Why does my front drive shaft / dogbone keep falling out? On my Kraton (edit)

[Primarrma]

I keep having the same dogbone fall out of the out drive at the front diff on my V3 Kraton. I've checked the usual things, pillow ball pivots, ect, I've even removed a spacer from the top pillow ball. I can't figure it out something is flexing under hard steering and popping it out. It seems to always be the same side too. I've got rpm aarms, voltage hobbies towers, gpk chassis braces and front rear hinge pin brace, voltage hobbies steering rack. A few other things, but drive line is stock.

Sorry for the post I'm sure this has been discussed a lot before.

 

[bicketybam]

Which truck? Stock or aftermarket A-arms?

 

[Primarrma]

Which truck? Stock or aftermarket A-arms?

Sorry I've edited the post above, it's on my V3 Kraton. RPM aarms. Thanks

 

[Sledgehog]

RPM arms flex like heck compared to stock on any vehicle. Maybe that's the issue?

 

[Lazy Bushman]

I had that problem recently and it was a tool issue.....that is the tool with the with the hex wrench in his hand?

I run RPM arms up front and have had no issue......all I can think of off the top of my head would be too much play in the pillow balls. When the dog Bones are inserted into the outdrives are they in most of the way into the cup?

 

[Primarrma]

I had that problem recently and it was a tool issue.....that is the tool with the with the hex wrench in his hand?

I run RPM arms up front and have had no issue......all I can think of off the top of my head would be too much play in the pillow balls. When the dog Bones are inserted into the outdrives are they in most of the way into the cup?

Yeah they are when the car is sitting on the bench, but something happens under hard steering and under power that lets them move out. I found a lot of movement between the upper and lower arms. I can kind of twist them a lot back and forth. In and out the tolerance is spot on, but they seem to be able to move forward and back a lot, they seem loose at the top hinge pin. The spacers are all in so I don't know where the slop is coming from.

 

[Primarrma]

I might remove the bottom washer on both arms also to see if it helps? I've already removed the top spacer at the pillow ball thread.

 

[Lazy Bushman]

My RPM arms don’t flex as much as your sounds like they are

 

[bicketybam]

RPM arms flex like heck compared to stock on any vehicle. Maybe that's the issue?

That's my thinking. The only thing I can think of is to shave the arms down a hair to make them shorter.

 

[bicketybam]

I might remove the bottom washer on both arms also to see if it helps? I've already removed the top spacer at the pillow ball thread.

Definitely do that.

 

[2fast4u]

Are your ride height, droop and steering end points set correctly ? Suspension could be over extending a little or turning to sharply one direction or a combination of both. I had that problem once and backed the end points off a little and it hasn't done it since. It was allways under hard braking into a turn.

 

[olds97_lss]

I run the RPM arms on my outcast, never had the bone come out. I run trencher 3.8's which stress things more than stock kraton or outcast tires as they are heavier and a bit bigger OD.

I have noticed over time that my upper front RPM arms have gotten worn where the hinge pins go through. I contacted RPM and they let me buy a fresh pair of upper arms only for when it gets really bad. With the little hinge pin holes so close together, that probably adds to the strain as it allows the leverage of the long arm to twist the upper arm when crashing, stopping, starting, which exacerbates the stretching/wear at the hinge pin.

 

[Primarrma]

I run the RPM arms on my outcast, never had the bone come out. I run trencher 3.8's which stress things more than stock kraton or outcast tires as they are heavier and a bit bigger OD.

I have noticed over time that my upper front RPM arms have gotten worn where the hinge pins go through. I contacted RPM and they let me buy a fresh pair of upper arms only for when it gets really bad. With the little hinge pin holes so close together, that probably adds to the strain as it allows the leverage of the long arm to twist the upper arm when crashing, stopping, starting, which exacerbates the stretching/wear at the hinge pin.

Thanks everyone for your help, I'll try a few things, and check the arms for wear. I will adjust a few things, but I did recently just reset the droop as it was way off the mark.

 

[Primarrma]

So far what I did was, removed the pillow balls from the aarms, reset the adjustment on the pillow ball end caps so there was minimal play, reinstalled everything without any spacers and replaced the shock rod ends as they were stretched. Set the droop and tested it, it all seems ok for now. I'll give it a bash tomorrow to see how it goes.

 

[bicketybam]

So far what I did was, removed the pillow balls from the aarms, reset the adjustment on the pillow ball end caps so there was minimal play, reinstalled everything without any spacers and replaced the shock rod ends as they were stretched. Set the droop and tested it, it all seems ok for now. I'll give it a bash tomorrow to see how it goes.

I had this happen to me yesterday. It happened on a jarring hit to the front end. I'm going to see if it becomes an issue and if so I will do what you have done.

 

[Primarrma]

I had this happen to me yesterday. It happened on a jarring hit to the front end. I'm going to see if it becomes an issue and if so I will do what you have done.

That's a worry, I think it's got worse over time. The rpm aarms are very soft now, but there is a lot of movement at the top hinge pin, as suggested above it may be a worn arm. I have a t bone front bumper I'm thinking of returning it to stock or fitting an rpm bumper. I don't think the front end is as secure as it once was and there is extra movement in the suspension.

 

[Primarrma]

So my test run didn't start out too well and it finished even worse, but in between it was great. My pillow ball pivots pulled out on the first jump, it was from a very poor landing. I fixed that and had a lot of fun for nearly two full batteries, then I must have got an arc happening in my battery connectors, because the solder on two connections got so hot it came apart at the connector, I couldn't believe it. Anyway I'll be able to sort all that out.

 

[olds97_lss]

I might look at the RPM upper arms when I replace them and see if there's enough material to drill out a bit, then jam in some collared bushings like truggies/buggies with king pins in the front use. I'm not sure the size of the hinge pins, 4mm maybe. Not sure I'll find a bushing thin enough to not require too much material to be removed from the RPM arms though.

 

[Primarrma]

I might look at the RPM upper arms when I replace them and see if there's enough material to drill out a bit, then jam in some collared bushings like truggies/buggies with king pins in the front use. I'm not sure the size of the hinge pins, 4mm maybe. Not sure I'll find a bushing thin enough to not require too much material to be removed from the RPM arms though.

I think the tricky part is how close the arm is to the edge of the top chassis plate, it is very thin due to the design, I think anyway?

 

[olds97_lss]

I think the tricky part is how close the arm is to the edge of the top chassis plate, it is very thin due to the design, I think anyway?

If I find bushings and get them to fit, I'll post up photo's of it. If for nothing else, to remind myself what a failure it ends up being. lol!