klutchdust
Orange, California
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Grit dog wrote:There's more to what you just posted.
Truck brakes don't "not work" and then work again.
How much experience do you have towing and how well do the trailer brakes work?
Neighbors truck had similar symptoms, not towing though. Had to push the pedal real hard sometimes. The master cylinder was going bad. replaced that and the booster and all is good.
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klutchdust
Orange, California
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Tyler0215 wrote:Get the truck brakes checked NOW! The next time they fail you might be coming up to a red light at a busy intersection.
Asking for brake repair on a discussion forum won't stop the truck.
That's what emergency brakes are for.
In a panic stop (Wrong way driver coming at me on 14 in Mojave ) I pushed the pedal to the floor, trailer brakes locked and the rig kept moving. The anti lock brakes are part of the equation also. Truck brakes are not going to lock and it gives you the impression that the truck is not stopping but it is. It traveled the same distance, my guess, as if the wheels were locked and you were skidding. My brake pedal was hitting the floor. My brakes didn't fail. The trailer brakes did their job.
Not sure what the OP experienced. Not enough information.
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KD4UPL
Swoope, VA
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I don't of any possible way trailer brakes can disable truck brakes.
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JRscooby
Indepmo
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Lwiddis wrote:And low fluid means a leak most of the time.
Not always. As the pads wear more of the fluid stays in the cylinder of calipers. This can show as low fluid.
KD4UPL wrote:I don't of any possible way trailer brakes can disable truck brakes.
Non-functioning trailer brakes cause a severe overload of TV brakes. Overheated brakes have less stopping power.
I have heard hot fluid can make pedal feel strange.
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LarryDel
Lewes, Delaware
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I had my truck brakes checked. They are fine. Also brake fluid is full, no leaks. I have been towing travel trailers for more than 10 years. Up and down mountains 10,000 ft, 8% grade. Never had a problem. Worked just fine previous 4 days in the mountains of Western Maryland. This happened on a flat surface while driving through Delaware which is flat as a pancake. Could the 7 pin connection be the problem? Mystery continues.
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Krusty
Calgary, Alberta,Canada
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Did you try applying the trailer brakes manually with the brake controller? What happened? Did you try increasing the gain?
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LarryDel
Lewes, Delaware
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I did not try the applying the brakes manually with the brake controller. No need to as we were only going 45 miles per hour on a flat surface and the truck breaks were enough to bring us to a safe stop, although I had to put my foot all the way to the floor. I did not try increasing the gain as it was set at 2.0 which is more than enough to work. Again, what caused my truck brakes to fail? My truck brakes work fine as soon as I disconnect the trailer. Never had this problem before in 10 years of towing.
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opnspaces
San Diego Ca
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Definitely getting the truck brakes checked out was a good start. Now that you know they are good it's time to focus on the trailer.
Maybe the truck brakes never failed. The problem is the trailer brakes failed and the weight of the trailer was too much for the truck to stop alone.
Could you have driven over something in the road that broke the brake wire under the trailer? I would carefully inspect the umbilical cord for any damage. Then crawl under the trailer and follow the brake wires seeing if anything is cut or broken.
Yes the problem could very well be in your 7 pin. Have you recently had issues where the trailer lights sometimes don't work until you unplug and replug the connection multiple times?
Maybe hook the trailer back up and pull it at about 10 mph and slide the manual lever over full. Do the trailer brakes seem to engage?
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valhalla360
No paticular place.
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LarryDel wrote:I did not try increasing the gain as it was set at 2.0 which is more than enough to work. Again, what caused my truck brakes to fail? My truck brakes work fine as soon as I disconnect the trailer. Never had this problem before in 10 years of towing.
2.0...out of 10.0? It may be that they work but barely. How strong is the pull if you just activate the trailer brakes manually?
Add in a loose or corroded connection and you could see a sudden reduction in braking from the trailer brakes. Now the truck brakes are asked to cover both truck & trailer and truck brakes may overheat.
Of course, this is just a guess as it's not clear from your description and there is no direct interaction between the trailer brake controller and the truck brakes.
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Grit dog
Black Diamond, WA
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LarryDel wrote:I did not try the applying the brakes manually with the brake controller. No need to as we were only going 45 miles per hour on a flat surface and the truck breaks were enough to bring us to a safe stop, although I had to put my foot all the way to the floor. I did not try increasing the gain as it was set at 2.0 which is more than enough to work. Again, what caused my truck brakes to fail? My truck brakes work fine as soon as I disconnect the trailer. Never had this problem before in 10 years of towing.
This is one of the most contradictory statements I've read in a while.
Although it appears that whatever happened on that flat road in Delaware could forever remain a mystery.
I cannot begin to even surmise, after 30 + years of driving more, towing more and working on more vehicles than most people, how that particular sequence of events would happen and then correct itself immediately.
Although you may be saying that the truck brakes still "don't work" when the trailer is plugged in....
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