Front Wheels Bind at full steering

[brennanmac]

First post! I've spent the last two evenings searching for an answer and so far no luck.

I just changed out the stock servo on my recently purchased Gen 8, and after installing I noticed that there's a jitter (best description) as though something is catching or binding in the front axle.

Steps I've taken:

1. Following another users post about axle binding in the CV joints, I took out my dremel and trimmed down the stock axles where they meet the ball in the CV joint so there's extra clearance at max steer.

2. I've checked and double checked the clearance around the tires (Stock). I even dropped my steering rod to mount underneath as they were previously rubbing on the inside of the tires.

3. I've ensured all the CVs are properly greased.

Point to note: when the tires are off, and I crank the steering...there's no vibration or jitter or binding when running. It's only when one or both tires are mounted. This has driven me crazy as it makes me think something on the wheel is catching on the frame or C Hub or something...but nothing is.

Has anyone else noticed or had this problem? I'm afraid to drive it as I feel it will lead to problems later either in the diff or portal axles. There is a definite bind...the whole front axle jitters and vibrates. It's also not rhythmic. I have a video - just not sure how to post it.

Any ideas??

Thank you!

 

[Stormin2u]

Have you tried another servo, just curious?

 

[ferp420]

thats k8nda how they are your using to much steering angle
you clearenced the outside of the shaft but you dident open up the slot were the pin rides so the pin is binding give that little pin more room at the top and the bottom and it.should fix the issue no matter what though its still a week point of the gen 8 easyest thing to do is turn your steering duel rate down to 75-80% and you will have a happy gen8

just turning down the neck of the shaft helps the gear from snaping it dosent eliminate all the binding

 

[JacktheRipper]

How about the steering limit set using the TX, AKA end points

 

[brennanmac]

Have you tried another servo, just curious?

No I have not.

 

[brennanmac]

thats k8nda how they are your using to much steering angle
you clearenced the outside of the shaft but you dident open up the slot were the pin rides so the pin is binding give that little pin more room at the top and the bottom and it.should fix the issue no matter what though its still a week point of the gen 8 easyest thing to do is turn your steering duel rate down to 75-80% and you will have a happy gen8

just turning down the neck of the shaft helps the gear from snaping it dosent eliminate all the binding

Where would I make some room for the pin? In the axel end? Or shave out the CV cup? It’s strange that there’s no binding when the wheels are off...maybe just the small extra weight is enough to cause the pins to catch.

If I turn down the steering dual rate (which I think is essentially the way to set the ‘end points’) even more (I’m already at just over 50% with a hairs width between frame and chub) then it basically eliminates the whole advertised ‘47deg steering angle’. I feel like this is an engineering/design problem that I ‘should’ be able to fix...?

 

[Tylus]

interested in where to shave as well

 

[Timmahh]

I have a stock Gen 8 Axe. No steering issues other than due to the pan hard bar and steering link being just a little long, when the sus compresses, the entire assembly, axle and shocks, will move to the right (passenger side) as it bottoms out the suspension.
If yours is moving enough, perhaps that is causing some binding in the Diff or at the knuckle.

I removed the two outer ends on both the pan hard and steering link and shaved off about a mm of the ball end piece so when I screwed it back on the link fully, it created a slightly shorter link/panhard, and that removed most of the side lash I was seeing.

Just wondering if that may be causing some binding on yours. sometimes only a MM of lash will cause something to bind.
After my shave, I still have a little side movement. so I'll pull the other side (chassis/servo) and shave a mm of those 2 end links.

Too much end point could be an issue too, as that would push the steering cross link into the pumping.
I just setup up my radio last night from Stock settings, and needed to re adjust the EPA on both steering sides. It was going too far, and binding the link on the pumpkin, but that shouldn't cause the axle shaft to bind.

 

[Timmahh]

Ok, I spoke too soon. Steering gremlins are there, just hadn't paid close enough attention to them.

You're correct in your assessment that this is an engineering/design flaw that can be corrected. It will just take a bit.

The Jitters you mention does sound like axle binding. Only thing you can do is remove it, and check out all areas where the pins ride as the axle spins with the knuckle at full turn. Then clearance those areas that are binding but not too much or you'll be buying new axle shafts. lol

Always a trade off. With my Axe, After a deeper look, there are issues beyond the panhard and steering servo link being too long. Bad orientation and poor geometry, and improperly bent links in the steering and pan hard setup are a big part of the problem.

My entire front axle shifted to the passenger side at full compression about 1/4 of an inch, maybe more. Trimming the panhard link ends removed some of it. I still need to trim the steering ends a bit to cut it down a bit more. but too much, and they'll start being too short.

I think I am going to try to find and print a few Angled Rod ends that have a bit more length to them (or buy a pack lol) and then remove and customize the steering cross link to creat more pumpkin clearance first. Then focus on the servo mount and link geometry and see how much of that bad steering and bump steer that can be eliminated, and finally turn to the panhard setup. Im thinking an S curved PanHard bar would eliminate much of the axle shift under full compression.


But that will probably be fall or winter unless it has a major failure before then.