

In bleeding there would be a very slight vacuum when closing a bleeder and going for another round and suspect even a small air bubble gets the tiny bubbles noticed somewhere in either of those two new items. You are losing pedal after a few days so it's there somewhere.

Troubles are that brake fluid is water soluble so if wet out driving it could rinse away evidence. Could the master cylinder do this? If it has four lines from it dedicated along the way to just that wheel it's possible or anything dedicated to just that wheel. You also mentioned brake "line"?? Does that mean you made up a section that was damaged or rusted?

If you did and used compression fittings that's both not legal and doesn't work well either so that would be the problem. Even proper flaring and unions can be iffy. You need a real good look at the new flare made and how the nut contacts that flare. It's pretty hard to find one exact length of pre made line with the flare nuts that you can bend exactly right for an entire section of line but possible.

You simply must look at everything carrying fluid to just that wheel's caliper including the caliper,

T



Splitbux
Novice

Jan 17, 2014, 11:36 AM

Post #3 of 17 (4644 views)
Re: Constant air when bleeding Sign In

Parts were changed in steps to see what was problem. Only caliper replaced with original Brake lines and flex hose were having exact bleeding problem changed Brake line and hose still having exact same problem. Don't think it's any of the parts that were changed since before and after still having same issues. Brake line was done properly with double flaring tool. The master cylinder has two lines going to abs then four coming out of abs only front left is having aeration type of fluid come out. I don't know if master cylinder would cause this. Maybe I got a faulty caliper


(This post was edited by Splitbux on Jan 17, 2014, 11:38 AM)


Hammer Time
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Jan 17, 2014, 12:18 PM

Post #4 of 17 (4636 views)
Re: Constant air when bleeding Sign In

Are you vacuum bleeding this thing?



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Splitbux
Novice

Jan 17, 2014, 12:39 PM

Post #5 of 17 (4629 views)
Re: Constant air when bleeding Sign In

no 2 man bleeding into a water bottle with hose.


Hammer Time
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Jan 17, 2014, 12:44 PM

Post #6 of 17 (4627 views)
Re: Constant air when bleeding Sign In

That's not a good idea to have water around brake fluid. The fluid is hydroscopic and will absorb the water.

I would get it pressure bled.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
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Jan 17, 2014, 12:45 PM

Post #7 of 17 (4626 views)
Re: Constant air when bleeding Sign In

OP: Is the problem on the side you put new metal line in? It is so easy to split the made up double flare if you used a part of good original line where you could work. Vacuum bleeding that HT just asked would be nice to know but something funky if it last with a good pedal for a few days and now a bit confused if just ONE or both calipers had unusual bleeding problems but only ONE showed air so what's the scoop or I'm missing something.

Another point is now that we know just two lines from master I can't believe a single line could pick on one side from there. Masters is pumping brakes to floor can travel into a crusty zone inside and tear up seals but still wouldn't pick on one side IMO and experience.

Is it consuming brake fluid for those three days?

What was the original reason for doing brake work other than plain wear out and parts replacement. Was something strange before any brake work?

Bleeding thru ABS would really like the vacuum bleed not just pump, bleed, hold, repeat game you can do without ABS and it's lines and flaming magic that could very likely trap air but doesn't make sense to me that it seem OK for a few days at all and not a problem right away?

T



Splitbux
Novice

Jan 17, 2014, 1:19 PM

Post #8 of 17 (4620 views)
Re: Constant air when bleeding Sign In

yes the problem is where the new metal line is but was doing the same thing with old metal line and old brake hose. both replaced and exact same problem is still there. purchased van used and it must have sat for a while because a day after purchase the front left caliper locked up on it and almsot caught fire so we replaced fronts then rear one locked up the next day so replaced the rear calipers. when bleeding with just calipers replaced original hoses and metal lines the front left was releasing constant air bubbles millions of very tiny ones that you can barely see. assumed it was brake hose because these vans are known for that so i replaced the brake hose while attempting to remove it the fitting was rusted on so i had to replace the brake line aswell. still same problem persists after doing all that. before changing anything but caliper it was having the same bleeding problem as i do now with all new parts. im thinking maybe the banjo bolt is bad or the washers around it might be bad.


(This post was edited by Splitbux on Jan 17, 2014, 1:21 PM)


Tom Greenleaf
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Jan 17, 2014, 5:12 PM

Post #9 of 17 (4601 views)
Re: Constant air when bleeding Sign In

Quote ">>im thinking maybe the banjo bolt is bad or the washers around it might be bad.<<"

Gotta help me help you. Does this use the copper washers on the flex hose block to caliper? Probably and they should be NEW not re-used. Been out of this game for a while sport so bear with me as we have to find out why this is doing this - not good as you must know.

Calipers are about always rebuilt not really brand new. There is room for flaws in anything but rebuilt stuff a higher chance. That bolt never came with any I ever bought and some you need to clean out small hole at bottom and then down from where it flows when you bleed for it to be clear with good flow for bleeding. Usually just drill bits in your hand will do.

Again, help us help you as none of us are there looking right at things.

* By any chance are calipers on the wrong sides? Bleeder should be highest point as it sets in place. Some can be put on wrong side and you'll about never get all the air out.

* ARE YOU CONSUMING BRAKE FLUID? Need to know that with a plain yes or no. You said it feels OK for a few days then goes soft pedal on you I take it and notice when bleeding some minute bubbles on that side. Not right of course. Not often but sometimes when you suspect it to hide small bubbles like a carbonated soda if you tap on the caliper they'll rise to the top.

* Vacuum bleeding would eliminate that with the right equipment.

** One thing I don't know and doubt is if this dual (all are) pressure system is part of master cylinder doing just fronts other rear OR if this is criss-crossed meaning FL+RR get fluid pressure from master and FR+LR for other section of master. That still doesn't account for the bubbles at all or loss of fluid quite yet. Said already that master cylinders don't normally go to the floor pushing rubber seals deeper than they have been in use over sometimes many years and can tear up the seals such that if so you could get lousy pedal or other issues pretty much leaving you with a spongy pedal that wont quit it but might be intermittent. Still that shouldn't pick on one caliper!

* I still wonder about your metal line job too. Is that an entire new line flare nut to the end or did you make a flare with original line? That's what I would do if line looked great where I could cut and make the connection for a brass union. Mopar OE flare nuts used to be and who know which ones too deep and stuck to the lines especially right where the metal line seals to the flex hose as it's exposed there. Any could but the deep flare nuts if used there were trouble and worse if vehicle is in or from a rust belt area which I am but could be trouble with some age anywhere.

Notes: You suspect this sat for a while. Rotors should have shown evidence of being in one spot too long. At some point you can't even machine/turn that out as it comes right back so rotors get tossed for new. THAT ISN'T THE UP FRONT PROBLEM - but if nothing done to the rotors they probably will come back to haunt you.

LEAK FINDING WITH BRAKE FLUID: Sail already it's water soluble AND make to be both rubber friendly and hygroscopic meaning it will absorb moisture from the air even. Read container it will say keep cap closed tightly for just that reason. Bellows at master fill is to keep ambient air out. If moisture invaded fluid enough then it really can allow for rust/corrosion in calipers or anywhere it is much faster plus the boiling point drops to near plain water. Maybe if an area or connection is suspect enough rinse and blow it real dry and clean, hold brake pressure and see if you can even get a finger damp with brake fluid right there.

Gotta find this if it means sending it out for pro help stating what you have noticed,

T

Can't fool with finding this web sites or not it must be found and fixed as it's brakes of course.



Splitbux
Novice

Jan 18, 2014, 11:26 AM

Post #10 of 17 (4585 views)
Re: Constant air when bleeding Sign In

I'm convinced it's a faulty remanufactuered caliper I'll buy another one.


Hammer Time
Ultimate Carjunky / Moderator
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Jan 18, 2014, 11:47 AM

Post #11 of 17 (4582 views)
Re: Constant air when bleeding Sign In

What do you think they did?......... put a hidden compartment of air in it? Where is the air coming from?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 18, 2014, 12:01 PM

Post #12 of 17 (4577 views)
Re: Constant air when bleeding Sign In

Quote question from an earlier post by me ">>* ARE YOU CONSUMING BRAKE FLUID?<<"

I don't know how to suggest crap if questions aren't answered...........

T



Splitbux
Novice

Jan 19, 2014, 7:49 AM

Post #13 of 17 (4562 views)
Re: Constant air when bleeding Sign In

no fluid loss.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 19, 2014, 8:09 AM

Post #14 of 17 (4558 views)
Re: Constant air when bleeding Sign In

OK, that mostly rules out (said mostly) air getting in thru a leak.

* Does a wheel feel warmer than the other side or even hot after bleeding when it feels OK for a few days?

* Does the rebuilt caliper have a custom bleeder sometimes used when the core it was made from broke one off hopelessly? Not certain all places would sell those.

* Could be elusive but already asked if calipers were on the wrong sides? Some will fit and bleeder isn't in proper location.

* Is flex line twisted up or setting in proper position as the original?

* If all else seems fine I'd plain pay to have this vacuum bled out as per any specific procedure for the car. ABS might be either screwed up or holding some air.

Crazy I'm running out of ideas!

Tom



Hammer Time
Ultimate Carjunky / Moderator
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Jan 19, 2014, 8:35 AM

Post #15 of 17 (4553 views)
Re: Constant air when bleeding Sign In

When I asked about vacuum bleeding, it wasn't because it was the preferred method. It was because bleeding that way will suck air through the thread of the bleeder and give you the illusion that you are pulling air out of the system when you are not. Vacuum bleeding is not recommended in many situations. Pressure bleeding is what I recommend.

If air is actually getting into the system, it has to be coming in somewhere and that doesn't sound real likely with only one wheel, although the master could do that at the LF wheel due to being so close but that doesn't sound likely.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Splitbux
Novice

Jan 21, 2014, 9:39 PM

Post #16 of 17 (4534 views)
Re: Constant air when bleeding Sign In

Thanks for all the responses guys. I initially thought of bad master cylinder because one symptom was while at Red light braked the pedal will drop about an inch sometimes which I heard can be sign of bad master cylinder but when bleeding it's just that front left caliper so I wasn't sure if master would cause air in just the front left. I'm going to buy a caliper and return it if it doesn't solve the problem. If not I'll probably take it to a shop :(


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 22, 2014, 4:08 AM

Post #17 of 17 (4529 views)
Re: Constant air when bleeding Sign In

I know we are beating this up but it is brakes and worth paying attention to. Master cylinder could be an issue. Already said I seriously doubt it could pick on ONE wheel by itself. They can be intermittent in holding a firm pedal or that more common slow drift fading towards floor at the pedal.


So it's possible to be bad but unlikely to be causing the issue with the ONE wheel thing IMO,


T







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