Brake Size

Discussion in 'Tires / Brakes / Bearings / Axles' started by MikeS2, Sep 20, 2011.

  1. MikeS2

    MikeS2 New Member

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    I have recently purchased a 2003 Rockwood 2270 that has 7" electric brakes with a 3500lb axle. The brakes do not seem to be effective at all even after adjusting them (they were totally out of adjustment) and cranking up my controller to max setting (Prodigy P2) the rig still moves from a dead stop at idle to about 5 mph - w/o trailer brake goes to about 10 mph. Considering the age of the brakes I am going to replace the assemblies but shouldn't this PUP have 10" brakes on it? I have also upgraded tires/rims to 13" so there is plenty of wheel clearance for 10" drums.

    Anybody have this axle/brake size combination?
     
  2. md-500man

    md-500man Member

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    MikeS2
    WE have an 03 Flagstaff 228 with the 7 inch brakes, and I also did not get what I thought should be the proper amount of braking power out of them when I first used them. I tore them apart and cleaned and adjusted everything and then found one of the magnets to be defective. I just replaced both of the magnets and that made a world of difference, BUT keep in mind these are 7 inch brakes. I adjusted mine several times and finally have them were I think they are as good as 7 inch brakes are going to get. In other words you can certainlly feel them apply and work berhind our ford escape, but behind our f-350 and behind our boat I know they are working but its just not as obvious.
    As far as a 3500 lb axle with 7 inch brakes I may be out of line here but I thought the drums and bearing's on a 7 inch system were designed for the 1500 to 2000 lb axle. and the 10 Inch brakes for the 3500 lb. axle. I know that on my axle If I want to upgrade to the 10 inch brakes I had to replace my axle to the 3500 because of the difference's in the bearings on the 10 inch drum vs. the 7 inch drum. I hope this helps ya
    Well its off to the old salt mine for 8 hours Good luck MD
     
  3. rabird

    rabird Howdy!

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  4. MikeS2

    MikeS2 New Member

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    Ok, I got up underneath the PUP and saw that there is a metal tag on the axle. It is an Al-ko T20-2 axle that I looked up and it is a 2100lb axle, set-up with 7 X 1 1/4 electric brakes, 2 leaf springs rated a 1080lbs each. I guess I don't understand how a trailer that has a dry weight of 1892, payload capacity of 966, GVWR - 3024, Hitch weight - 274, and axle weight of 1618, and 7" brakes rated for 2200lbs per pair just don't add up. And I went to a 13" tire because I couldn't find a replacement 12" locally that was rated more than 1045lbs per tire. I guess my tires are not my weakest link, seems like the axle/brake combo is right at or below the limits? Looks like I better pack light....
     
  5. screwballl

    screwballl Stimulus Package

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    The brakes are there to help, not to bear the entire weight (or even most) for stopping power. The TV is what should be bearing the majority of braking power with a little help from the trailer, mostly to help keep it from getting out of control on emergency stops/swerving. My pup is around 2500 GVWR, has no trailer brakes at all and never had a problem here, but I also tow with a (almost) full size that is rated up to 8700 lbs towing.

    It is only when you get up to the larger 3500lb+ trailers where the brakes actually start grabbing much more due to the increased weight.
     
  6. fix_it

    fix_it Member

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    You say the trailer came with 12" wheels? That is one reason that it has 7" brakes. The other is that the 10" brakes won't fit on a 2000 lb axle. The backing plate will, and the outer bearing will, but the inner bearing and seal won't. Timkin makes a bearing and race combo that looks like it might adapt the 10" drum to the 2000 lb spindle. The bearing number is JLM67042 and the race number is LM67010. I found these through the Timkin catalog. However, I could not readily find a seal that would match up. A machine shop theoretically could turn an adapter bushing on a lathe that could allow the use of the standard 2000 lb bearing and seal in the 3500 lb hub. I'm not sure if you could find a shop to do the work, though.

    I feel you on the lack of effectiveness of the 7" brakes. I have 10" brakes on my Jayco, which is a little on the heavy side. I wish they did a little more. Mine won't come close. I would hate to have 7" drums on it. Good luck in finding a solution.
     

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