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berkeleydude
Active Member
17 Posts |
Posted - 02/08/2017 : 09:08:51 AM
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99 BLUEBIRD 77 PASS . PP1 PUSHED IN DRAIN SECONDARY APPLY PEDAL PRIMARY DROPS AND SECONDARY FILLS UP, BUS NOT RUNNING FRUSTRATED AND NEED ADVICE. FIRST THOUGHT WAS DOUBLE CHECK VALVE,REPLACED IT SAME ISSUE |
Edited by - berkeleydude on 02/08/2017 10:27:00 AM
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krmvcs
Advanced Member
362 Posts |
Posted - 02/08/2017 : 10:59:19 AM
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Treadle or SR-1 valve? Does it do this on the other tank as well? |
-Ken- |
Edited by - krmvcs on 02/08/2017 10:59:54 AM |
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berkeleydude
Active Member
17 Posts |
Posted - 02/08/2017 : 11:00:23 AM
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ONLY DOES IT ON ONE TANK |
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krmvcs
Advanced Member
362 Posts |
Posted - 02/08/2017 : 11:24:35 AM
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well theres only so many ways for air to get back to an empty tank. if the SR-1 valve works as it should then it looks like youre gonna have to start removing hoses until you find your problem. AND STOP YELLING!!! :) |
-Ken- |
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berkeleydude
Active Member
17 Posts |
Posted - 02/08/2017 : 12:41:20 PM
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didnt notice caps lock was on, my bad. thanks for the advice |
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40ngone
Senior Member
USA
166 Posts |
Posted - 02/08/2017 : 2:23:20 PM
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I am going to ask what may seem to be an obvious question, but I have to ask. When you say secondary and primary, you are meaning secondary is the front, primary is the rear, correct? Again, I don't mean to offend, but have seen much misunderstanding. |
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berkeleydude
Active Member
17 Posts |
Posted - 02/09/2017 : 06:07:17 AM
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yes, meaning secondary is front and primary is rear. this shop does not have ANY reference material whatsoever.... i guess we are supposed to commit every system/subsystem to memory for every vehicle in the fleet |
Edited by - berkeleydude on 02/09/2017 07:03:44 AM |
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40ngone
Senior Member
USA
166 Posts |
Posted - 02/09/2017 : 08:57:17 AM
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Has this bus had any recent components changed in the air system that could of possibly been installed wrong?? |
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berkeleydude
Active Member
17 Posts |
Posted - 02/09/2017 : 09:11:57 AM
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no new components, just all of a sudden. driver reported issue during pre-trip splitting tanks |
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berkeleydude
Active Member
17 Posts |
Posted - 02/10/2017 : 2:17:06 PM
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for kicks i replaced every check valve at every tank, still same issue how is this possible? |
Edited by - berkeleydude on 02/10/2017 2:21:21 PM |
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krmvcs
Advanced Member
362 Posts |
Posted - 02/10/2017 : 3:24:43 PM
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You shouldnt have check valves on the tank outlets. And this problem of yours is likely an internal leak in one of the valves. On the generic split system diagram the only 2 possibilities are the treadle and the SR-2. The other one that comes to mind if you have it, might be the anti compound check valve on the rear relay valve. |
-Ken- |
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berkeleydude
Active Member
17 Posts |
Posted - 02/10/2017 : 5:12:53 PM
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i will crack lines and see whats going on. thanks |
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BJ Henderson
Advanced Member
USA
280 Posts |
Posted - 02/13/2017 : 10:06:33 PM
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Treadle valve is most likely problem. If the driver is doing a leakdown test and this is happening. Unless it has a straight truck valve on it.
Disconnect lines from treadle valve while duplicating problem. |
CMTT,CMAT,CMBT |
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40ngone
Senior Member
USA
166 Posts |
Posted - 02/14/2017 : 08:28:53 AM
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Berkeleydude, Are you saying that the primary and secondary are trying to equalize? When brake is applied in description, are any of the brake being applied at the wheels, or attempting to? |
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berkeleydude
Active Member
17 Posts |
Posted - 02/16/2017 : 09:02:12 AM
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replaced treadle valve, same issue....quote: Originally posted by BJ Henderson
Treadle valve is most likely problem. If the driver is doing a leakdown test and this is happening. Unless it has a straight truck valve on it.
Disconnect lines from treadle valve while duplicating problem.
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berkeleydude
Active Member
17 Posts |
Posted - 02/16/2017 : 10:00:40 AM
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maybe some fire will fix this thing.....jk |
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40ngone
Senior Member
USA
166 Posts |
Posted - 02/16/2017 : 1:29:59 PM
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My thoughts are that two lines have been installed in the wrong location. I don't see this happening through any normal part failure. It would be a rare situation. I would start running down the air lines one at a time to verify that they are in the correct locations. |
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BJ Henderson
Advanced Member
USA
280 Posts |
Posted - 02/18/2017 : 09:12:52 AM
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Did you disconnect lines from the brake side of the treadle valve while duplicating problem? If you did not, you did not check to see if back pressure is feeding from a valve somewhere. Good thing to check also is what someone else said, see if some lines are crossed. If the problem has not changed from the original complaint, you have not had any change whatsoever in the defect? https://www.google.com/search?q=bendix+air+brakes+troubleshooting&ie=utf-8&oe=utf-8 Here, download this, it might be of help to you in the future. |
CMTT,CMAT,CMBT |
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BJ Henderson
Advanced Member
USA
280 Posts |
Posted - 02/18/2017 : 09:17:40 AM
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Oh yeah, come back and post what you find when you locate the problem. The only way this works good is sharing knowledge. |
CMTT,CMAT,CMBT |
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berkeleydude
Active Member
17 Posts |
Posted - 02/22/2017 : 08:52:35 AM
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a tear in a $1.00 oring on the R12 valve was the culprit. thanks for all the advice |
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