phoenix2013 Posted March 18, 2015 Report Share Posted March 18, 2015 There is a brakes thread already on this forum but I felt that this in itself might be useful to others as it demonstrates the thought process in troubleshooting a problem with a fifths brakes and a fact that what the seller of the fifth tells you might not necessarily be the “truth, the whole truth and nothing but the truth”. Let me open with few givens: I fixed the problem sight unseen, on the telephone. I still don’t know the make of the fifth. I didn’t ask if it was a private sale or a dealer sale. I received a frantic call from a client of mine, a Jackalopee owner. “I am on the side of the road; I pulled over because the fifth brakes are smoking, blue smoke” “Did you check the emergency pull cable; is it pulled out by any chance”? “No, it’s in there and looks fine” “Pull it out and reseat it and see if the brakes release” Customer goes away to perform the “procedure”. “No, it’s still locked up and it’s all wheels I can see them dragging furrows in the grass on the side of the road” “What kind of brakes you have, electric, or electric over hydraulic”? “Disk brakes” “What kind of brake controller are you using”? “Brake controller”? “Yeah, the brake controller in the cab” “I don’t have any” “Don’t have any, what controls the hydraulic actuator for the disk brakes”? I get some sort of noncommittal answer that he was told that it was not necessary, they work by themselves…… “Yea, they have hydraulic surge brakes, but I have never seen these on a fifth. You have to have something in the truck to tell the hydraulic actuator to activate the brakes; it will not do it just by itself. How is the Jackalopee wired, is there anything connected to the BRAKE CONTROLLER tab”? “No, there is nothing on that tab, by the way the Jackalopee works great” “Can you see what you have for the hydraulic actuator in the fifth, it should be in the front compartment, about a size of a shoe box with a hydraulic ¼” line coming out of it and some wires going to it”. Customer goes to look. “I have lots of hydraulics but these are for the hydraulic rooms’ extenders, nothing that looks like what you describe” Hmm, stranger and stranger. “Whose disks you have on the fifth, Dexter or Kodiak” “I don’t know, the axles are Alco” Hmm, stranger again, I didn’t think Alco axles were typically supplied with disk brakes. “Can you go look under the fifth an see if there are hydraulic lines going to the brakes” Customer climbs under the fifth with the cell phone. “No, there are no hydraulic lines, only wires going to each wheel” “Looks like you’ve been told a bit of BS, you don’t have hydraulic brakes you have plain electrics and with no controller in the cab you never had brakes on the fifth, how much does your fifth weigh”? “About 13,000 pounds” “With an HDT it’s like nothing, it didn’t need the brakes on the fifth” “What about the lockup”? “There is nothing connected to your brakes other than the emergency circuit, there are two wires going to it, one connected to the fifth battery, the other to the brakes, you won’t be able to tell the difference, so cut them both and insulate well the ends. Cut one at a time, not through both at the same time, let me know what happens”? I get a phone call half hour later. “The brakes are free, thanks a lot, I’m on the way to the Escapees Rally, will have it taken care of there”! Link to comment Share on other sites More sharing options...
spindrift Posted March 18, 2015 Report Share Posted March 18, 2015 Not sure I understand what caused the brakes to lock up...all of a sudden. 2012 F350 KR CC DRW w/ some stuff 2019 Arctic Fox 32-5MCindy and Tom, Kasey and Maggie (our Newfie and Berner) Oh...I forgot the five kids. Link to comment Share on other sites More sharing options...
phoenix2013 Posted March 18, 2015 Author Report Share Posted March 18, 2015 Bad emergency stop switch, once it was cut out of the brake circuits, the brakes released. Link to comment Share on other sites More sharing options...
stolpsaddles Posted March 19, 2015 Report Share Posted March 19, 2015 Will have to remember this one. I have had a couple of trailers that the brakes would activate with the signal or brake lights being activated, found out that a bad ground can back feed through the brakes and fully activate them. 2005 Western Star, MDE 4000 ,singled mid, 12' deck with Smart CarBison Stratus 3 horse with 16' short wall 12' slide out http://www.spottedhorsegallery.com/http://www.campingandhorses.com/ Link to comment Share on other sites More sharing options...
Newt Posted March 19, 2015 Report Share Posted March 19, 2015 Will have to remember this one. I have had a couple of trailers that the brakes would activate with the signal or brake lights being activated, found out that a bad ground can back feed through the brakes and fully activate them. It has been my experience that a bad ground on trailer 12V electrical systems can cause problems that to me are unexplainable. It will do weird things. But, fix the ground and everything all of a sudden works. Newt 2012 HitchHiker Discover America 345 LKSB 2009 Dodge/Cummins LIVINGSTON TX Link to comment Share on other sites More sharing options...
peety3 Posted March 19, 2015 Report Share Posted March 19, 2015 Will have to remember this one. I have had a couple of trailers that the brakes would activate with the signal or brake lights being activated, found out that a bad ground can back feed through the brakes and fully activate them. Apparently a variety of switches decide to switch off by going to ground, rather than going to an open circuit. And yes, if two circuits are tied to ground, but the ground isn't really at ground, circuit 1 feeds to "ground" which feeds back through circuit 2 to ground, causing this behavior. As an electrical engineer (by degree only), I can't imagine why anyone would bother to tie "off" to ground instead of leaving it open. Nonetheless, I see the classic "marker light goes out in conjunction with the flash of the forward turn signal", and I've also read about some pro audio gear (mixing consoles, to be specific) which had vastly improved noise specs by having certain switches tie to ground instead of open. *shrug* Link to comment Share on other sites More sharing options...
phoenix2013 Posted March 19, 2015 Author Report Share Posted March 19, 2015 Typical (read cheap) breakaway switch has one wire going to the fifth batteries and the other to the the brakes "blue wire". Both wired to the 1/4 inch audio jack NORMALLY CLOSED terminals. Shoving the 1/4 inch plug into the jack keeps those terminals open. Pull the plug out and they close putting full battery power onto the blue brake wire, locking these up. It's puzzling to me how these can short internally, but this was the case in the above instance. Link to comment Share on other sites More sharing options...
Refuzn-To-Grow-Up Posted March 19, 2015 Report Share Posted March 19, 2015 Sad that someone sold him a line of BS. Had he come down a steep winding mountain road it could have ended tragically, but for the HDT. One of my first trips, with the HDT, was going down a 6% grade, with many switch backs. I was on the Jake brake all the way down. When we got back, I put the trailer in for service, for the first time. When hubs were pulled, we discovered that three of the brake hubs (I have a three axle trailer) were loaded up with grease, from the dealer prep guy going crazy with the grease gun. So, I only had three functioning trailer brakes. Had I been in the Ford F-550, we would have gone over the side of the mountain! The HDT is the only really safe way to come down a steep mountain, but I am preaching to the choir. Link to comment Share on other sites More sharing options...
noteven Posted March 19, 2015 Report Share Posted March 19, 2015 An issue I have with eeelectric brakes is you can have a non-functioning wheel or two in a group of six and have no idea really unless you like to skid test your $400 steel casing tires - until you really need them to whoa up ... I think my DirecLink controller shows a trouble if there is a faulty brake... not 100% sure "Are we there yet?" asked no motorcycle rider, ever. Link to comment Share on other sites More sharing options...
noteven Posted March 19, 2015 Report Share Posted March 19, 2015 Hi Bill B - I sometimes ponder what would be involved in running axles with normal ABS air brakes on a rv 5th wheel trailer I even caught myself looking at low profile axles with air brakes on line the other day "Are we there yet?" asked no motorcycle rider, ever. Link to comment Share on other sites More sharing options...
phoenix2013 Posted March 19, 2015 Author Report Share Posted March 19, 2015 Link to comment Share on other sites More sharing options...
Broncohauler Posted March 20, 2015 Report Share Posted March 20, 2015 Typical (read cheap) breakaway switch has one wire going to the fifth batteries and the other to the the brakes "blue wire". Both wired to the 1/4 inch audio jack NORMALLY CLOSED terminals. Shoving the 1/4 inch plug into the jack keeps those terminals open. Pull the plug out and they close putting full battery power onto the blue brake wire, locking these up. It's puzzling to me how these can short internally, but this was the case in the above instance.. Thanks for the explanation never knew how the breakaway switch work before Link to comment Share on other sites More sharing options...
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