Kraton Kraton 8s front upper A-arm - Arrma ARA330561 - major defect

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atomos319

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Arrma RC's
  1. Infraction
  2. Kraton 6s
  3. Senton 6s
Is anyone aware of a manufacturing problem with replacement front upper a-arms for the Kraton 8s? I bought some (part No. Arrma ARA330561 ) and discovered that Arrma forgot to thread the inside of the arms! (unlike the broken arm I meant to replace). Thus the pivot screw cannot be screwed in. If I got one...how many others are floating around out there? Surely I cannot be the first one to break this piece on the 8s!

I am attaching a picture below. On the left is the old broken arm, on the right is the new piece. As you can see, the inside is as smooth as a baby's bottom.

I guess I will contact Horizon. Not sure what else to do. Pretty frustrated at this point.
 

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Replacement parts are not threaded. Take the ball out and start it by hand about half way making sure to keep it straight. Then assemble normally. Have fun and good luck.
 
What he said. ^
None of the Arrma replacements are threaded and for good reason. The fastener cuts its own threads when you install it, making for a tighter fit as the first thread you make is always the tightest and strongest in polymer/plastics
 
I'm thinking the insert is too small. I just got a set of arms that are definitely not threading by hand.
 
Share a picture?
That is my experience. I could get the pivot screw to just start to turn after giving it a good hit with a hammer, but it would just pop back out and I could not get it to go deeper until I tapped some threads.
 
I would but I have already tapped them and installed. They were a few mm too small. Maybe I just got a bad set but they definitely needed some finessing
 
I broke and replaced mine and yeah was not threaded. I ended up using a small impact driver and putting some serious pressure to get it started. It was a challenge to keep it straight, but ultimately it worked out just fine.
 
Tip - get a file, and cut 1-3 notches on the first 1-2 threads on the screw. This will help them cut the threads as you screw it in that first time.

The downside to doing this, the SECOND time you try to thread it on, be careful, it will want to cut another set of new threads...
 
I just replaced my first arm on mine and I would call the replacements a perfect fit, I don't think there's an issue here gents. Yes it's tight, but that's because it's a beefy rig. The pivot ball has holes in it, just stick something through the holes so you can push and twist at the same time with some weenus grease and it cuts threads in easily.
 
There may have been a bad batch. Especially with plastic molds, not everything turns out the same.
 
I just replaced my first arm on mine and I would call the replacements a perfect fit, I don't think there's an issue here gents. Yes it's tight, but that's because it's a beefy rig. The pivot ball has holes in it, just stick something through the holes so you can push and twist at the same time with some weenus grease and it cuts threads in easily.
That's what I did. I started threading it using a screwdriver through the holes. Now I'm going to back it out and thread it the whole way with the pillow ball in the steering knuckle. Not going to lie.....took some elbow grease to get it started.

20200119_095238.jpg
 
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