1979 Burro - Electric brakes

[Herb P]

Also.. How can I test my brakes as they are now. I have the 2 wires sticking out the back of the hub and I can get 12volt from battery to them. Is there a way to test them or is straight 12volts to much?

A new axle with brakes is going to cost a bunch of money that you may not need to spend... The brakes are really simple in theory... There's no magic there... If you can get power to the electromagnet, then the rest is all mechanical and can be worked from the comfort of a milk crate with the drum off...

The way I tested my brakes for basic operation was to jack up one wheel at a time, spin it like crazy, and then slide the manual lever of my brake controller... After a short scraping noise, the wheel stopped spinning. Since you don't have any of that hooked up, I would think 12V is not too much to apply to it for testing (I don't think I've seen my brake controller apply more than 8 or so volts)... It's an electromagnet so I don't believe polarity is important unless one side is grounded

Frankly, I would inspect the pads... If they have any meat on them whatsoever, they're probably fine (unless they've gotten greasy. Never handle brake pads with oily or greasy hands)... Check the drums, if they're not excessively scored, they're probably fine as well... The drums should (probably) have a number cast into them somewhere.. That number is the maximum diameter of the drum... If they're scored but still within tolerance, you can get the drums turned for about $10 at your local brake shop.. Or you can just take them to the brake shop and have them inspect the drums... Personally, I avoid having drums/discs turned because it just removes needless 'meat' which increases the likelihood of warping...

Once you confirm basic function, I would simply run new wire to the trailer connector... The higher the gauge, the better, in my opinion but I think 12ga is probably a reasonable thickness... There's not much current flowing through the brake wires so loss is not that much of an issue.

btw, my highly sarcastic post earlier in the thread was intended as levity towards Brian which apparently was taken correctly by Brian but others took offense for some reason... My point (and Brians probably) stands.. Any wiring outside the trailer needs to be secured, sheathed, and sealed. Those wires are dangling, that means they're rubbing (one of those wires goes through a hole on the axle hanger, that hole probably has sharp edges). If you look in the end of those blue splice connectors, you will see a metal blade that has pierced the insulation on the wire. If you can see it, moisture can get in there, and will corrode it. That it has been like that for 30 years and not caused a problem, doesn't mean it will continue to do so. It really costs very little (in terms of time or materials) to fix all that up, and could well save you an afternoon spent at the side of the road or a ticket from law enforcement... Others will disagree and that's fine. It's your wiring and your decision. I have no emotional investment in your wiring.

[Bigfoot Mike]

Ok question.... What's a new axle with brakes cost?

When I bought my high lift axle, it was $350.00 USD plus shipping. I was able to negotiate that to $250.00 USD plus shipping.

Shipping was $100.00

I traded the take off axle (it was new) for labor to install the high lift axle.

BTW: I complete set of new hubs, brake drums and brakes is $125.00 USD.

[Dave Mac]

A new axle with brakes is going to cost a bunch of money that you may not need to spend... The brakes are really simple in theory...
(Snip)
Once you confirm basic function, I would simply run new wire to the trailer connector... The higher the gauge, the better, in my opinion but I think 12ga is probably a reasonable thickness... There's not much current flowing through the brake wires so loss is not that much of an issue.
(snip)
btw, my highly sarcastic post earlier in the thread was intended as levity towards Brian which apparently was taken correctly by Brian but others took offense for some reason...

I'm with you on the simple brake thing. I have a feeling (if the weather would cool off) I will be pulling off the drums and seeing whats in there. New wiring seems pretty easy and from what I see and you see in my picutres new wire is necessity. I would like to find a nice wiring block as seen in Greg's post and start from there would seem to be the right direction. Get the block set and fuses setup and then bring new wire to it. Some nice sheathing for the wire and maybe zip ties? Zip ties may not last long enough though I'll give that some thought..

This morning the wife and I went in and stripped the old carpet off the ceiling and putty knifed off what glue or whatever was up there. What a mess. I need to find some wood for my new "Wood Group" or at least the hatch covers. The heat is preventing me from getting very far.
Dave

[Roger H]

I'm with you on the simple brake thing. I have a feeling (if the weather would cool off) I will be pulling off the drums and seeing whats in there. New wiring seems pretty easy and from what I see and you see in my picutres new wire is necessity. I would like to find a nice wiring block as seen in Greg's post and start from there would seem to be the right direction. Get the block set and fuses setup and then bring new wire to it. Some nice sheathing for the wire and maybe zip ties? Zip ties may not last long enough though I'll give that some thought..

This morning the wife and I went in and stripped the old carpet off the ceiling and putty knifed off what glue or whatever was up there. What a mess. I need to find some wood for my new "Wood Group" or at least the hatch covers. The heat is preventing me from getting very far.
Dave

Dave... a couple of points. First, the wiring you see goes to the brake magnet. It won't have any splices between the connector you see and the electro magnets. If you feel you need to replace the wiring, I'd suggest you replace the magnets rather than trying to splice inside the drum. Splices inside the brake drum aren't a particularly good idea. Generally, the brake wires are sheathed with a pretty tough nylon mesh covering over the actual brake wires (which appears to be what yours are currently), and they generally exit the drum through a rubber grommet through the hole in the backing plate. New magnets may not have the nylon sheath over the wires, and aren't shipped that way.

Second, never leave power on to brake magnets for more than a couple of minutes. They will overheat and burn out very quickly, especially drawing a full amperage load directly from a battery.

Roger

[Herb P]

I'm with you on the simple brake thing. I have a feeling (if the weather would cool off) I will be pulling off the drums and seeing whats in there. New wiring seems pretty easy and from what I see and you see in my picutres new wire is necessity. I would like to find a nice wiring block as seen in Greg's post and start from there would seem to be the right direction. Get the block set and fuses setup and then bring new wire to it. Some nice sheathing for the wire and maybe zip ties? Zip ties may not last long enough though I'll give that some thought..

This morning the wife and I went in and stripped the old carpet off the ceiling and putty knifed off what glue or whatever was up there. What a mess. I need to find some wood for my new "Wood Group" or at least the hatch covers. The heat is preventing me from getting very far.
Dave

A terminal block like that is one way to do it and it's a good plan... I use breaker panels myself but it's largely personal preference...

There are a few ways to deal with sheathing... The common approach is to get the black ribbed stuff and there's not much wrong with it other than it gets brittle over time... I have a spool of this stuff that is a braided nylon that expands when you push it (like a chinese finger puzzle)... I've had the spool for years and I use it for all the harnesses I build for various vehicle projects... It seems to hold up ok but is relatively expensive... There's also some translucent white spirally stuff that works fairly well to stave off abrasion but is really tedious to install for long runs and doesn't really seem to protect the wire from the elements... But again, I'm not a professional so I just use what I have... I really really despise electrical tape. After about 6 months, it goes all gooey so if you ever want to do a repair, you get sticky from head to toe... If you're at an electrical supply store, then ask for some self-fusing tape. It's not sticky and the way it's applied is you pull it off the roll, stretch it, and wrap it around whatever... It then fuses to itself and turns effectively solid rubber... The only thing it doesn't like is heat, solvents and engine oil so it doesn't work so well in the engine compartment of your car but is ideally suited to under or in your trailer. Heat shrink is also good if you are going to solder wires together. If you have the patience, I recommend connecting to your brake wires using solder and then heat shrink ( the kind with integral glue is awesome)... Failing that, butt splice connectors work; I have ones with built-in self-gluing heat-shrink so after I crimp the splice on, I wave a heat gun at it and it shrinks over the wire insulation and the glue seals it absolutely waterproof...

As far as zip ties, they're good to use for securing things, but for outside use, get some high quality black ones which don't turn brittle in the presence of UV... My pet peeve is when people cut zip ties with a knife or side cutters. There's always a small (1mm or 2mm) sticking out the end so when you reach down into your dash, or engine compartment or storage compartment, the ends of the zip ties gouge into the back of your hand or underarm. The right way to use them is to buy the little $10 stretcher gizmo that stretches the zip ties, cuts them and then releases them so they're flush.. The other way is to get some flush side cutters and give the zip tie a little tug at the same time as you snip the end off. Then the end sort of snaps back into place leaving a nice smooth surface; but it takes a bit of practice to get that right...

Once you've made a small investment in all this stuff, you'll be able to make long lasting high quality repairs and harnesses and will have trouble free camping for many years...

[Dave Mac]

Dave... a couple of points. First, the wiring you see goes to the brake magnet. It won't have any splices between the connector you see and the electro magnets.
(Snip)
Roger

I was not looking to replace any wire already in the drum. I'm with ya though. I am looking to put new connectors on the existing wire coming out of the drum (no connectors there now) and going from there. I want to open the drum to see what it all looks loke and clean up or replace what is needed.
Thanks much Roger

[Dave Mac]

A terminal block like that is one way to do it and it's a good plan... I use breaker panels myself but it's largely personal preference...

There are a few ways to deal with sheathing... (Snip)

Wow... Thanks for all the info. I get a great idea with each post here! I'm gona find me some of that sheathing you mentioned. And I have some of the black zip ties I got at work from the HVAC installers. They may be a bit large but because of them being thicker I guess they'll last that much longer. I assume zip tieing around the sheathed wire to the axle will be a must and someone gave the suggestion of leaving a nice loop for the axle to articulate with out pulling on my wires. Also I have a solder gun so I like this idea also rather than using a connector. And Getting this wiring together with zero connectors would be nice.
Question on the wiring from the individual wheels should I be bringing each wheels wires to the distribution block or bring the right wheel wires to the left wheel wires and connect the two then go to the distribution block? I don't have much to go on from what's left of the wiring thats there now.
Dave

[Roger H]

Ok question.... What's a new axle with brakes cost?

Dave,

A good rubber torsion axle has a design life of about 20 years and some of them make it to 30. Your '79 should have lots of years left it in at this point unless it was underspec'd (as was my '87 Burro) to begin with and wore out prematurely. You can price them directly but when I put a new Dexter #10 3,500 lb axle with 10" electric brakes under my Burro 17' two (three now?) years ago, that axle was roughly (IIRC) $350 fob Cedar Rapids, IA. It cost me about $250 to have a welder cut the old axle off and install the new one.

A #9 axle rubbered at 2,200 lbs would be substantially less than the #10.

Hopefully that'll give you an idea of what you're looking at.

Roger

[Herb P]

Question on the wiring from the individual wheels should I be bringing each wheels wires to the distribution block or bring the right wheel wires to the left wheel wires and connect the two then go to the distribution block? I don't have much to go on from what's left of the wiring thats there now.

I would probably tie the left/right wheels together at/near the axle and then just bring 2 wires forward... I don't really think there's any advantage to running 2 pairs of wire to the front, where you're just going to have to join them together anyway...

For this project, it's not clear that a terminal block or breaker panel is going to buy you anything except possibly debuggability... On my current trailer, I didn't touch the 'tow' wiring... So it comes in from the tongue, and then runs around through the trailer to the various lights and then out the floor to the axle... It all seemed relatively sane so I just organized it a bit and left it. All the cabin wiring was ripped apart and unspliced and run through a breaker panel, to a main breaker and from there through a fusible link to the battery...





In this picture, the power comes in through a fusible link, to the main breaker (top left). From there it splits off to the inverter. There's also a feed on that side from the automatic battery charger. (not pictured). On the other side of the main breaker is the feed from the solar charge controller, and then it goes off to the panel (far right). There's a big copper ground strip far right, forward of the panel where all the grounds are attached. The AC breaker panel is the brown 'hunk' on the bottom left of the picture. It's the old AC panel hacked off of the original Boler power converter... It feeds the fridge, battery charger, and convenience outlets.

All the multi-colored wires lying underneath the red/black/white are the tow wires (ground, tail, left, right, brake). The whole setup is not 100% clean and organized, but it's organized enough, well labelled, and should be easier to debug out in the field.





There's the DC breaker panel.

[Brian B-P]

Nice job, Greg! I like the terminal block.

Another terminal block option is one of the wiring boxes sold for wiring commercial trailers. It's a seven-terminal strip in a plastic box with a gasketed cover, intended to be installed outside (although you could use it inside). I used one for my Boler.

The terminals of the commercial wiring box are labeled, although some substitution is required: the commercial 7-way wiring does not include brakes, but does include a separate brake light terminal, and does not include battery charge but does include clearance lights - the studs in the strip are all the same, so I just used put the wires on (using crimp-on ring terminals) in sensible order.

I mounted my box outside, so the brake wiring doesn't go inside the trailer body just to go out again, and all seven circuits of the connection to the tug are readily accessible for checking and testing when a light stops working (notice: when, not if...)

I would have left the original tow wiring (like Herb), but the tug end of the cable needed replacement so I was re-doing connections anyway. I cut it off at the new box location on the tongue, continued from there with new cable, and changed the wiring inside only to remove the old brake wiring.

You can just continue the random-connections-in-space of the original installation. It is the industry standard practice, and the only thing which looks particularly bad in the existing situation is the wires which are connected to nothing (but you'll fix those). I would want to check those wire nuts, though: crimp-on connections are fine, set-screw wire nuts would be okay with me, but just twist-on stuff scares me in a vibrating environment. My stove hood fan had them, and they fell off when I touched them (to fix the non-running fan).

[Brian B-P]

To test the brakes, I did what Herb did. For the one which didn't work, I checked its resistance with a ohmmeter - a typical brake magnet has about 3.8 ohms of resistance... anything vaguely close to that suggests magnet which is neither shorted out nor open circuited (broken wire).

To test the mechanical operation of the brakes with no wiring in place yet (other than the pigtails of the magnet), I would certainly just apply 12 volts. That's what the breakaway switch does. As Roger says, I suppose you don't want to do this for a long time. Also, the brakes are applied by the arm which the magnet rides on only due to rotation of the brake drum - to really know they work, you need to have the drum in place and spin them.

Dexter publishes an Operation Maintenance Service Manual, which is available from their website (and would be a nice addition to the Document Center...). Even if the axle is Dexter, it's a clear and useful guide.

[Herb P]

To test the mechanical operation of the brakes with no wiring in place yet (other than the pigtails of the magnet), I would certainly just apply 12 volts. That's what the breakaway switch does. As Roger says, I suppose you don't want to do this for a long time. Also, the brakes are applied by the arm which the magnet rides on only due to rotation of the brake drum - to really know they work, you need to have the drum in place and spin them.

Sorry to hijack the thread but I've been meaning to ask about the breakaway switch. I've presently got it "ignored" but do need to address it. It looks like it got used at some point because the cable is broken at one end (torn)... So, is the breakaway switch a single-use item to be replaced after a "significant event" or can one have multiple "significant events" with it?

[Brian B-P]

...Question on the wiring from the individual wheels should I be bringing each wheels wires to the distribution block or bring the right wheel wires to the left wheel wires and connect the two then go to the distribution block?

On one hand, I agree with Herb that they need to come together anyway, and I copied the original (I had something to copy...) by bringing them together in the middle of the trailer (underneath) and running a single 2-conductor cable forward. I did this as much because the clips were there to hold a single cable as for any electrical reason.

One advantage of running each brake wire separately to the a single junction point is that it means one less connection. Almost every electrical wiring problem I've seen (in the Boler, cars, house, appliances, computers...) is at the connections; wires themselves rarely fail.

There was, perhaps, more distance from brakes to wiring terminal in my 17' Boler with the terminal block out on the tongue than the 13' Burro would have. I don't know if this matters.

[Pete Dumbleton]

Breakaway switch is a multiple use gizmo, usually a non-conducting pin between two sprung contacts. Tekonsha warns on Prodigy to NOT pull pin when TV is hooked to Egg or damage may result to controller.

I agree with the cable tie cutter; they were a must-use in the telephone company to prevent injury. In my experience, black ties are UV proofed, but white ties usually aren't unless the package is marked; telco always uses black outside.

[Brian B-P]

Sorry to hijack the thread but I've been meaning to ask about the breakaway switch. ... It looks like it got used at some point because the cable is broken at one end (torn)... So, is the breakaway switch a single-use item to be replaced after a "significant event" or can one have multiple "significant events" with it?

This can't be a single-use item, because it's operation is supposed to be tested. When I tried to test mine, I couldn't pull the plug out (the plug being the part which is connected to the cable; when the plug comes out the switch closes) so I detemined that I needed a new switch. I can pull the new one out (it takes a significant tug, but you wouldn't want this falling out...), and have done so a few times in testing.

The crimping of the loops on the ends of the cable sounds like more of a concern to me than the switch itself. I've noticed with our dog's tie-out cable (same thing, bigger scale) that the ends pull apart more easily with time as the plastic covering degrades and the perhaps the wire corrodes.

With a breakaway switch, you don't need a brake controller to test the brakes when stationary. In fact, a good (proportional) controller is lousy for stationary testing, because you need an assistant to hold the manual control lever on while you work on the trailer. Good help is hard to find these days, so I don't have any...

I don't think the breakaway switch is sensitive to the "significance" of the event. As long as the plug pulls out without mechanical damage, and clicks back in properly, I don't see a need for replacement; of course, it's a cheap item so if you have a real problem its cost will be irrelevant, but I wouldn't have a problem with just not knowing its history.

The full braking current is only about 6 amps per axle, and it's hard for me to imagine a breakaway switch not being able to handle that indefinitely. The same switches are used for up to four axles, so I figure ours have it easy.

[Brian B-P]

btw, my highly sarcastic post earlier in the thread was intended as levity towards Brian which apparently was taken correctly by Brian but others took offense for some reason... My point (and Brians probably) stands.. Any wiring outside the trailer needs to be secured, sheathed, and sealed...

Absolutely... on both subjects!

[Herb P]

I agree with the cable tie cutter; they were a must-use in the telephone company to prevent injury. In my experience, black ties are UV proofed, but white ties usually aren't unless the package is marked; telco always uses black outside.

I only mentioned it because I made the mistake of buying a cheap bag of black zip ties from princess auto... When you cinch them by hand, the little square housing stretches ever so slightly causing the little lock tab to come loose as soon as you let go of the tail end... They work ok if you use the tool to tighten them but after about a month of sitting exposed to the sun, these black ones became brittle and simply shattered...

So, I guess you get what you pay for. Don't assume they're good against UV just because they're black. The electrical supplier I buy stuff from here in town carries Panduit and they're a high quality item. I'm somewhat less fond of the Mode ones that some of the other places carry but they also seem to work just fine.

[Dave Mac]

Ok I got a brake drum off this morning and here are my pictures.

[Roger H]

Ok I got a brake drum off this morning and here are my pictures.

So, Dave... what's your assessment?

Roger

[Dave Mac]

So, Dave... what's your assessment?

Roger

I would say the drum is fine.
The bearing looks good but needs to be greased/packed.
The shoes are fine and all the mechanics look ...almost new.
Having never seen one I am wondering about the magnet it's self. I don't know how much meat these things start out with. I see where it has been worn down but is this typical standard where and is this magnet ok or should it be replaced?

Also more pictures here I am wondering about the way the magnet fits on the post I see it attached to. Is there supposed to be that much slop between the magnet casting and the post it is over? Last picture is after hosing off the brake parts.
Also the wires look fine. I dont feel any rubber grommet on the back but the wires are undamaged. I pulled them into the brake area and checked them.
How am I doing?