Vaterra Ascender RTR loose servo screw

[LandOfTheEagle]

Do you guys use loctite on servo screws?

I have a problem with servo screw on my Vaterra Ascender RTR. First time it happend a year ago when I run it straight from the box, wheels turned left and they remained like that. I had to unscrew the servo horn and correct it, but it happend few times again until I used loctite. Since then everything was good for the rest of the season, but a week ago I took the truck on a quick trail and it happend again. Well, it happened 3 times to be more specific - good that I had tools with me, but it was a pain to work on it all over again and not to have some fun with the rest of the crew . So, should I use a loctite once again or is there any magic way to fix it?

I have few other RCs and it never happend on any other model, so I will be really grateful for any suggestions. Thanks!

[northernerbill]

If it's the stock plastic servo horn it's potentially being caused by your "end stop adjustment" on your transmitter.

If the servo is pushing the knuckles to full steering travel and then still wants to keep going it will mean your servo horn is being very slightly forced to deform and this in turn will grow a gap between the horn and screw once relaxed in a neutral position.

I would as a matter of course highly recommend an upgrade alloy servo horn which will solve this.

[LandOfTheEagle]

Yes, it's a stock plastic servo horn. Will try it. Thanks!

[Natedog]

Originally Posted by northernerbill

If it's the stock plastic servo horn it's potentially being caused by your "end stop adjustment" on your transmitter.

If the servo is pushing the knuckles to full steering travel and then still wants to keep going it will mean your servo horn is being very slightly forced to deform and this in turn will grow a gap between the horn and screw once relaxed in a neutral position.

I would as a matter of course highly recommend an upgrade alloy servo horn which will solve this.

X2 and my stock RTR plastic horn never broke, but it did need loctited a couple times and really torque the screw down a little tighter than I thought it needed. You can feel the plastic slightly compress as the screw tightens, just enough...don't crack it. Good reason to upgrade to aluminum servo horn as Bill said.

I also found with the RTR radio lacking endpoint adjustment, setting trim to 0, removing servo horn/reinstalling and play with it until it gets best overall even left/right steering and then torque the servo horn mounting screw down good with Loctite will help eliminate the servo strain.

[LandOfTheEagle]

Yea, I already ordered some aluminum servo horns, so hope it will fix the problem. It will probably take a week, so for now I just loctited the old one like last time - should be good for the weekend. Thanks guys!

[Col_Sanders]

I had it happen to me a couple times as well so I installed an aluminum clamping servo horn. It has been fine since I installed that.

[northern hooligan]

Reading your thread I looked at the servo horn on mine, looks to be a Dynamite Alum servo arm... but, the PO never put a nut on the top. No clearance issues at all.

[Natedog]

Clamping servo horn is overkill and most of them get in the way of panhard near full supsension compression, the panhard rubs on them. Dynamite aluminum non-clamping arms are on mine and my SCX10 all without any problems. Replace the phillips-head screw on servo output with a quality allen-head and little washer with Loctite. I put a non-locking 3mm flatnut on the top side of the draglink mounting screw/ball, use a regular 3mm locknut if you have room. I didn't have room with my lower profile servo horn, never had a problem with this setup. Lose the 3mm locknut "spacer" between the steering link ballstud and the arm.

[Col_Sanders]

The Racers Edge clamping servo horns are much lower profile than the Axial servo horn and that is what I prefer to run on my stuff. It may not be necessary, but since I know it isnt going to pop off, its one less thing to have to worry about on a long crawl/hike.

[svt923]

I recently switched to a Tekno servo horn. It solved the problem of the drag link hitting the horn because it is so low profile.

[Natedog]

Originally Posted by Col_Sanders

The Racers Edge clamping servo horns are much lower profile than the Axial servo horn and that is what I prefer to run on my stuff. It may not be necessary, but since I know it isnt going to pop off, its one less thing to have to worry about on a long crawl/hike.

My experience with Racer's Edge clamping servo horns (machined too close to the edge and inferior metal). Racers Edge cracked st both edges where the metal is thin next to clamp screw heads. Axial clamping horn on the right for beef reference:

Originally Posted by svt923

I recently switched to a Tekno servo horn. It solved the problem of the drag link hitting the horn because it is so low profile.

Tekno makes good stuff and that is nice and low profile, close to Hudy.

[Col_Sanders]

I'm running one on my Bomber and if it can survive on that, it will be fine on the Ascender. If either one gives me problems then I will switch to something else though.

[Natedog]

Those were on my Wraith.

[RustyECrawler]

I just pulled my brand new ascender rtr out of the box, and when I powered everything up, and raised the chassis to do a functionality test, the front wheels turn as far as possible to the right. There is no response from the servo when I turn the steering wheel. I can also hear the servo "humming" as if it's trying to turn more. I switched throttle and steering positions on the receiver, and the issue doesn't change. No issues from the throttle in either direction from either position on the receiver. I removed the servo horn and still no response from the servo when attempting to steer. Did I get a "brand new" bad servo?

[northernerbill]

If it's behaving the same on both channels, then yes it does sound like an out the box failure......that's electronics for you (sometimes).

Have you got a spare servo you can lash in to prove?

[RustyECrawler]

Unfortunately I do not, since I'm brand new to rc cars in general and this is my first crawler. Since it's a stock servo and I have to replace it anyway, any suggestions for an upgrade?

[Natedog]

Agree with NorthernerBill. I like Hitec servos and wiu go 300 oz/in or more, not required but nice. 200 oz/in would be my minimum. What's your servo budget?

[northernerbill]

Rusty when your looking for Servos just check the following!

1, look for one that does higher kilo's, many be 15kilo's plus
2, check the voltage it delivers that kilo strength at. Your ESC will provide 5v to power your servo. Some servos look for 6v to deliver their highest kilo strength.
3, you can fit a unit called a BEC which powers your servo independently at 6v but as your new to all this maybe look for one that delivers at 5v for now.

My main point is check the kilo strength against the voltage as this catches many people out, and with this being a new rig, RTR, and you being new keep it simple.

Although Hitec, Savox, RC4WD all produce big strong units maybe consider a hobbyking special to get you moving. I'll look something up if I get time later. Nate do you know one that can deliver at 5v (off the top of your head).

Oh and rusty contact horizon anyway or wherever you bought it to get a replacement!!

Oh oh and you may need to get a new servo horn that matches the new servo.

[Natedog]

X2. I don't know one off-hand that delivers at 5 volts.

[Natedog]

Hitec HS7955-TG is rated at 4.8 and 6 volts.

HS-7955TG High Torque, Titanium Gear, Coreless Ultra Premium Servo | HITEC RCD USA