Typhon Rear right dogbone popping out

[szafir51]

Hello,

I have problem with my Arrma Typgon 6S BLX. Rear right dogbone is popping out from diff output cup and I don't know why. Only rear right, no problem with left one.

What have I already done to identify the problem:
1. I swapped front/rear differentrials to eliminate problem with diff outdrive.
2. I swapped left/right dogbones.
3. I measured rear dogbones (AR310456), they lenght is 91mm pin-to-pin as in the spec.
4. I swapped left/right wheel axles (AR310431) with bearings.
5. I measured left/right turnbuckles (AR330214)

The problem is only when wheel goes up and rear suspension arm is lifted fully up (full shock compression). It is not connected with droop screw.

I've searched forum for solution but all posts were about front dogbone popping out. Can you help me?

 

[hobo]

weird not got a typhon but got all others never had this problem only at front cvd

 

[MrXD]

A couple things you can do to help is if you have nitro fuel tubing cut some small pieces and fit them inside the outdrives and center your dogbone I do this to all my rc's that have dogbones and another is put some tubing on shock shaft between shock body and bottom cup limit your aarm uptravel a little will help. This should help you out, it looks you covered all your other bases.

 

[SrC]

^^^ Thats one proper fix. But shoudn't be needed in general. Still a good prevention tip. I have used SS springs inside the input drives at the hubs. Keeps the bone further inward to the diff outdrives.
Looks like the OP has a very worn out drive cup though, that is no longer good to use. That is not helping matters.
OP feels it is at full compression when it falls out. It may be happening at compression or just when bashing hard and the rear arms flex to the point the bone lets loose. Adding more shock preload could help.
If happening at full rebound, proper droop will correct this. New arms may also help in this regard. I usually lose a bone at full Rebound or from cartwheels ( arms can twist and flex) if my droop is not correct. My Kraton and Noto. OP def. need new outdrive cups. Preferably M2C upgraded.
One alternative option is use a set of front CVD bones at the Rear. I've done this on a few of my 6s rigs.
You will also need the matching fr. CVD hub axels to do this. Using JennysRC would be the cheapest way to do this.
Edited.

 

[MrXD]

One alternative option is use a set of front CVD bones at the Rear. I've done this on a few of my 6s rigs.
You will also need the matching fr. CVD hub axels to do this.

I do this also now with my typhon and hraton, the typhon front cvds are a little longer, heres a pic of my typhon with front cvd's in the rear and at full compression and its far in the drive cup and theres no binding whats so ever.

messed the quote up that SrC said in above post, lol sorry

 

[SrC]

^^^ This.
This was popular to do here on AF some years past. Not much talk about it these days. But honestly it is the better way to go. I see less inner BB failure in the rear hubs. Bones usually wont pop out. Yet still can if cups are worn, Droop is not correct, and Arms are stretched out. (like RPMS can do with use)
Higher end 1/8 Buggy and Truggy Kit rigs will use CVD's at the rear most of the time.

 

[szafir51]

A couple things you can do to help is if you have nitro fuel tubing cut some small pieces and fit them inside the outdrives and center your dogbone I do this to all my rc's that have dogbones

I thought about it too, but i would like to find a reason in the original configuration before i start modifying the elements.

another is put some tubing on shock shaft between shock body and bottom cup limit your aarm uptravel a little will help

I already did it, I have 3d printed a small rubber bumper and put it on the shock shaft, I think it helped a little. But problem still occurs.

Looks like the OP has a very worn out drive cup though, that is no longer good to use. That is not helping matters.

This is the symptom of the problem, not the cause. I swapped the front differential with the rear one, where the outdrive cups were like new. Dogbone was still dropping out, and now the outdrive cup looks what it looks like.

Adding more shock preload could help.

I don't want to go this way.

One alternative option is use a set of front CVD bones at the Rear. I've done this on a few of my 6s rigs.
You will also need the matching fr. CVD hub axels to do this. Using JennysRC would be the cheapest way to do this.

It's still an option, but first I'd like to try to find cause of the problem.

 

[SrC]

Yeah I saw that outdrive. You get it. I know that outdrive is getting a beating from the popping bone.

 

[szafir51]

I have printed a small insert for the wheel axle, we'll see how it works. Now the dogbone goes about 3mm deeper in the differential outdrive, it shouldn't fall out anymore. Still not a fix to the root cause but it may fix the problem.

 

[szafir51]

Yep, this solved the problem. No more popping out of dogbone.