The Stovebolt Site Forums The Parking Lot Big Bolts Wiring a trailer brake controller for '72 c50

Hello, I'm having trouble finding information on how to go about wiring up a trailer brake controller in my '72 c50. This is possible right? I have a triple axle trailer that I'm wanting to get the brakes working on it for hauling a tractor/backhoe. Any info or point in the right direction would be very helpful, thanks.

Do you have a new brake controller in hand and did it not have wiring details? are you just starting the research on how to wire one?

Electric brakes, or hydraulic surge brakes? A 3 axle trailer capable of hauling a backhoe is probably pushing the envelope for electrics unless you're planning to run brakes on more than one axle. Modern electric controllers don't require any hydraulic connections like the older ones did- - - -there's a pendulum built into the controller that energizes the electric brakes according to how quickly the tow vehicle is being braked. Just follow the printed instructions that come with the controller. The controller needs to be mounted in a position where it can be leveled- - - -they don't work well, or sometimes at all if they're not level so the pendulum can swing properly.
Jerry

Concur with Jerry. Are these triple axles "Mobile Home" axles (single wheels) or dual wheels? And what kind of load are we talking? Tractors and backhoes run a wide range of weights. We have a tri-axle trailer at work that's a pintle hitch, 25-ton capacity and it is air brakes on all three axles. Our backhoes run about 15,000 lbs and we (me!) only move them on air-brake equipped trailers. All 3 of our backhoes are Case 590 Super L's and I don't like moving them on pintle trailers. I prefer using the 18-wheeler. Speaking of tri-axle trailers ... My favorite trailer to use is a 50-ton capacity Removeable Gooseneck trailer I use to move our heavy equipment

If your trailer is a shop-built unit on mobile home axles ...

You might want to check out this thread on a different forum

Bottom line: Your brake controller should have come with wiring instructions. If it didn't, you should be able to get a model number off it and find it on line.

I put a hitch and an electric brake controller on my '65 GMC 4400. It was pretty straight forward. But it was a smallish car hauler trailer rated for 7,000 lbs. And brakes on only one axle. Braking with that kind of set up was iffy in some situations and I have since upgraded to an aluminum trailer with 5,000 lb axles and e-brakes on both axles.

Ok sorry for the lack of info on the original post lol I wasn't thinking about all that haha. My triple axle trailer has (3) 7000lbs dexter axles under it with brand new electric brakes on all 3 axles. Just installed after I restored the trailer from getting a sweet deal at an auction. It had no deck and had been sitting in a field. However the guy who built it done it right. It's also a pintle hitch trailer. 20ft deck and 5 foot dove tail with heavy ramps. Trailer weighs 5000lbs empty. So gvwr is 21,000lbs minus 5000lbs(empty weight)= 16,000lbs load capacity. The backhoe I referred too is actually my tractor that has a removable backhoe. Not 3pt hitch but a 4 point pin-on style. It's a massey ferguson 3165 tractor w/front loader and a mf220 backhoe attachment. So I think all together it will weigh in at about 8,000ish lbs or so.

But all the brake controllers I looked at have this 4 wire plug coming out of them, my suburban has one and it has the 4 wire plug that plugs into a wiring harness under my dash. My question is how do I wire the harness into my 72 c50?

Here is my truck, trailer, and tractor all together. Backhoe isn't attached. Still in process of restoring that to brand new condition too. About to get some boring done for bushings where they didn't have them before and re-boring/bushing all the existing ones as well and all new pins made. I like to make things last. Lol

I get the blue wire is for the actual brakes on trailer. White is ground. Red is for the brake switch which makes the brake lights work and in the controllers case it gets the signal brakes are being applied. And black is the power wire. Where I'm unsure is if I need anything else or can I just wire it straight up and be fine with my older truck. Alot of stuff that confuses me is with the newer vehicles requiring this or that as well for the brakes to work. And they don't say anything about older vehicles. Lucky for me my suburban had the wiring harness already wired so i just had to get a controller and plug the harness in.

Here is the basic wiring for most of all of them. you can find all the writeups on etrailer and other sites.

Most modern suv types have the harness already wired for easy installation and for their add on stuff from factory/dealer.

Mike -- Yes, you should be able to wire it as you have described. It's not complicated and there aren't any weird/obscure things about it. If the axles are modern Dexters and all three have brakes, you should have few issues with that rig. Just go easy on the controller the first test. With all three axles braking, you'll lock them up on even a light setting. So start at zero and slowly work up until you find the happy place. We don't want you getting flat spots in those tires!

Also ... try to avoid hauling an empty trailer with a loaded truck. If you have to, then be sure you adjust the brakes way down or you'll lock 'em up, make lots of smoke, create a big stink of burning rubber which will cause all the other drivers to look at you and think "What a doofus." I know a guy who did that once ...

Happy Hauling!

And as long as we're trying to save your tires ... You *did* check that 2-inch recycled concrete for little pieces of rebar, yes? Or is that big marble chunks?

What I am not the only one thank goodness. and a man who knows his rocks.

Just as a precaution, check the specs on the brake controller, some are designed for a limited number of axles.

*Excellent* point!


You have many brothers, my friend

Yeah I know what you mean on the brakes locking up. Loose gravel is the worst. But yeah I'm gonna try wring it up later this week. I have a brake controller that says it'll work with 4 axles so I should be good.

Ok here is the wiring diagram I'm gonna be following for the brake controller. One question I had was about the circuit I highlighted with yellow dots. Is that actually for the brakes or just auxiliary 12v power for say a light for a tool box or something? I'm still gonna do it but I was just curious if that was actually for the brakes?

Thanks
Mike

That wire is not required for brake control it is for other items and is part of the multi (more than 4 prong trailer plug normally) and is used for charging or any other 12 v constant needs

PIN 4 normally in the 7 plug

Depending on brakes the control box on the trailer itself my require 12 v (other than anything on blue wire) and would be supplied by the line. The trailer controller in the cab does not use that yellow wire.
Your specific unit on trailer side would specify.

Thank you for the clarification. That diagram was for trailer brakes specifically and I was wondering if that actually had anything to do with it. I didn't think so cuz I wired that circuit up on my trailers harness for a aux light in my toolbox for just incase I'm out after dark and need a chain or something. I should have this up and running in no time. Can't wait to pull my tractor again but with brakes on the trailer this time. My dump truck has decent brakes to stop it but it's probably safer to have trailer brakes so my trailer isn't pushing so hard against my trucks braking power. 3 axles of braking power and my dump trucks brakes should have me stopping really good now when loaded.

Again thanks for all the input!!!

That 12v aux feed can also be used for the trailer Break-a-Way battery charger, which you might want to install...safety first!

Mike B

With all that extra braking capacity, be sure the load is chained down VERY securely. Nothing like having a tractor sitting on your truck instead of the trailer in a panic stop!
Jerry

Good point, Jerry. I learned it this way: You'll likely never jerk the load off the back by accelerating (unless you completely goofed up securing it ...). But you could end up with it on top of you in a sudden stop. I usually make sure my loads are doubly secured at the back. In a sudden stop, I don't want 50,000 lbs of excavator joining me in the cab.

Put this image in your head you cannot go wrong. With the tie down that is.

Impressive!

The heavy duty 16 foot trailer I bought recently has hydraulic surge brakes on the front axle only, and it's obvious they haven't worked in quite a while. The sliding tongue that applies the brakes is free to move almost 3 inches back and forth, since the master cylinder is empty. I'm going to disable the sliding tongue temporarily and adapt a set of electric brakes to the rear axle until I can find the time to rebuild the surge brake system. Then either system can be used, depending on whether or not the tow vehicle has a brake controller. The trailer was originally used to haul a big skid steer loader to job sites for a plumbing contractor. I'll have that trailer at Townsend next weekend, since the other one still has a big load on it from my Indiana/Illinois odyssey. That trip included acquiring a spray-oiler 235 engine from a cabover truck, one with an updraft carburetor and a rear-dump exhaust manifold, and a 351E GMC V6, plus 4 other stovebolt engines.
Jerry.