DJG Posted July 5, 2017 Share Posted July 5, 2017 Need some help a friend gave me a 1985 Mack dump truck to fix after he changed out a lot air valves the problem started with a bad brake chamber he replaced it with a new one and he told then air started leaking from the back left side relay so he changed them all but air still coming out of it when brakes are released. could the new air chamber be bad ? Quote Link to comment https://www.bigmacktrucks.com/topic/50381-air-leaking-from-left-back-relay-valve/ Share on other sites More sharing options...
alex g Posted July 5, 2017 Share Posted July 5, 2017 Tap that valve with a hammer to try to stop leak. If it at least slows down you'll know it's the problem.Sent from my SM-J320W8 using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/50381-air-leaking-from-left-back-relay-valve/#findComment-374190 Share on other sites More sharing options...
DJG Posted July 5, 2017 Author Share Posted July 5, 2017 Thanks, But he put two brand new valves on and it still leaks when the brakes are released. Quote Link to comment https://www.bigmacktrucks.com/topic/50381-air-leaking-from-left-back-relay-valve/#findComment-374194 Share on other sites More sharing options...
Vladislav Posted July 5, 2017 Share Posted July 5, 2017 Might be missmatch of hoses. You should look well over the piping diagramm to count out the issue. 1 Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/50381-air-leaking-from-left-back-relay-valve/#findComment-374200 Share on other sites More sharing options...
hatcity Posted July 5, 2017 Share Posted July 5, 2017 sorry, but that doesn't look like a new valve to me. check that all connections are tight 1 Quote Success is only a stones throw away.................................................................for a Palestinian Link to comment https://www.bigmacktrucks.com/topic/50381-air-leaking-from-left-back-relay-valve/#findComment-374201 Share on other sites More sharing options...
DJG Posted July 5, 2017 Author Share Posted July 5, 2017 they are new just old truck dropping sand all over every thing no air leaks all relay valves changed out and checked out the only air is coming out the vent on the left rear relay valve when brakes are released. checked hoses ok could it be a bad brake chamber leaking from one side to the other ? Quote Link to comment https://www.bigmacktrucks.com/topic/50381-air-leaking-from-left-back-relay-valve/#findComment-374202 Share on other sites More sharing options...
Freightrain Posted July 12, 2017 Share Posted July 12, 2017 Could be air chamber. Try removing the service line down to each chamber and release brakes and see if air comes out of one. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/50381-air-leaking-from-left-back-relay-valve/#findComment-374733 Share on other sites More sharing options...
DJG Posted July 14, 2017 Author Share Posted July 14, 2017 Ok Thanks, I will try that Quote Link to comment https://www.bigmacktrucks.com/topic/50381-air-leaking-from-left-back-relay-valve/#findComment-374888 Share on other sites More sharing options...
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