Kraton Issue with Hot Racing Steering Bellcrank / Servo Saver (AON4801)

[nyev]

Hi,

Just thought I'd post an issue I encountered installing the Hot Racing AON4801 Steering Bellcrank / Servo Saver for my Kraton EXB build.

When testing the steering on the bench with the Hotracing Bellcranks installed, I noticed the steering was binding, slightly, at the extreme ends of the steering travel. On inspection I found that the Hot Racing bellcranks were slightly grazing against my Hot Racing front gearbox. To avoid this issue entirely by setting endpoints, I found I needed to set each side's endpoints to 65/100. So, a lot of steering travel sacrificed.

I then inspected the stock bellcranks, and found that Arrma has carved out a tiny notch exactly where the Hot Racing bellcranks were scraping. The stock Arrma parts almost look defective due to these notches which look like chips, however they need to be there to avoid binding. I considered dremelling out the hot racing bellcranks at that location, but concluded that it would be too dicey considering the proximity to the nut.

Long story short I went back to the stock bellcranks and the problem went away. I suppose that's the risk with aftermarket parts. But on the other hand the Hot Racing gearboxes completely resolved the issue I was having with varying mesh on the diff input/ring gears, where the mesh was very inconsistent when turning the input gear by hand. With the Hot Racing gearboxes the mesh was totally consistent through rotation.

Here are photos comparing the Hot Racing bellcrank with the stock bellcrank. Note the notch Arrma has removed out of the stock plastic bellcrank, and the small scratch where the Hot Racing bellcrank was rubbing up against the gearbox:

 

[slick2500]

I wonder how Hot Racing missed that? Does that nut come out? It might make it easier to grind it down a bit.

 

[nyev]

I wonder how Hot Racing missed that? Does that nut come out? It might make it easier to grind it down a bit.

To me it looks like the notch removed from the Arrma stock part may have been a revision? It just looks like it was an afterthought - it seems odd if Arrma had designed it that way to start. But who knows.

I didn't really try to remove the nut from the Hot Racing part, but really I would still be worried that I would either take off too much or not enough with the dremmel. Too much material removed and the nut may not have enough support, or the part may lose strength when taking side impacts to wheels...

One of those cases where stock was just easier...

 

[#ARRMArcfanboy4life]

To me it looks like the notch removed from the Arrma stock part may have been a revision? It just looks like it was an afterthought - it seems odd if Arrma had designed it that way to start. But who knows.

I didn't really try to remove the nut from the Hot Racing part, but really I would still be worried that I would either take off too much or not enough with the dremmel. Too much material removed and the nut may not have enough support, or the part may lose strength when taking side impacts to wheels...

One of those cases where stock was just easier...

I don't think my talion has that, but I do not know for sure.

 

[nyev]

If you order the spare bellcrank that is stock with the Kraton EXB, the spare also comes with the notch in it. Not sure if the Talion has the same bellcrank part number but it wouldn't be difficult to compare the exploded diagrams for each truck. My guess is it's likely the Talion and Outcast use the same part number. But again, if yours is older, it's possible Arrma made a revision to this part to solve the binding issue, which would explain how Hot Racing "missed" this in their design.

 

[Sargent_Horse]

Try shimming the bell crank assembly up is there is any up and down play.

 

[nyev]

Try shimming the bell crank assembly up is there is any up and down play.

Yeah I just found another thread on binding steering where this was the same issue, and the solution was to shim the bottom of the bellcrank. That probably would have worked. But I’ve reinstalled the stock bellcrank and couldn’t really be bothered now! I checked and there doesn’t appear to be up and down play on the stock part now. And if there was it wouldn’t graze the gearbox due to the notch Arrma cut from the part....

Seems like the notch Arrma put in the bellcrank is a sure fire solution, albeit seemingly a bit of a hack fix...

 

[YoEddy]

Yeah I just found another thread on binding steering where this was the same issue, and the solution was to shim the bottom of the bellcrank.

Could you please post the link to the mentioned article because I would be very interested in it, thank you!

Greetings