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Prevent air getting into abs module


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Krokeefe0504
New User

Sep 17, 2021, 12:40 AM

Post #1 of 11 (401 views)
Prevent air getting into abs module Sign In

I am looking to replace my rear calipers on my 2010 Chrysler Town & Country Touring 4.0. I would like to know what is the best way to avoid air getting into the abs module. Would using something to keep the brake pedal depressed a few inches and plugging the brake hose with a plug keep any air that gets into the lines from reaching the abs module?


Hammer Time
Ultimate Carjunky / Moderator
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Sep 17, 2021, 4:04 AM

Post #2 of 11 (396 views)
Re: Prevent air getting into abs module Sign In

Nothing will work unless you can stop the flow at the caliper. About the only way to do that is to pinch off the rubber flex hose at the wheel. Although this is done quite often, it is not really recommended as you could damage the hose internally.

A flush of fresh fluid is always a good idea anyway but as you are suspecting, you may need a professional scan tool to bleed out the ABS unit after doing that.



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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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Sep 17, 2021, 5:06 AM

Post #3 of 11 (384 views)
Re: Prevent air getting into abs module Sign In

Just on flex brake hose: Agree NOT to pinch it. The idea of that is STRONG on inside, what you see is to protect that. It for any reason it kinks, gets pulled (allowing caliper to fall for example) you risk instant failure right away or by surprise later.
Nuff said,


T



Hammer Time
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Sep 17, 2021, 5:32 AM

Post #4 of 11 (381 views)
Re: Prevent air getting into abs module Sign In

I'm not going to disagree with Tom about the potential damage to hoses but I will say I have successfully done it many times in the past. They do make tools with rounded edges specifically for this purpose.





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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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Sep 17, 2021, 6:10 AM

Post #5 of 11 (377 views)
Re: Prevent air getting into abs module Sign In

! Those look like the least risk. Gee HT now I have to buy more tools!
More hose failures that came my way were the crimp metal at ends either stressed or yanked on at one time. If seen rusty/flakey toss those just anyway.

It's just not funny to instantly lose all braking, usually when applied hard for some real serious reason.

That lurking would bug me, Tom


Krokeefe0504
New User

Sep 17, 2021, 11:32 PM

Post #6 of 11 (352 views)
Re: Prevent air getting into abs module Sign In

Thanks for the advice. In trying to avoid pinching the brake hose (even with the tool that seems to be safer than others at damaging the hose), I was thinking of this idea and would appreciate your thoughts.

Unbolt caliper and support it so no pressure is on hose. Install new caliper, remove bleed screw and fill with fluid. Then put bleeder screw back on and leave wrench on it. Then attach my Mityvac vacucme pump and build up pressure. Have a new banjo bolt ready to go with new washer on it and remove banjo bolt off old caliper, pop off washer on the underside, transfer it to the new caliper quickly with new bolt and washers, and then tighten quickly. Lastly, loosen bleed bolt right away to bleed.

My question is-the matter of seconds that is takes to transfer of hose, tighten up the bolt, and loosen the bleeder-would the little air that may get in, could it travel up to the abs module (like a air bubble at the bottom of a tube of water) or being brake fluid is somewhat thick do you think it would just kind of hover in place or travel slightly up the line but not far enough to get to the abs module?

To add to that I would remove the reservoir cap, put plastic wrap over the top and put cap back on to help keep any air from rising.

Trying to avoid having to take it to the stealership and pay the ridiculous cost of them bleeding the brakes with there tool to purge the air from the abs.


(This post was edited by Krokeefe0504 on Sep 17, 2021, 11:47 PM)


Tom Greenleaf
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Sep 18, 2021, 1:18 AM

Post #7 of 11 (335 views)
Re: Prevent air getting into abs module Sign In

No plastic at reservoir! The rubber in "masters" brake or for (not this) clutches is bellows to keep air out will lower with fluid level dropping.

Yes, you can be quick if you don't have pressure bleeder to push from master it would take luck + a helper knowing to push but not hit floor while you bleed out air and see it! If helper lets go while you at wheel are bleeding it out the game is lost or could be. Air sucks back in or can.

Certain ABS you'll get stuck to your "stealership" which isn't the intention, they have all tools to do it right or should.

You can lose your savings or win depends on proper helper and your speed at the wheel.

Other that can happen: Masters if and when pushed pedal to floor can fail from tearing rubber seals that make them work on crust where it hasn't travelled in years perhaps.

Moral of it: Be ready for plan "B" if it just doesn't work out despite all the attempts to prevent this from failing,

T



Hammer Time
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Sep 18, 2021, 3:38 AM

Post #8 of 11 (333 views)
Re: Prevent air getting into abs module Sign In


Quote
My question is-the matter of seconds that is takes to transfer of hose, tighten up the bolt, and loosen the bleeder-would the little air that may get in, could it travel up to the abs module (like a air bubble at the bottom of a tube of water) or being brake fluid is somewhat thick do you think it would just kind of hover in place or travel slightly up the line but not far enough to get to the abs module?


Your biggest concern in that situation would be how much fluid you would lose. Of course a little air will get in but it won't travel anywhere and the caliper is already full of air.. The concern is making sure the master doesn't go dry at any point. That is where the air will be introduced to the ABS. If you can quickly change the hose and banjo bolt that will work, as long as the master never goes empty. You will have to bleed a little but that air will come out right away.



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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.



Krokeefe0504
New User

Sep 18, 2021, 10:48 PM

Post #9 of 11 (318 views)
Re: Prevent air getting into abs module Sign In

Ok great, I was hoping whatever air entered during that short time wouldn't travel up to the abs module. I will have my vacumme pump ready to go so once I tighten the banjo bolt up I will start to vacate the air. Not finding anything online about pre-filling a caliper. Any knowledge on if that would work? With bleeder screw off and making a mini funnel or using tubing-not sure if fluid is too thick for it to enter the hole. Was going to give it a shot but thought I would ask.


Tom Greenleaf
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Sep 19, 2021, 12:06 AM

Post #10 of 11 (314 views)
Re: Prevent air getting into abs module Sign In

Just basics: Brake fluid, DOT 3 + 4 are pretty low viscosity = thin and go thru tiny holes of Banjo bolts and small hole at point end of bleeders.
Air seeks higher areas so placement of bleeder is highest in calipers but whole unit lower than the master? Many will gravity bleed. Stop and tap on calipers any are bubbles unseen like fizz in soda you see comes to top.
It's imperative bleeder's hole at bottom reaches the outlet end. Can use drill for most then blow thru.
Brake fluid is NOT oil! Note that. Oil products will ruin rubber quickly or over time.


Idea of this fluid is it doesn't boil if no moisture in it, doesn't freeze and is "hygroscopic" = (absorbs moisture) which ruins the boiling point of it at low %. New should be around 450F give or take.
One more: You can win. If pinching hose or hose was in trouble before some will make a bubble (hernia) type thing and soft brake pedal.
If seen - take care of that.


Good luck. Harder you try the better the results,
Tom



Hammer Time
Ultimate Carjunky / Moderator
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Sep 19, 2021, 3:15 AM

Post #11 of 11 (305 views)
Re: Prevent air getting into abs module Sign In


Quote
I will have my vacumme pump ready to go so once I tighten the banjo bolt up I will start to vacate the air.



Vacuum is not really the best way to go with this. It is far better to push fluid through than to pull it. One big flaw with vacuum bleeding is that you have to loosen the bleeder screw to do it and they then simply pull air through the threads. The best way to bleed is with a helper pumping the brake pedal and keeping the master full.

I always start with a gravity bleed. Just open the bleeder and let it drain until you stop seeing air and then pressure bleed what's left.



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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.







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