gra511 Posted February 11, 2013 Share Posted February 11, 2013 I have a 1986 rw613 with a E6 four valve engine 350. I have been noticing that when I park the truck ,with the engine off ,with out setting the brakes, air starts leaking out of the valve out of that little hole. It usually takes about 3-4 minutes then the parking brakes lock up. Is this normal? I tried this a couple of times and noticed as the air was leaking from the valve on the manifold, air was leaking from the relay valve on the parking brakes.The air at both places stopped as soon as the brakes locked up. Hints or suggestions greatly appreciated. Quote Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/ Share on other sites More sharing options...
smorse54 Posted February 11, 2013 Share Posted February 11, 2013 It is normal for the reversing relay to leak a small amount. it sounds like you also have a leaking problem with the parking relay valve.I would fix that first then check the reversing relay. Steve Quote Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-163531 Share on other sites More sharing options...
rsb502 Posted February 12, 2013 Share Posted February 12, 2013 ABOVE is true, and why are you parking without setting the parking brake? Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-163790 Share on other sites More sharing options...
gra511 Posted February 12, 2013 Author Share Posted February 12, 2013 I was adjusting a slack adjuster,I had the wheel;s blocked. The air was rushing out the relay so hard that I had to rush the adjustment. That is when I noticed the relay valve on the axle was leaking at the exhaust part of the valve. Thanks for the suggestions. Quote Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-163817 Share on other sites More sharing options...
rsb502 Posted February 12, 2013 Share Posted February 12, 2013 ok so a quick release valve on the rear brakes was leaking, that makes more sense, if the quick release valve is leaking its not that hard to swap and its not that expensive, however it may be a bad brake chamber bleeding back thru the valve. If the brakes are released and air is coming out of the vent on the bottom of the valve in the frame or on the axle for the service side more times than not one of your 30-30 brake chambers has a bad pancake letting the air flow to the service side of the brakes and vent out the quick release, if its the emergency brake valve leaking its more than likely the valve, make sure which it is, chambers should be marked at the ports and you can follow the lines if you dont know off the top of your head, emergency just has a small quick release vcalve on the axle on most RW's, service has a small one on the axle and a larger brake relay valve in the frame near each axle. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-163837 Share on other sites More sharing options...
rsb502 Posted February 12, 2013 Share Posted February 12, 2013 oh yeah you said "on the axle" above, oops oh well the above still applies, is it the service qr2 or the emergency qr2? then go from there if its the emergency swap the qr2 if its the service check your chambers on that axle by removing the hoses from that qr2 valve on will have air coming from a brake chamber, that brake chamber is bad. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-163839 Share on other sites More sharing options...
gra511 Posted February 13, 2013 Author Share Posted February 13, 2013 It is the service relay that is leaking , and I would be positive that the pancake is old enough to go bad. But can the reversing relay on the manifold be bad? Like I previously mentioned,when the truck is shut off without the brakes set, that valve leaks air so bad you could blow up balloons with it. And with the brakes set nothing happens. Thanks for the brake trouble shooting tip, Iam sure others will appreciate the advice. Quote Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-164045 Share on other sites More sharing options...
smorse54 Posted February 13, 2013 Share Posted February 13, 2013 It is normal for the reversing relay to bleed a minute amount if air when the parking brake is not applied.If it is blowing lots of air yes it's bad. Steve Quote Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-164061 Share on other sites More sharing options...
rsb502 Posted February 14, 2013 Share Posted February 14, 2013 Like I said if there is air leaking with the brakes released its probably a bad brake chamber, there is no pressure application difference on the relay valve until you push the brake pedal. Go to the small quick release valve mounted on the axle between the brake chambers on the service side, it will have one air line in from the relay valve and two air lines out to the chambers. Remove the lines that go to the chambers and then push in the dash valve to release the brakes, one of them will have air coming out of it if you have a bad chamber, it costs nothing to prove me wrong. From what you are describing it almost has to be the issue, unless your pulling the hand valve down in that case there are other possible but you have not mentioned that in this thread so I'm guessing you have it in gear brake valve in hand valve released. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-164267 Share on other sites More sharing options...
rsb502 Posted February 14, 2013 Share Posted February 14, 2013 Just looked at an old mack book, it says the same thing if there's air coming out of the service side when the emergency side is released check for back flow from emergency side thru the chambers and qr valves. If the relay valve leaks with the brakes applied reseal or replace the valve Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-164268 Share on other sites More sharing options...
gra511 Posted March 29, 2013 Author Share Posted March 29, 2013 Replaced reversing relay on the intake manifold,no more air leaks. I ordered it at Watt's for around 240 bucks. I took the old one apart andthe relay has 2 teflon looking washers inside of it that went bad. The brakes are fine. Quote Link to comment https://www.bigmacktrucks.com/topic/29893-reversing-relay/#findComment-174841 Share on other sites More sharing options...
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