Brian L Blaylock Posted September 4, 2022 Share Posted September 4, 2022 can someone explain to me or post a diagram on how the air lines are connected to the tank and valve on a system with no maxi brakes I am running new lines and I’m not sure where they are supposed to be connected thanks Brian Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/ Share on other sites More sharing options...
Joey Mack Posted September 4, 2022 Share Posted September 4, 2022 are you putting trailer lines on a straight truck?? ie: dump truck.... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508534 Share on other sites More sharing options...
Brian L Blaylock Posted September 4, 2022 Author Share Posted September 4, 2022 No it’s a old semi trailer built before maxi brakes were required Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508536 Share on other sites More sharing options...
Joey Mack Posted September 4, 2022 Share Posted September 4, 2022 I have never converted one, i guess you could install a gladhand, and plumb it to a tank that you will install, there are brake valves that screw right into the center port on a generic air tank, that you can run park brake release lines from to maxi's that you will install in place of the single cans. an R-12 valve in conjunction with a QR-1 valve is also an option, it can be mounted on the frame rail or cross member, and do the same job.. I have diagram's.. I will try to post one, but I may not have enough MB's to do it.. give me a few minutes... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508539 Share on other sites More sharing options...
Brian L Blaylock Posted September 4, 2022 Author Share Posted September 4, 2022 It has air brakes on it now but they are service brakes only no maxi brakes I just bought it and the old lines were disconnected and I’m trying to figure out how to hook them back up Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508545 Share on other sites More sharing options...
Joey Mack Posted September 4, 2022 Share Posted September 4, 2022 ok,,, for some reason i cant get the picture loaded. PM me your cell # and I will text the diagram to you.... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508546 Share on other sites More sharing options...
High Binder Posted September 5, 2022 Share Posted September 5, 2022 This is all I have on file. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508547 Share on other sites More sharing options...
Joey Mack Posted September 5, 2022 Share Posted September 5, 2022 Oh hell. Are there wheels on the landing gear, so it can roll away when you try to hook it? 😅 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508558 Share on other sites More sharing options...
Brian L Blaylock Posted September 5, 2022 Author Share Posted September 5, 2022 No it’s a oil field float it’s made to let the nose down onto the ground the only landing gear is made out of pipe and folds up Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508585 Share on other sites More sharing options...
mrsmackpaul Posted September 5, 2022 Share Posted September 5, 2022 I have converted a few trailers to maxis, never converted it back though What lines are missing and from were ? Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508587 Share on other sites More sharing options...
Brian L Blaylock Posted September 5, 2022 Author Share Posted September 5, 2022 It never had maxis service brakes only both lines from the glad hands to the tank and distribution valve have been disconnected trying to figure out how they need to be hooked up Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508600 Share on other sites More sharing options...
D-Day Posted September 5, 2022 Share Posted September 5, 2022 Not sure what valve you have there are several different ones but this one is attached to the tank with a 1/2 inch pipe the port on the left is the service brake and the one in the center is charging the tank when the air is disconnected it applies the brakes in an emergency 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508617 Share on other sites More sharing options...
Brian L Blaylock Posted September 5, 2022 Author Share Posted September 5, 2022 So with this valve the air tank is filled through the valve? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508618 Share on other sites More sharing options...
Quickfarms Posted September 5, 2022 Share Posted September 5, 2022 The emergency, red, is connected to the tank with no valve to pressurize the tank the service, blue, is connected to the valve that is mounted on the tank. thr brake chambers are connected to the valve on the tank the valve on the tank serves as a relay since the service line does not produce enough air to operate the brakes by modern standards the maxi lines are connected directly to the tank the port location on the valve varies based on the valve Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508619 Share on other sites More sharing options...
Joey Mack Posted September 5, 2022 Share Posted September 5, 2022 (edited) part number 10500 Sealco... Air is supplied through another port, that valve screws to the tank is is fed directly, there is a brass filter screen inside the supply port.. many trailers have this valve... jojo Edited September 5, 2022 by Joey Mack more content needed 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508620 Share on other sites More sharing options...
Joey Mack Posted September 5, 2022 Share Posted September 5, 2022 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508622 Share on other sites More sharing options...
mrsmackpaul Posted September 5, 2022 Share Posted September 5, 2022 So I am trying to understand whats happened here The glad hands have been removed ? Is this correct? If so this is pretty simple, just hook the glad hands up either way it wont matter If they are the wrong way around nothing will happen when you push the button to charge the brakes, the button will stay in If they are the right way around you will hear air rushing back to fill the resevior on the trailer Many years ago I remember reading about a driver in the states that didn't know about this and the air lines were back to front The end result was people died as there was no trailer brakes yet the truck still drove many hundreds if not thousands of miles before it all went wrong I cant recall if the glad hands were wrong or badly worn or what the go was but it ended up the hoses were the wrong way around Apparently no tug test was ever performed at hook up Paul Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508625 Share on other sites More sharing options...
Brian L Blaylock Posted September 5, 2022 Author Share Posted September 5, 2022 Paul both of the lines were disconnected at the tank valve area I’m trying to figure out how to hook them up correctly Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508633 Share on other sites More sharing options...
mrsmackpaul Posted September 8, 2022 Share Posted September 8, 2022 So had a look at a trailer at my old (float) low loader last night and it doesn't have maxi's and it has this style valve signal goes in the top hole you can see Pretty sure this screws straight to the air tank How ever the air supply tees off on the way past at the tank and goes in the lower of the two holes A better diagram here These are the most common type that I have seen and used in Australia There is another type I have used as well Let me know if you need more or better information and I'll try and help Paul Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508812 Share on other sites More sharing options...
mechohaulic Posted September 8, 2022 Share Posted September 8, 2022 the old style trailer brake systems did NOT have maxi ( mechanical spring ) brakes . the single diaphragm can acted as a service brake and ALSO a parking brake. the magic was the valve it self. the valve screwed directly into the tank. brake application service side == air was directed through valve to brake cans. when disconnecting from trailer the brake valve closed an internal port and opened another sending air to the cans to hold brakes. imagine some little munchkin in the valve holding his foot on the port to keep air pressure going to cans, when the system lost it's air, "parking brake " was no more; resulting in trailers rolling away when fifth wheel backed under and landing gear came off the ground. that was the reason for the ridiculous procedure of back up to the trailer not touching the fifth wheel to trailer;; get out hook the hoses= charge the air system then apply trailer parking brake == then back under. even after the maxi can spring brake can was mandatory ; D O T inspectors made you follow the rule of the '40's/50'swhen going for CDL test. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508813 Share on other sites More sharing options...
mechohaulic Posted September 8, 2022 Share Posted September 8, 2022 if you are going to replumb this trailer with intent of running the road , law might say it must be done by todays standards meaning has to have spring brake parking brake. in that case clearance can be a situation requiring 24/24 cans . use to need two separate valves (R-8?R-6). modern technology must have a dual system valve set up; that can be effective yet simple for install. i wouldn't be concerned as to what it had but what will you need that will be safe and up to standards. good air tank, combo valve to screw directly in tank, 4 maxi cans or 2 maxi and 2 plain service cans . don't think anyone bothers with hose length vs hose size. should be 1/2 dia hose. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508814 Share on other sites More sharing options...
h67st Posted September 8, 2022 Share Posted September 8, 2022 I worked at a shoe company in the 80's and we were still running trailers with no maxis. We had a few roll away from the dock because the spotter got lazy and didn't chock the wheels (air leak = no brakes). 2 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508835 Share on other sites More sharing options...
fjh Posted September 8, 2022 Share Posted September 8, 2022 (edited) be wear ! The selco valve that Joey posted there comes in two versions not sure which number joe has posted there how ever! One will release the brakes on push of the button while it fills the tank / IF IT FILLS THE TANK ! And the other requires the tank to fill before the brakes will release! the later is the best one to install otherwise your trailer can run about with no air in that tank and you would never know! Not a safe condition ! Edited September 8, 2022 by fjh 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508837 Share on other sites More sharing options...
fjh Posted September 8, 2022 Share Posted September 8, 2022 (edited) 14 minutes ago, h67st said: I worked at a shoe company in the 80's and we were still running trailers with no maxis. We had a few roll away from the dock because the spotter got lazy and didn't chock the wheels (air leak = no brakes). In my mind there should be no trailers running around with out Spring brakes regardless of year! Same as tractors with spring brakes on only one axle which is still allowed by the way! You can always tell a cheap truck build if it was build with only one set of spring brakes it was a bottom of the line build! BARE MIN spec! Edited September 8, 2022 by fjh 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508838 Share on other sites More sharing options...
Joey Mack Posted September 8, 2022 Share Posted September 8, 2022 Sealco number 110500.. jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70395-trailer-brakes/#findComment-508843 Share on other sites More sharing options...
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