Cecilt wrote:
Dropped trailer off at dealer yesterday. They said shoes and magnets were fine. Tested electrical and discovered rear axle brakes working fine but the front was not. Found a broken wire. No juice was getting to the brakes on front axle.
My question is even in this scenario shouldn't the rear axle lock up when I had the gain set to 10? It never did. Maybe the 9500 lb TT was too much for just one axle to lock up but I wanted to ask before picking it up tomorrow. tks
Hi,
Maybe this will help. I have a 2005 F350. It was the first year Ford put the integrated brake controller in the trucks. And I had one of the early ones too, the first few months of production the manual lever would not work unless the truck was going I think over 15 mph. After enough uproar, they changed the rest of the 2005 models to have the manual lever work all the time.
I also have Dexter self adjusting brakes. These are always adjusted up to ideal. The feature works well as long as the brake drums run true.
My camper is just under 10,000# when full loaded, I say this so we can compare more apples to apples trailers in stopping size.
I also did a wiring upgrade conversion. No 10 awg wire right to each brake coil, including the ground wire. See here for more info.
Independent Brake Wire Feed UpgradeOn your brakes, you need to sort out that each brake coil is getting the same current/voltage the truck is sending. The wiring methods used on some brand camper is not good. Marginal size wire drops the voltage and the current. I did not notice what year camper you have, if it is older, there is classic wire failure inside the axle tube. The wire insulation gets brittle, it is bouncing around in there and over time grinds off a bare spot. This shorts out the coil so the power it not getting to the brakes.
Next the ground. Many campers have a power wire direct from the truck to the brake coil. But the ground, they run the brake coil wire to frame ground back by the axles. Then up front of the camper, they create frame ground off the battery and join it to the truck ground. Well, those are 2 very good places to have corrosion affect the ground path to the brakes. Either end of that ground connection can mess with the brakes. It acts like the coil wire on the ground is not connected or has great resistance. Ideally the ground wire for the brakes is a wired direct from the truck 7 wire plug all the way to the brake coils. No using the frame ground for the brakes.
Connections on the brake wiring, another sore spot. If by chance they have scotch lock connectors, about all you can do with them is eliminate them. They have no good long term use in a brake circuit.
You keep trying to mechanically adjust to make this better, but if the electrical is not up to peak performance, the brakes cannot work right.
Now to the lock up, I cannot comment on your vintage controller as I'm sure yours is upgraded from mine, but I can tell you this much. I used to tow my smaller camper with this same truck, it weighed 6,000# and had 2, 3,500 lb axles. So 7,000# of brakes. If I put my controller on a gain of 10, that camper would not lock up the brakes but I can tell you they are being pumped the current. When I get out and check the trailer drums, they are hot, they are trying to hold the truck back. Too much gain as it will due those brakes in early. On this smaller camper I run a gain of 6.5
My controller creates a one to one stopping effect with the truck. I cannot force the controller to have the trailer lead the truck, even at a gain of 10. The computer throttles the brake power back to make the combo dead smooth.
It does the same on my 10,000# camper. I have the gain at 8.5 and mine has a bar graph from 0 to 100% power. I can see the controller pulsing the brakes with varying power as the truck and camper stops. It is sensing "somehow" when the trailer has enough stopping force to back off the brakes signal.
Now to the manual lever. Even with the full brake wire upgrade and the self adjusting brakes, I cannot lock up the brakes doing much anything over 30 mph. I called and asked Dexter about this, and as the other poster listed, Dexter sizes the brakes to a weight capacity and stopping distance. The magnets and the brake lining aggressiveness are sized to that weight rating stopping distance. If I have an empty camper, about 7,200#, then the brakes may lock, but not at full load at high speed.
To your question on should one axle still lock if the wires are off on the second axle, again back to the mass it is trying to stop. Normally you have 2 brake axles trying to stop the camper, if you only have 1 axle, your expecting that one axle to stop the entire camper mass when 2 are having a hard enough time. The mass will overpower the brakes and I highly doubt they will lock.
As to setting manual brakes, many folks have different way they found works for them. How I do it is, jack up the camper, adjust up until the wheel locks from hand turning. Then back off clicks until there is a slight faint rub. This faint rub is not an exact number of clicks away. I'm estimating I'm about 0.001" to 0.002" from the drum with the shoe. Do all 4 this same way and then a drag test on gravel at least when I had a brake controller that would let me. You can see if all 4 lock at the same time. If one is before the others, I back off 1 or 2 clicks and go again. When all 4 lock at once, I'm good.
Since my F350 will not do a drag test, I use brake hub temps to do this. Towing down the highway and come to a rest stop. Get out and check the drums temps with an infra red gun. The hot one, is too aggressive. You will see it, it is way higher then the rest. Back off 1 or 2 clicks and try again. When all 4 are stopping as one, the heat will be the same with a few degrees of each other.
Hope this helps
John
PS a Question: Does your 2017 controller have a bar graph or method to show how much power output the controller is doing? Look when you press the manual button, is it staying at 100% power or backing off?
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10 RA, 21,000 GCWR, 11,000 GVWR, upgraded 2 1/2" Towbeast Receiver. Hitched with a 1,700# Reese HP WD, HP Dual Cam to a 2004 Sunline Solaris T310R travel trailer.
