Mack58B42 Posted October 28, 2016 Share Posted October 28, 2016 All, I have an air leak in my B85, and I've tracked it down (or at least part of it) to this piece in the picture, which appears to be attached to an air manifold on the passenger side firewall. Air is coming out of the slit you can see where the plastic meets the metal, about 3/4" of an inch above (or to the left of, the way the pic is positioned) the number. I've Googled it, but can't find any info. to be able to replace it. Does anyone have any idea what it is, what it does, and where I might be able to find one? Quote Link to comment https://www.bigmacktrucks.com/topic/47473-b85-air-leak/ Share on other sites More sharing options...
Popular Post Freightrain Posted October 28, 2016 Popular Post Share Posted October 28, 2016 Air pressure switch. Likely for the low air light on the dash. By the markings it comes on at 60 psi which is about right. 3 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/47473-b85-air-leak/#findComment-350206 Share on other sites More sharing options...
HarryS Posted October 28, 2016 Share Posted October 28, 2016 I had to replace mine recently with a generic one from the local parts house. It cost somewhere around $5. Quote Link to comment https://www.bigmacktrucks.com/topic/47473-b85-air-leak/#findComment-350209 Share on other sites More sharing options...
39 Baby Mack Posted October 28, 2016 Share Posted October 28, 2016 Looks like a B&W (Bendix) switch, used to be two basic ones internally grounded or externally grounded Ron Sent from my SM-G900V using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/47473-b85-air-leak/#findComment-350220 Share on other sites More sharing options...
Mack58B42 Posted October 28, 2016 Author Share Posted October 28, 2016 Hmmm..... I have a buzzer in the cab that's constantly going off, and this may be why. Now that I know it's Bendix, I did some more research, and it looks like this particular model is no longer available, but they have a 279416N that looks like pretty much the same thing, so I have one on order.... Thanks!! Mike Quote Link to comment https://www.bigmacktrucks.com/topic/47473-b85-air-leak/#findComment-350228 Share on other sites More sharing options...
Maddog13407 Posted October 29, 2016 Share Posted October 29, 2016 (edited) yup, low pressure warning buzzer activation switch. replaced mine twice with new style like that one since I restored my truck 9 years ago. they last about one season of driving and the switch and buzzer quits workin again. the new ones are junk. the dump trucks and fire trucks had the switch mounted there, the road tractors had them wired to the tractor protection valve behind the cab. Edited October 29, 2016 by Maddog13407 1 Quote Link to comment https://www.bigmacktrucks.com/topic/47473-b85-air-leak/#findComment-350250 Share on other sites More sharing options...
Hobert62 Posted October 29, 2016 Share Posted October 29, 2016 Is there a reason why they weren't put inside the cab where the the light and buzzer are anyway? Quote Link to comment https://www.bigmacktrucks.com/topic/47473-b85-air-leak/#findComment-350258 Share on other sites More sharing options...
j hancock Posted October 29, 2016 Share Posted October 29, 2016 Wires are easier to run into the cab compared to copper or the new plastic air line. Certainly it could be done if you wanted. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/47473-b85-air-leak/#findComment-350281 Share on other sites More sharing options...
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