Center diff bearing fit in Hot racing motor mount

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msmy300z

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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?
 

joostin420

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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: https://www.arrmaforum.com/threads/anyone-running-tp-4070cm-2200kv-on-6s.5381/page-2
 
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bicketybam

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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.
 

olds97_lss

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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.
 

Lingerfelter6

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I am now facing the same issue. Tried all suggestions from greasing to heating / freezing, but with no success. Still using the stock bearings, fast eddy bearings will be in the next round of upgrades. Will the fast eddy bearings sort this out?
 

bicketybam

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I am now facing the same issue. Tried all suggestions from greasing to heating / freezing, but with no success. Still using the stock bearings, fast eddy bearings will be in the next round of upgrades. Will the fast eddy bearings sort this out?
Technically the bearings are the same size so who knows?
 

olds97_lss

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I got the same mount and the X brace on the other end for Christmas. It was a tight fit. I used a wood block with a hole so the diff cup fit on one side and tapped the other end of the diff with another block lightly with a hammer a few times. I'm not looking forward to getting the bearing back out. Guessing it's going to come out in pieces. Before I got too far, I used a wire wheel in my dremel and ran it long enough to remove the anodizing inside where the bearing seats, but it was still overly tight.

Oddly, the one on the X brace side fit better with a light tap or two.
 

bicketybam

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No one knows apparently, lol. Anyway, this is just another issue to add to the list of ever growing unresolved issues. Damn this rc life
I think that HR is a hair off with their specs. I had a rear wheel hub that I had to drill out so I could get the pin to fit. The other side fit fine.
 
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msmy300z

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Ultimately I did the same with the Dremel and sanding disk. I ground until the anodizing was gone and then some..... I still had to work to get it fully seated with grease all the way around. I had a similar positive experience with the x brace and don’t remember it being a struggle.
 

Lingerfelter6

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get some fine grit sand paper and put on your finger and spin it around till it fits... copper pipe sand cloth works the best for me to open up tolerances..
Thank you for the suggestion. It works perfectly. Sanded it down with 280 grit and finished with 600 grit. Fits just like the stock motor mount
 

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