View Full Version : Servo not centering properly

2012.12.09, 04:56 AM
I have a Mr03 that is centering properly.

When I turn left and straighten up it veers to the left a little and when I turn right and straighten up it veers to the right a little.

The slop seems to be coming from the servo gears and the little arms and pins that are on the servo saver so its like a little bit of slop everywhere is adding up. I have noticed a friends MR03 has less slop but I haven't looked in the servo to see where it has less slop yet.

The car is about 1 month old, being used once every 2 weeks so its not flogged out. It just makes it hard to drive because you come out of a corner and it wants to veer in a direction you don't want it to.

Any suggestions on what I can do to fix this?


2012.12.09, 05:25 AM
Must be a chipped on the servo gears. Time to replace it. I have a set for you. I can also get the PN stronger version if your want.

2012.12.09, 06:13 AM
Let the upgrades begin :)

2012.12.09, 10:28 AM
This is something that can be attributed to a loose fitting potentiometer too. All of my F1s did this until I bonded the pot to it's mounting plate with a miniscule dab of glue. I also go to the point of making sure that all of the bulkheads in the servo assembly fit tightly into the chassis so there is no rocking or wiggling. It's delicate work, a tiny razor cut here and there or a smidge of gluestick in some places. Making sure everything is as stationary as possible has always helped with this issue.

I just wouldn't want to see you spend money on parts when alls it may need is a little fine tuning.

2012.12.09, 10:59 AM
Check the servo assembly centering while the tie rod is removed. I've had similar problems from a slightly binding stock tie rod which I had to smooth a bit to free up its movement.

2012.12.12, 06:08 PM
The tie rod is moving smoothly.

I have seen the servo pot gluing trick elsewhere but I didn't think it applied to my problem. I will give it a go and see what happens.

Thanks for the help guys.

2012.12.19, 10:18 PM
any update on this? have a similar problem on 3 awd's (1am, 2asf)

the only difference is that it favors one side... i.e. left turns return back to center, but if i take a right turn, it will veer off to the right a few degrees...

if i trim it straight coming from a right turn, left turns won't center, it will veer off to the left a few degrees...

tried this (http://mini-zracer.com/forums/showthread.php?t=25931) and still doesn't center...

i'm thinking changing the pot or the servo saver next...

2012.12.19, 10:21 PM
and.... i think i'm having something like this now happen to my mr03...

it will go straight... but sometimes wiggle ever so slightly to the left, then right then go straight... took it apart to see if anything was binding... (that was kinda hairy not to mention was a pain to do) and nothing was... put it back together... and same thing... wondering what is wrong... any ideas?

2012.12.19, 11:59 PM
First off, make sure your suspension is not hanging up anywhere, I had a veer before and thought for sure that it was the servo and found that a knuckle was binding.

I've also noticed that sometimes there is a bit of plastic flash left on the servo gears themselves that can cause a slight bind. The flash isn't on the gear teeth themselves, its usually on the flat surfaces towards the center. You may not even be able to actually see it. I usually roll the gears around fully when the servo assembly is out of the car and sometimes you'll feel the bind in your fingers.

There is two fixes I've found for this particular issue, either lightly sand the gear faces or find a gear position where the swing of the final gear doesn't encounter the sticking when it's centered.

It's a fairly common thing for the servo gears to have this, almost all my gears are sanded. I'd say 70% of my cars had this but it's only really an issue when you demand the car goes perfectly straight. I never had my one F1s servo assembly out until around a month ago and I found that it was doing this... fixed it with the sanding method. It's weird, it's almost like the servo motor is at the point where the power is down at center and if the gears encounter this tiny snag, it doesn't get enough juice to get by it.

Poor centering can be caused by so many things and this is just one I've found over the years.

2012.12.20, 03:57 AM
thanks for the suggestion... :D

2012.12.20, 12:58 PM
A local driver was having problems with his servo going crazy once every so often. Turned out the pot wires on the board were pushed around and one wire was shorting out, it was very close so it would short sometimes and there were times when it didn't. Pulled the wires apart and it was fine after that.