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Center diff bearing fit in Hot racing motor mount

Discussion in 'Chassis & Drivetrain' started by msmy300z, Aug 12, 2018.

  1. msmy300z

    msmy300z Active Member

    Sep 6, 2017
    Likes Received:
    Arrma RC's:
    I just purchased the Channel lock secure motor mount for the 6S Arrmas and cannot get my bearing to fit the opening. It is the same diameter but just too tight of of a tolerance.

    Anyone have trouble with fitment of the diff bearing with this mount? I have tried to place my diff 2-3 times and it always gets stuck before bottoming out. I have tried both sides of the diff to see if one bearing was off but it is the same either way. I also tried greasing the hole lightly and it still got stuck with ~1\3 to go. I mean stuck! I had to put the out drive on the floor and push down on the mount until it popped out.
    The same bearing goes into the stock mount easily. I don’t see any defects on the anodizing or anything... any help would be appreciated. I don’t know if it is a defect or if I will have this problem with any of them?
  2. joostin420

    joostin420 Well-Known Member

    Sep 21, 2017
    Likes Received:
    Arrma RC's:
    Fazon, Kraton, Outcast, Senton
    Are you using the stock bearings? I replaced all the stock unsealed bearings with fast eddy sealed bearings. When I installed the hr mount I do remember the bearing fitment being a little tight.

    The more important thing is that there was play front to rear of the center diff (hr diff cup installed also). I had to use the following shims; maybe 3x shims total in the front mount/brace and 4x in the mount in the rear before installing the bearings:

    Tekno RC TKR1222 Diff Shims 13x16x.1 EB48 (10)

    Details here:
    #2 joostin420, Aug 12, 2018
    Last edited: Aug 12, 2018
  3. bicketybam

    bicketybam Premium Member!
    Premium Member ArrmaForum Fan

    Jun 26, 2018
    Likes Received:
    New Milford, CT
    Arrma RC's:
    Granite, Kraton
    I have the HR mount and it's definitely a tight fit. I also have Fast Eddy bearings. All I can say is lube it up and keep at it.
  4. olds97_lss

    olds97_lss Premium Member!
    Premium Member ArrmaForum Fan

    Dec 14, 2016
    Likes Received:
    You could also try freezing the bearing and heating the mount up. Cooling the bearing will shrink it a bit and heating the mount up will expand it. Between the two, might be easier to get the bearing in. I've had to do that in the past when replacing crank case bearings in nitros.

    Will be a real biotch to replace a bearing down the line, so make sure to put some oil on the outer race of the bearing as you put it in to hopefully help it keep from seizing.
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