Trailer Brake Adjustment?

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   Hey Offgrid,

I'm back to tracking with you.  The magnets could be an issue, so again good luck.

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mcarter Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 07 Apr 2016 Location: Greenbrier, TN Online Status: Offline Posts: 3419	Topic: Trailer Brake Adjustment? Posted: 11 Oct 2018 at 5:13pm
	Hey Offgrid, I'm back to tracking with you. The magnets could be an issue, so again good luck.
	Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability."

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 14 Oct 2018 at 7:07am
	I just got back to the OBX, had to wait a couple days for the water levels from Michael to drop. Not driving the rPod thorough salt water, the rust resistance of the trailer frames is a joke. I took a couple of preliminary current readings on the brake magnets. At a setting of about 11 on the brake controller I got about 3A on the pass side and 3.5 on the drivers side. Interestingly, cranked up to full at 13 the drivers side went up to about 4A as you would expect but the pass side went down to about 2.5A. Note that both readings are about 6.5A combined, which is as it should be according to Lippert's troubleshooting guide. So I definitely have an imbalance, which is consistent with what I'm seeing with brake heating between the two sides. Note that the entire brake assemblies on both wheels are brand new, including the magnets. Also, the brakes I replaced had significantly more wear on the drivers side, and that side tended to grab frequently. So I think it's likely not the magnets, more likely it's a wiring issue, with more resistance in the pass side circuit. The current going down to the pass side brake magnet at higher voltage is a puzzler to me though. I'll break the connections at both magnets next and measure the resistance to each directly. I can also check the wiring resistance to each side by shorting the leads back to the trailer plug one at a time.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold

mcarter Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 07 Apr 2016 Location: Greenbrier, TN Online Status: Offline Posts: 3419	Posted: 14 Oct 2018 at 10:41am
	here is a link to the etrailer procedures if it is of use to you. https://www.etrailer.com/faq-testing-trailer-brake-magnets-for-proper-function.aspx
	Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability."

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 14 Oct 2018 at 11:43am
	Yeah mcarter I saw that test guide. Interesting that Etrailer says current for 2 brakes should be 7.5-8.2A but Lippert says 6A. So Im not out of spec (for two) for Lippert but I am for Etrailer. Hmmm.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold

GlueGuy Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 15 May 2017 Location: N. California Online Status: Offline Posts: 2628	Posted: 14 Oct 2018 at 12:15pm
	I would also check the voltage drop when the brakes are applied at different settings. If one is showing ~~ 10V (for example) at the input to the brake magnet, and the other one is showing 9V (for example), then you know that you either have a delivery problem (AKA wiring issue), or a coil problem. If the voltage applied is different, you might want to check the resistance of the coil. What I'm thinking is you may have a high-resistance connection or a bad coil. I suppose the other option to eliminate one or the other would be to get your hands on a power resistor (~~ 3-6 ohms or something like that), and put that in the circuit in lieu of the actual brake coil. Then you could test the brakes to see if the current supplied to both sides was the same.
	bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 14 Oct 2018 at 2:46pm
	I'm having a hard time believing its a bad magnet since these are brand new brake assemblies and I was having more brake action on the drivers side with the old brakes as well. The other thing that makes me a bit suspicious is that there are 3 wires in each of the drivers side brake splice connectors but only two in the pass side, implying that the pass side is probably being fed across from the drivers side, so more line length and connectors to the pass side. They're also all those crappy "insulation displacement" connectors that FR and Lippert use everywhere. I might just get under there and replace all the brake splices with solder and heat shrink while I'm at it, just because.... But it could be two bad magnets in a row on the same side, stranger things have happened. I think I should see the line resistance difference if its there by directly measuring it at the trailer connector with the wires to each brake magnet shorted together one wheel at a time. There ought to be about an ohm or two difference between the two sides to account for the difference I'm seeing. If not then the power resistor in circuit is an interesting idea. Not sure I still have one or where it would be if I did, so I might also try swapping the brake wires from one magnet to the other with some jumper wire and see what that looks like. I'll provide an update after I do the tests tomorrow.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 15 Oct 2018 at 4:35pm
	Well i spent a bit of time today on this. First I got distracted by my brake lights being on when I used the manual slide on the prodigy p2. I thought I might have a shorted wire in the harness somewhere. Called etrailer and talked to a tech, apparently all brake controllers are designed that way now thanks to a rule in the PRC (People's Republic of California) requiring brake lights to be on whenever any brakes are applied, even manually. Didn't know that... Then I checked the voltages and currents carefully on both brakes at several controller settings. The voltage is about 0.2V lower on the pass side because of the longer leads going over there from the drivers side, about what one might expect for that current level and wire gauge. But that's not enough to explain the current difference between the two sides. Turns out there is a ground fault on the pass side brake somewhere. The current difference between the two leads on that brake magnet is well over half an amp at full voltage, zero on the driver's side. The pass side brake also buzzes noticeably while the drivers side does not. The reason I saw the puzzling drop in current before when I increased the controller voltage is because I must have changed leads I was measuring between the two readings. So at least that is explained. So I guess I'm a victim of Murphy's law and got two bad brake magnets in a row on the same side of the trailer. I guess the next step is to buy a new magnet and swap them on the pass side. I don't know that I need to change the driver's side too since the whole brake system is new less than 800 miles ago. What do you think? I still think I'm still going to also rewire the whole trailer brake system using home runs of heavier gauge wire and also add a junction box to make it easier to troubleshoot problems in the future.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold

mcarter Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 07 Apr 2016 Location: Greenbrier, TN Online Status: Offline Posts: 3419	Posted: 15 Oct 2018 at 4:40pm
	offgrid, Stranger things have happened. I know in the world of auto repair, it is amazing how many bad parts I got. On your magnets, the one that is working - leave it alone -:) Last thing you need is another bad magnet put in where working magnet was. I would concentrate on the problem side and toast success on the other.
	Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability."

offgrid Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 23 Jul 2018 Online Status: Offline Posts: 5290	Posted: 15 Oct 2018 at 4:49pm
	Roger that mcarter, and good point about the quality of replacement parts these days. The Lippert branded stuff all shipped from China for what it's worth. Just as an aside, I know you probably think I was being anally retentive checking my brake drum temps with the ir thermometer like I was but if I hadn't done that I doubt I would have identified that I had a problem until I burnt up another set of brakes, as the basic checks I did of both magnets together during installation were within the normal operating range.
	1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold

mcarter Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 07 Apr 2016 Location: Greenbrier, TN Online Status: Offline Posts: 3419	Posted: 15 Oct 2018 at 5:12pm
	Offgrid, Truthfully I think you are being good at what you're good at, using what you know and I can't fault that.
	Mike Carter 2015 178 " I had the right to remain silent, I just didn't have the ability."