Xe18 Posted 14 hours ago Share Posted 14 hours ago (edited) I’m having this relay value leaking air from the bottom ( picture attached). Checked the valve with Mack dealer is around $600. Does anyone had experience with this issues? I saw one guy on YouTube saying replace the quick release valve first…. My truck is 2016 CXU613 . Thanks much. Edited 6 hours ago by Xe18 More pics Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/ Share on other sites More sharing options...
mechohaulic Posted 14 hours ago Share Posted 14 hours ago for $600.oo I would take the 4 bolts off the top . remove the alum plunger inside try for a rebuild kit which is nothing more than a 1/8th (+-) in square o=ring that goes on the plunger. a number of situation will give that valve air leak. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581070 Share on other sites More sharing options...
mechohaulic Posted 14 hours ago Share Posted 14 hours ago can't conceive the prices for this stuff today. 1k for a front brake can; 600 for a valve ???? Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581073 Share on other sites More sharing options...
Xe18 Posted 14 hours ago Author Share Posted 14 hours ago 14 minutes ago, mechohaulic said: for $600.oo I would take the 4 bolts off the top . remove the alum plunger inside try for a rebuild kit which is nothing more than a 1/8th (+-) in square o=ring that goes on the plunger. a number of situation will give that valve air leak. Can you able to share a rebuild kit part# ? Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581074 Share on other sites More sharing options...
mechohaulic Posted 14 hours ago Share Posted 14 hours ago where you have red circle is the exhaust potion of the valve(forgot to mention). good pair of snap ring pliers will remove bottom half which is flat rubber diaphragm /o-ring ? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581075 Share on other sites More sharing options...
mechohaulic Posted 14 hours ago Share Posted 14 hours ago 1 minute ago, Xe18 said: Can you able to share a rebuild kit part# ? Thanks numbers I don't have sorry. almost guarantee the small metal tag which would be on one of the four corner bolts is gone or unreadable, Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581076 Share on other sites More sharing options...
Joey Mack Posted 14 hours ago Share Posted 14 hours ago Is the data tag still on the valve? You may just have to remove it to I.D. it. Mechohaulic makes a good suggestion. At $600.00 i would take it apart and inspect it and clean it, and try to rebuild it. Is the air system Bendix or Wabco? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581077 Share on other sites More sharing options...
mechohaulic Posted 13 hours ago Share Posted 13 hours ago thanks for picture helps alot. but with all the electronic wires tied to it can't see the sides. if it's the service brake relay valve = the large line in front (green) is supply; 3/8 line on top is line from treadle/trolly which activates the valve; and there should be two more lines - one on each side going to brake chambers. inside plunger could be dry and sticking or bottom discharge valve has hole in diaphragm Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581078 Share on other sites More sharing options...
Joey Mack Posted 13 hours ago Share Posted 13 hours ago Its the ABS valve.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581079 Share on other sites More sharing options...
67RModel Posted 13 hours ago Share Posted 13 hours ago Did their price include installation or was that just for the part? Mack might be asking double what its worth. Get the part number off of it and see what one can be obtained for from an independent supplier. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581081 Share on other sites More sharing options...
Geoff Weeks Posted 12 hours ago Share Posted 12 hours ago 1st order of business is to make sure it is the valve that is bad. Remove the outlet hoses/piping and see if it stops leaking and air is coming back up a line from a defective brake chamber. Far better to find that out now, not after you have spent the $600 and wrestled it out of there. Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581086 Share on other sites More sharing options...
Geoff Weeks Posted 11 hours ago Share Posted 11 hours ago (edited) Hard to say for sure, but looks like this is the valve. Ad for picture ID only. https://www.ebay.com/itm/305180616028 Parts breakdown and procedure: BW2598.pdf Edited 11 hours ago by Geoff Weeks Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581093 Share on other sites More sharing options...
Joey Mack Posted 11 hours ago Share Posted 11 hours ago Looks like a basic R-12 valve between two ABS controllers to me.. if so they are cheap to buy 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581097 Share on other sites More sharing options...
Geoff Weeks Posted 11 hours ago Share Posted 11 hours ago Don't think it is,there is an electrical connection on the top from what I can see. Needs to be better I D to be sure. Looks an awful lot like a traction valve. I could be wrong. Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581098 Share on other sites More sharing options...
Joey Mack Posted 11 hours ago Share Posted 11 hours ago The valve in the link you posted is what i meant. His picture is not detailed enough,need to see other angles Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581099 Share on other sites More sharing options...
Geoff Weeks Posted 10 hours ago Share Posted 10 hours ago (edited) I think the two valves are more or less the same. The one with the solenoid on the top cover allows it to be used with traction control, the other is ABS only, as it requires treadle valve pressure to operate the relay portion and the ABS actuators are on the outlet. The ABS/traction control version allows the traction control to open the relay valve independent of the treadle valve, then the ABS controllers work and apply brake pressure to the spinning wheel and keeping it from the non spinning. The solenoid valve take tank pressure to operate the relay to "full open" while simultaneously preventing signal pressure back up the treadle valve line and out the exhaust at the treadle. regardless, I'd want to make sure none of the delivery lines are some how feeding air back up to the valve. Any air would vent out the exhaust of that valve giving the impression that the valve is "bad" when in reality it is doing what it is supposed to, vent any pressure from the brake lines when not called for by either the treadle valve or the traction control solenoid. Edited 10 hours ago by Geoff Weeks Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581100 Share on other sites More sharing options...
mechohaulic Posted 8 hours ago Share Posted 8 hours ago noticed no one questioned WHEN is the valve leaking ;; constant (shouldn't be) ; during service brake application or after service brake applied and released? might make a difference where the hunt starts. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581103 Share on other sites More sharing options...
Geoff Weeks Posted 8 hours ago Share Posted 8 hours ago I thought of asking, but a test of the output lines would give a good indication. Not being 100% sure of what the valve is hooked to, knowing when it leaks needs to know how it is used. K.I.S.S., if air is leaking back through the output, how the valve is used, is not important, it isn't the problem. Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581105 Share on other sites More sharing options...
Geoff Weeks Posted 8 hours ago Share Posted 8 hours ago In the pic, there is one line that appears to be hooked to the outlet of the relay that is not connected to a ABS modulating valve. Where does that one go? Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581106 Share on other sites More sharing options...
Joey Mack Posted 8 hours ago Share Posted 8 hours ago It seems to me he needs to chock the wheels air up the truck, release the brakes and pinch the drive axle service lines at each maxi to see if he has a bleedback going on. The maxi that stops the leak will have a bad diaphragm. Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581107 Share on other sites More sharing options...
Joey Mack Posted 8 hours ago Share Posted 8 hours ago Is that big line the supply, and the top one is the signal line ? Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581108 Share on other sites More sharing options...
Geoff Weeks Posted 7 hours ago Share Posted 7 hours ago The big "green" line closest to the camera should be supply. The 3/8" line near the top should be signal. It would appear the valve has 4 outlet ports, two on the side and 2 on the bottom. In the picture one of the bottom ports is plugged and it looks like the line I asked about goes into the other bottom outlet port. Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581109 Share on other sites More sharing options...
Geoff Weeks Posted 7 hours ago Share Posted 7 hours ago 22 minutes ago, Joey Mack said: The maxi that stops the leak will have a bad diaphragm. It will not be a diaphragm, they leak externally, it could be the O rings on the piston shaft of the maxi section, they can leak from spring brake air pressure into service brake side. Without knowing where the other line on the valve goes, I can't say what it could leak back. Might be inversion valve or anti-compounding. Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581110 Share on other sites More sharing options...
Joey Mack Posted 7 hours ago Share Posted 7 hours ago Ok.. im sorry. Im wrong about the diaphragm.. I guess all those times i was isolating a bad brake chamber was in error.. I will back out if this thread so as not to post incorrect statements. Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581111 Share on other sites More sharing options...
Geoff Weeks Posted 7 hours ago Share Posted 7 hours ago If it is infact the valve, most of the likely O rings and any dirt on the valve can be reached from below by removing the snap-ring and delivery valve. The O ring sizes are listed in the Bendix breakdown I posted. Quote Link to comment https://www.bigmacktrucks.com/topic/75877-relay-value/#findComment-581116 Share on other sites More sharing options...
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