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leaving
Novice
Nov 13, 2012, 1:29 PM
Post #1 of 16
(2508 views)
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Can't bleed brakes
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1998 GMC Jimmy 4 x 4 4.3 liter engine 170,000 miles Rear brake master cylinder chamber went dry and got air in the system. Bleed master cylinder and tried to bleed rear brakes. I can get no pressure / fluid to the rear calipers. I blew out break lines to make sure they were not plugged. Discovered that I can get pressure / fluid at the ABS pump inlet but nothing at the ABS pump outlet going to the rear. Any ideas? Thanks in advance! Joey
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Discretesignals
Ultimate Carjunky
/ Moderator
Nov 13, 2012, 2:22 PM
Post #2 of 16
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Re: Can't bleed brakes
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What was the reason for the master being empty? Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Nov 13, 2012, 2:24 PM)
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leaving
Novice
Nov 13, 2012, 2:29 PM
Post #3 of 16
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Re: Can't bleed brakes
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I could not find any leaks. I had replaced the calipers a month or so ago and maybe I did not bleed the brakes well...not sure but I am certain there are no leaks. Also replaced the master at that time. Additional note...I have tried a vacuum bleed system as well as a pressure bleed system with no luck. Afraid that my ABS pump is bad but don't know how to diagnose. Thanks!
(This post was edited by JoeyGrissom on Nov 13, 2012, 2:32 PM)
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 13, 2012, 2:32 PM
Post #4 of 16
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Re: Can't bleed brakes
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Not bleeding the brakes doesn't make fluid disappear. You have a leak somewhere. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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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leaving
Novice
Nov 13, 2012, 2:41 PM
Post #5 of 16
(2423 views)
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Re: Can't bleed brakes
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Have no idea...I was guessing that air in the lines moved into the master. All I know is that I have pressure tested the whole system and no leaks to be found anywhere.
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 13, 2012, 3:51 PM
Post #6 of 16
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Re: Can't bleed brakes
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Don't look for liquid. Look for dark stains, especially from the booster. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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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leaving
Novice
Nov 13, 2012, 5:04 PM
Post #7 of 16
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Re: Can't bleed brakes
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After I filled the master back up, the level never went down again. So I may have had a leak but it is not leaking now. Anyway, my real concern is why I cannot get fluid / pressure from the ABS pump outlet leading to the rear brakes. I have strong pressure leading to the ABS rear brake inlet but it will not pass through the pump. That is the real issue I'm having. Thanks!
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 13, 2012, 5:07 PM
Post #8 of 16
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Re: Can't bleed brakes
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It doesn't work that way. you won't see the level drop because you aren't looking for anything that fast. you have a leak, find it before going any further. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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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leaving
Novice
Nov 13, 2012, 5:17 PM
Post #9 of 16
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Re: Can't bleed brakes
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I filled it up a month ago and the level has not dropped since. Maybe I left a bleed valve loose of something. I'm not sure. The point is that it is not leaking now. I have pressure tested the system and I can find no leaks. But lets assume I do. I can keep working on that part. What I'm really concerned about is the ABS pump. I may be wrong but I don't know how a minor slow leak would have anything to do with fluid not passing through the pump. This is the issue that I really need some help / advise with. Thanks again!
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nickwarner
Veteran
/ Moderator
Nov 13, 2012, 8:05 PM
Post #10 of 16
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Re: Can't bleed brakes
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You would need a tech-level scan tool that has the ability to actuate the ABS in order to test it for function and to properly bleed the system.
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 13, 2012, 8:18 PM
Post #11 of 16
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Re: Can't bleed brakes
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Yeah, it makes a whole lot of sense to go through all the hassle to get the system bled and them find the failure that caused the issue in the first place and start all over. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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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nickwarner
Veteran
/ Moderator
Nov 13, 2012, 8:25 PM
Post #12 of 16
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Re: Can't bleed brakes
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Doesn't make much more sense to try to diagnose and repair a system if you aren't equipped to be able to finish the job either, does it?
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 13, 2012, 8:28 PM
Post #13 of 16
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Re: Can't bleed brakes
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Yep, that would be a very good reason to get it to a professional that knows what he's doing as you should have done in the first place. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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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leaving
Novice
Nov 13, 2012, 8:53 PM
Post #14 of 16
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Re: Can't bleed brakes
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So I guess what you are saying is that you have no clue what could cause my problem either! Hehe! Yeah I already knew what you guys have covered. I guess I had my hopes too high thinking someone might have seen this before and had some beneficial suggestions. Thanks anyways... Maybe someone else might see this that has experience with this type of problem. Thanks Joey
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nickwarner
Veteran
/ Moderator
Nov 13, 2012, 9:15 PM
Post #15 of 16
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Re: Can't bleed brakes
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We know your problem. You have shown yourself inept to locate it. There isn't a roving tribe of ninjas creeping in and stealing brake fluid out of your car. It went somewhere. When fluid gets out of a sealed system, thats called a leak. You have yet to find the leak. Even if you did, it wouldn't do you an ounce of good because without a tech-level scan tool you can't bleed your brakes thanks to that pesky ABS setup you said you had no clue how to diagnose. Have fun with that, you seem to not need our help anymore.
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