Forum Discussion

Cecilt's avatar
Cecilt
Explorer
Apr 24, 2017

Should TT Brakes Lock Up

Have a 36' 9500 loaded TT and a new 2017 F 350, CC, SWR truck.

Just had the bearings repacked and brakes adjusted before start of season by local shop. When I picked it up I did not feel much from the TT brakes.

I took it back and me and the tech turned the star wheel on the back of the drums until we felt some good friction than backed it off. The wheel would turn pretty freely and there was a slight amount of the noise from brakes hitting the drum. Did this on all 4 tires.

Set the gain to 10, got up to 20 mph and applied full pressure to brake controller(integrated) and could feel the TT brakes but no where close to locking them up. After pulling about 200 miles it actually felt like more resistance on the TT brakes when pulling into the CG using the same test. Is this normal? Couldn't lock them up but felt that they gave a bigger jerk to the truck when fully applying the controller.

My question is should a gain of 10 lock up a TT this heavy. I kept in on 10 for a 1700 mile round trip. No issues but then again I have an exhaust brake and pulled from VA to FLA so it was flat land. I just want to make sure I am getting stopping assistance from the TT as well as the truck in an emergency braking situation. tks
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Apr 24, 2017
    When using truck brakes and therefore trailer brakes get applied you are NOT sending FULL battery voltage to trailer brakes ----proportional braking based on how hard truck brakes are applied


    IF you are going 20 mph and apply trailer brakes via MANUAL Lever FULL battery voltage WILL be applied to trailer brakes and you MAY or may not full lock up trailer brakes.
    S/B able on dirt/gravel....maybe on asphalt---maybe BUT should notice strong braking action

    Setting on 10 is too high in my opinion----brakes are still too loose.
    Spin wheel and it should rotate 3/4 turn then stop when brakes are adjusted.
  • Cecilt's avatar
    Cecilt
    Explorer
    Apr 24, 2017
    Old-Biscuit wrote:

    Setting on 10 is too high in my opinion----brakes are still too loose.
    Spin wheel and it should rotate 3/4 turn then stop when brakes are adjusted.


    Agreed. I set to 10 in hopes of dialing it back to 7 or so to keep them from locking up. I you-tubed adjusting brakes and one video said to turn the star wheel until you can't manually turn the wheel by hand and then back off the star wheel about 8 times. Does this sound right. I assume you are also suggesting that once brakes are adjusted properly they should only rotate 3/4 turn without applying brakes while tire/wheel are still in the air. I know for a fact we could turn ours and it would spin a few rotations or more. tks
  • dodge_guy's avatar
    dodge_guy
    Explorer II
    Apr 24, 2017
    When the system is 100% functional and in good repair you should be able to lock them up which is 100% braking force.
    On my current trailer I spent almost 2 years figuring out why I wasn't getting full braking from the trailer brakes. After cleaning adjusting, checking connections, voltage and amp draw as well as resistance checks everything was showing OK. As a last resort I changed out all my brake magnets and after 20 miles of burnishing them in the trailer finally was able to lock up the brakes manually. Obviously you don't set them so they lock up, but you want to be sure you are getting full brake application. I would say I was originally getting about 40%!!! And when I found this my trailer was 2 years old with about 1500 miles on it. It would stop but not as well as my previous smaller trailer. After I fixed it the heavier trailer stopped faster than my lighter one did. And it still brakes very well to this day.
  • time2roll's avatar
    time2roll
    Nomad
    Apr 24, 2017
    Often the brakes need to run in a bit when first adjusted or have been in storage for a bit. This would drive me crazy with electric drum brakes. Put the gain up for a while then need to back off some. Yes should lock up when properly adjusted etc. but not all do. This all pushed me to go disk with all issues eliminated.
  • MFL's avatar
    MFL
    Nomad II
    Apr 24, 2017
    My Ford owners manual says set IBC to 6.0 to start. This would lock my brakes instantly, when using the manual control at 20mph. Even at 5.5, too much, would slide tires on concrete. I keep mine at 5.0, just right for my FW with 12" brakes. I can stop truck and FW, at lower speeds, using manual control only, with setting at 5.0.

    I would suspect your trailer wiring may be light, or not making good connection at some point, or maybe just smaller brakes and hubs. I have my brakes adjusted to just make one revolution, with a light spin of wheel. It is about 4 clicks out, from not being able to turn wheel by hand.

    Jerry
  • ScottG's avatar
    ScottG
    Nomad
    Apr 24, 2017
    Even though my brakes are large for the weight of the TT, I have never been able to lock them up - even with different brake controllers. Many on here report the same thing so I wouldn't get too concerned about that part.
  • Turtle_n_Peeps's avatar
    Turtle_n_Peeps
    Explorer
    Apr 25, 2017
    A lot of brake systems on new trailers are garbage. Total garbage.

    I have An old TT and when they are adjusted up properly I can smoke the tires on pavement at speed. I also have two car trailers that have old axels on them and I can smoke the tires on them at full load. All of these trailers have big brakes and big mags on them.

    A lot of the new stuff is just garbage. I've glad I have old brake systems on my trailers. A lot of the wiring is also junk in these new TT.
  • TBammer's avatar
    TBammer
    Explorer
    Apr 25, 2017
    Drum brakes have a break in period. I remember this from my old days working at the local gas station. My research on trailer drums lead to an adjustment of pulling the loaded trailer at 25mph on concrete or asphalt, and then hit the manual slider and seeing if the trailer brakes lock. Adjust the max power until just shy of locking up. For my trailer that is 6.0 out of 10. I do that every time heading out. If I had to set the controller to 10 and it would not lock up, I'd say its time for new magnets, which means probably time for new shoes, which means just buying the package backing plate already loaded for installation.
  • Thomas_NH's avatar
    Thomas_NH
    Explorer
    Apr 25, 2017
    Did you say you have a new Ford? Then you need to hook the trailer up to it and scroll down through the truck settings, find the trailer breaking part. Re-set to the heavy trailer setting.

    I was under-impressed with the breaking on mine (2016 F250). While sitting in a parking lot on our last trip, waiting for the DW shopping I found the setting. I move it to heaviest trailer setting and left the gain at 10. Once back on the road we came to the first light (25-30 mph) I stepped on the brakes with the usual force... Thank gaud for seatbelts or I would have done a faceplant into windshield. The smoke from the wheels rolled down past us while we waited for the light. The wife asked, "What the hell happen"? "Did someone just hit us?" I said,"No, I think the brake adjustment must have got move, I'll readjust it."

    I never could find this adjustment on the dash when the there was no trailer connected. It all makes since now, it's adjusted differently for each trailer you have logged into the truck's computer. To bad they didn't say this in the owner's manual. The gain is now at 7.

    BTW: On the light trailer setting, sliding the brake control lever over never would lock them up. It sure does now!

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