Monk31 Posted December 3, 2015 Share Posted December 3, 2015 (edited) When I start truck up in the morning air leaks from the air dryer causing air pressure not to raise past 30psi . I give a few taps with a 3lb hammer and the air leaks stops and pressure builds up and will work for the rest of the day occasionally I will have to tap dryer after I had been shut down wondering why it is happen how to fix maybe or should I just replace Mack told me the carry a smaller air dryer in place of the old long air dryer I currently have and said some plumbing or air hose might have to be done . Any ideas or suggestions ? Thanks for any responses Sent from my iPhone using Tapatalk Edited December 3, 2015 by Monk31 Quote Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/ Share on other sites More sharing options...
thomastractorsvc Posted December 3, 2015 Share Posted December 3, 2015 probably an o ring is worn out Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314059 Share on other sites More sharing options...
Monk31 Posted December 3, 2015 Author Share Posted December 3, 2015 (edited) Where should I check for the worn out o ring ?Sent from my iPhone using Tapatalk Edited December 3, 2015 by Monk31 Quote Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314069 Share on other sites More sharing options...
farmer52 Posted December 3, 2015 Share Posted December 3, 2015 Can you hear air escaping from the dryer? What is the make/model of the air dryer? Bendix has rebuild parts available. Check with your dealer, contact Watt, or a truck parts supply house. Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314070 Share on other sites More sharing options...
Monk31 Posted December 3, 2015 Author Share Posted December 3, 2015 Yes I can hear air escaping from dryer. Not sure of make pretty sure it is Mack but it is discontinued according to dealer Sent from my iPhone using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314079 Share on other sites More sharing options...
farmer52 Posted December 3, 2015 Share Posted December 3, 2015 Post a pic of the dryer and where you think the air is leaking. Is the air leaking from a fitting, spitter valve, or ????? Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314083 Share on other sites More sharing options...
terry Posted December 4, 2015 Share Posted December 4, 2015 Yes I can hear air escaping from dryer. Not sure of make pretty sure it is Mack but it is discontinued according to dealerSent from my iPhone using TapatalkIf it is discontinued why not update to a new one? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314090 Share on other sites More sharing options...
thomastractorsvc Posted December 4, 2015 Share Posted December 4, 2015 How do you know that it is discontinued if you don't know what it is? Make\model I would bet that a rebuild kit is available if you took a picture and posted it to get it identified.If you can't post a picture for us to respond intelligently and help you than save the electrons and just replace it with a new one Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314093 Share on other sites More sharing options...
Monk31 Posted December 4, 2015 Author Share Posted December 4, 2015 Ok I will post picture tomorrow thanks Sent from my iPhone using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314103 Share on other sites More sharing options...
wilbur Posted December 6, 2015 Share Posted December 6, 2015 Its most likely from the pop off valve. You can get a bendix ad9 reman for 130.00 I would just change it. I change mine every 2 yrs Quote Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314442 Share on other sites More sharing options...
turckster Posted December 8, 2015 Share Posted December 8, 2015 As stated previously, the Bendix AD9 (reman) is a cheap alternative and they are good dryers. Another good dryer is the Bendix ADIP, it costs a little more than the AD9 but it has a spin on replacement desiccant filter. Much easier to replace than disassembling to replace a descant filter like on the AD9. Quote Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-314856 Share on other sites More sharing options...
Monk31 Posted December 13, 2015 Author Share Posted December 13, 2015 Thanks for the infoSent from my iPhone using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/42935-air-leak-from-air-dryer-in-1984-dm688sx-dump-tri-axle/#findComment-315586 Share on other sites More sharing options...
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