Kagama Team Corally ‘s new release 20 Sep is a 6s SCT

[Rotauq]

If you clearance anything it is the bellcrank arm that the bushing (part C-00180-206) rides in. By clearance, I mean lightly and uniform the inner diameter of the bell crank arm. This should only be necessary if there is a slight problem with the injection molded. That bushing (part C-00180-206) is meant to lock part C-00180-831 and the steering rack together into one solid piece and put it in double shear.

Adding even more slop to the steering is never the answer, if the servo is having problems then a stronger better servo is the proper solution.

I am running a Yipin 55kg servo that will push though anything with ease.

Skeptical as I was about the solution, the bushing was binding before and after i cleaned it. And due to the bushing length the assembly did have slob.
I intend to to replace the bushing with flanged bearings at some point, so for now it couldn't hurt to try removing the thread as nbrc proposed.
Result is a nicely free moving assembly with less slob than before as now i could actually shimm it

 

[danl]

Do you also under tighten the screws so that the bushing can now rotate on the screw threads?

 

[Rotauq]

Do you also under tighten the screws so that the bushing can now rotate on the screw threads?

Yes, the bushing can now rotate 'some' on the screw as well, but because of the added (copper) rings the screws are not under-tightened.

 

[danl]

What keeps the screws from wallowing out the holes in the soft aluminum of the steering rack and steering rack stiffener?

 

[Rotauq]

What keeps the screws from wallowing out the holes in the soft aluminum of the steering rack and steering rack stiffener?

The rings for one. And as mentioned i see it as a temporary solution until i receive the bearings i ordered.

But generally speaking I do prefer wear on a 15€ part above mediocre steering in heavy duty scenario's

 

[danl]

I don’t follow how the rings will stop the steel screw from wallowing out the soft aluminum steering rack and stiffener when loaded laterally. It sounds like it’s all working for you though, which is all that matters.

 

[Rotauq]

I can hardly follow myself most of the time so i wont blame you

Still gonna give it another try:
1. The stiffener plate is countersunk so it does not wallow out. The screw thread does not touch it at all only the head. And sure metal on metal will rub some. <Some locktite on the head might prevent the screw from turning/scraping>
2. The washers above and below the steering rack center the steel screw and are clamped down by the tightend screw+nut. Certainly prevent it from wobbling. Sure there will be moments where the screw is pushed out of it center position and wallow down the hole in the rack, but not constantly.

 

[danl]

I still don’t follow, but that’s fine. Both my corallys have smooth, slop, and bind free steering. I just had them apart and reassembled tight as a tiger with loctite. I was just curious what was being done, but since my cars are fine, it’s not worth helping me trying to understand.

 

[Atomic Skull]

I still don’t follow, but that’s fine. Both my corallys have smooth, slop, and bind free steering. I just had them apart and reassembled tight as a tiger with loctite. I was just curious what was being done, but since my cars are fine, it’s not worth helping me trying to understand.

Same, I put 0.1mm shims at the top and 0.3mm shims at the bottom on the bushing on either side of the bell crank arms to reduce lateral movement and slop and they move freely with little slop in the steering system so I'm not really understanding what the problem is.

0.2mm shims would also work, you just need 0.4mm of shim overall. 0.5mm causes binding, 0.4 is just perfect.

 

[Atomic Skull]

So I just found out that they are putting TWO 0.2mm shims under the bearing in the Shiroi hubs. Previously all Corally vehicles had only one. This eliminates any possibility of slop but it also means that some Shirois are shipping with brinneled wheel bearings because the extra shim was too much due to tolerance stacking and it overloaded the bearing. (as was the case with two of the hubs on mine)

So I guess first order of business with new TC vehicles going forward will be to pull and replace all the wheel bearings and shim them properly.

EDIT: Which hinge pin hole does the Shiroi rear hubs use the lower or the upper? I disassembled both and now I can't figure it out, and the manual doesn't make it clear.

 

[Sandracer_NL]

So I just found out that they are putting TWO 0.2mm shims under the bearing in the Shiroi hubs. Previously all Corally vehicles had only one. This eliminates any possibility of slop but it also means that some Shirois are shipping with brinneled wheel bearings because the extra shim was too much due to tolerance stacking and it overloaded the bearing. (as was the case with two of the hubs on mine)

So I guess first order of business with new TC vehicles going forward will be to pull and replace all the wheel bearings and shim them properly.

EDIT: Which hinge pin hole does the Shiroi rear hubs use the lower or the upper? I disassembled both and now I can't figure it out, and the manual doesn't make it clear.

I just checked. It’s the upper.

 

[Rotauq]

I've replaced the steering rack bushings by 2 flanged bearings (3x6x2.5) now. Works great. I can basically tighten the nut up fully without friction.
Question remains how it will deal with wet mud...

 

[Atomic Skull]

I've replaced the steering rack bushings by 2 flanged bearings (3x6x2.5) now. Works great. I can basically tighten the nut up fully without friction.
Question remains how it will deal with wet mud...

View attachment 10837View attachment 10838

Here is your solution: https://www.avidrc.com/product/1/bearings/685/3x6x25-Flanged-Rubber-MF63-2RS-bearings.html

If the bearing is loose in it's seat enough to cause slop you can set it in place with slip fit retaining compound. I find that the #648 is the most general use.

https://www.amazon.com/243-Removable-Threadlocker-Fasteners-Anaerobic/dp/B09VH9VJT6/

 

[Rotauq]

The bearing actually fit real tight. the hole is ~5.9mm, but true a little fixing agent is a good idea.

So I wanted to do the same upgrade on my spark... Then found out my ackerman plate has been scraping on the cup and even broke in 2

 

[danl]

I broke the same thing on my spark. Corally makes part COR00180-704 that is T6 treated 7075 vs 7075 without T6 for the stock part. The kagama family of cars use a beefier steering rack, but it won’t fit the spark unfortunately as they are different in a couple ways.

 

[Rotauq]

I broke the same thing on my spark. Corally makes part COR00180-704 that is T6 treated 7075 vs 7075 without T6 for the stock part. The kagama family of cars use a beefier steering rack, but it won’t fit the spark unfortunately as they are different in a couple ways.

Thx for the tip, though I already ordered the C-00180-175-3 (6061-T6)

I will be double checking the height of the ackerman to prevent the rubbing. A few shimms should do the trick i hope.

 

[Atomic Skull]

I've replaced the steering rack bushings by 2 flanged bearings (3x6x2.5) now. Works great. I can basically tighten the nut up fully without friction.
Question remains how it will deal with wet mud...

View attachment 10837View attachment 10838

How are you able to fully tighten the nut without it locking up? I tried this and the bearings do not meet in the center because the flange is 0.5mm thick so there is a total of 1mm gap between them in the center of the arm, If you fully tighten the nut it squeezes the center races together and locks up the bearing. It does work great if you are careful and don't over tighten the nut. You'd need a 3xx4x1mm spacer collar in between the two bearings to be able to tighten it down fully.

I tried some 3x5x1mm spacers I had laying around but the ID is too big and touches the outer race. You need at least 4.5mm OD.

EDIT Also I needed a bench vice to fully seat the bearings they are basically a press fit in the arms.

EDIT after trying this I also retract my statement about fixing compound, it's not necessary and the arms are plastic so you don't want to use that anyway. I was thinking the bearings would be set in metal seats for some reason.

Edit i found this aliexpress store that has 3x3.5mm spacers in various sizes: https://www.aliexpress.com/i/3256809291983033.html

 

[Rotauq]

How are you able to fully tighten the nut without it locking up? I tried this and the bearings do not meet in the center because the flange is 0.5mm thick so there is a total of 1mm gap between them in the center of the arm, If you fully tighten the nut it squeezes the center races together and locks up the bearing. It does work great if you are careful and don't over tighten the nut. You'd need a 3xx4x1mm spacer collar in between the two bearings to be able to tighten it down fully.

I tried some 3x5x1mm spacers I had laying around but the ID is too big and touches the outer race. You need at least 4.5mm OD.

EDIT Also I needed a bench vice to fully seat the bearings they are basically a press fit in the arms.

EDIT after trying this I also retract my statement about fixing compound, it's not necessary and the arms are plastic so you don't want to use that anyway. I was thinking the bearings would be set in metal seats for some reason.

Edit i found this aliexpress store that has 3x3.5mm spacers in various sizes: https://www.aliexpress.com/i/3256809291983033.html

I might have overstated 'fully tightened', its certainly not under-tightened.
Adding a spacer is a great idea, preferably the bearings themselves would have been deeper. I was thinking about printing spacers, but the metal ones you found obviously are much better.

In my near-new shiroi the bearings were indeed vice-pressed. At my heavy-used spark (waiting for parts to arrive today) the bearing-seating holes are worn out and will benefit from some locktite.

 

[danl]

Vc3 is an ok “retaining compound” plastic safe solution for plastics. Loctite based anerobic solutions can degrade the plastic.

 

[Atomic Skull]

So like my Asuga my Shiroi came with a wobbly center diff:

I think the problem is they started drilling the screw holes on either side seperatly where previously the holes were drilled straight though and the alignment of the two sets of holes is slightly different where with the older diffs any run-out would match on both sides because the threaded holes were drilled in one go.