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Old 06-20-2009, 05:55 AM   #1
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Thumbs down Steering trouble.

Hey everyone,

I've got a bit of trouble with my steering, hoping someone could shed some light.

In my TA05 I've got a Hitec HS5645MG servo. On the servo I have a Kimbrough #201 servo saver.

Now this is a pretty newly built car, was giving it a few test runs last night at a local carpark for fine adjustments - specially the steering.

I've line it up so both wheels are parallel and pointing forward as much as humanly possible. This way I can minimise the use of steering trim and have a much bigger buffer on the fly.

So all is going well, this carpark is smooth concrete, then all of a sudden my car goes over a bump, and then completely starts leaning to the left quite heavily. So much that if I trim my steering all the way to the right, it is still driving left.

To fix this I had to take off the servo saver, and reseat it. I m guessing it is because the servo saver had moved over a spline or two, but I m thinking such a bump shouldnt have caused this.

If you're still reading, sorry about the essay. My question is, what are the chances of me having a dodgy servo saver? Or a dodgy servo?

Has anyone ever received a servo saver that has lost its spring action, so when it gets hit, and moves over, instead of springing back to the centre, it just stays at that point?

It's really frustrating...
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Old 06-20-2009, 06:46 AM   #2
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if it's the red one your problem is the head of the screw on the hitec servo is tight inside the hole in the kimbrough servo saver. This causes the servo saver to bind and it won't re-center properly.

use a smaller head screw or grind it down so it doesn't touch the sides when fully tightened.
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Old 06-20-2009, 08:05 AM   #3
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Ahh, thanks for the quick reply.

The one I have isnt the red one but I think you are spot on there. I have been tightening the servo saver onto the servo pretty much as tight as I can get it.

I'll loosen it up tomorrow and see how I go.

Is there any other way of testing this other than hitting into something?
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Old 06-20-2009, 08:49 AM   #4
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don't know how your car is setup up with the steering arms and hubs, but with my tf5, i found that if the screws on the hubs in the front (upper and lower) are too tight, it binds the steering. I usually have to keep it tight enough without actually being ovetly tight, which causes it to lean to the tighter side. hope that helps?

just make sure when you unattach the servo connection that the steering is actually free, that nothing is binding its movment. if there isn't anything binding, then its your servo that u need to adjust. if it is binding, you will see what needs to be fixed.
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Old 06-20-2009, 07:14 PM   #5
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I m actually not quite sure how free the spring movement is in the servo saver.

I've tried to hold the inside part, and move the outside part but it is really hard. I dont think I got any movement out of it with just my bare hands.

I wonder how much weight actually needs to be applied to the servo saver in order for the spring inside to move..?
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Old 06-20-2009, 10:01 PM   #6
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Just remove the screw (take care that the saver doesn't come apart, because it's a bitch to put the srping back in), and feel how hard it is to put the screw head in the recessed hole. If it rubs, just sand the screw head around the edge lightly until it goes it without any rubbing whilst you spin it around (otherwise it may not rub in one position, but as you turn it to tighten it might).

While you have the screw out, inspect the protruding collar of the baseplat of the servo saver. If this doesn't protrude far enough through the top plate, it means that when you tighten it, you actually clamp the saver rigid. You need then to shim it.

Before any of these tests, you can just turn the wheels by hand (electronics off) and after the servo reaches the end of travel, push a bit further. You should then see the saver action there (and feel at the hand). When you release the wheels, the saver should spring back instantly. If it doesn't, it binds.

If you have a tough servo, you can do this with the radio and the car on and push the wheels by hand as far as you can to see the saver action. A JR 8715 will cope with this test without flinching.

Of course, you need to free the steering as well.
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Old 06-20-2009, 10:46 PM   #7
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i know this might sound un-related, but check your diff screw(there is a 2x25mm screw that holds the outdrives together). is this is loose, then one wheel will turn faster than the other, causing the car to turn one way when accelerating.
on my yokomo i had this problem(easy fix-just tighten the screw), and i thought it was my servo.
all it took was a small bump, but i think by screw was loose before.


also check the spline teeth, they could be stripped.
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Old 06-21-2009, 01:51 AM   #8
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Cool thanks.

I m pretty sure it's not the diff screw because after I hit something, and it starts going in one direction. I can see clearly that the servo saver neutral position has moved significantly.

I've also checked the spline teeth, they all seem to be in tact and tip top.

I m pretty sure it's just that I tightened the servo saver on way too much. I'll see how it goes next time I have a bit of an accident. Hopefully that's the problem.
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Old 06-21-2009, 02:32 AM   #9
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its not the screw being too tight, its the head of the screw too big usually.
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Old 06-21-2009, 02:34 AM   #10
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Kimborough savers rely on being tight so you might want to be careful how loose you leave it. They have the lower plate neck protruding just enough through the top one so with a tight screw there is still a fraction of clearance between the screw and the top thus allowing for saving action.
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Old 06-21-2009, 06:26 PM   #11
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I m using the screw that came with the servo saver. Right now I've got it on just tight enough so that the servo saver has no movement up and down the spline. Left and right it has a tiny tiny bit of slack.

It came with 3 different heads. One labelled H, I m assuming Hitec. One F - Futaba, and one is A. I dont know what that is. Acoms/Airtronic?

It seems that the Futaba one fits on the tightest, and the H one has the slight slack. The A one doesnt fit at all.
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Old 06-24-2009, 02:59 AM   #12
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Hi again,

Still on the steering side of things.

It seems that no matter how much trial and error adjustments I make, I cannot have the car going perfectly straight all the time.

Sometimes it'll run nice and straight, sometimes when returning from turning right it ll sway to the right ever so slightly, and same thing with the left side.

I've come to the conclusion that it is not possible to get perfectly straight steering ALL THE TIME?

If I can get it going pretty much straight for about 25m, am I doing alright?

I gotta tell ya, steering/camber/toe is by far the hardest thing to get right for me...
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