9398 not driving straight

[datune]

Hello,

I am currently assembling the 9398, and before moving on to the chassis figured I would test drive it. It seems that there is a problem, because it is impossible to steer straight, it always drags to the right, as can be seen in the video. Any ideas as to what the problem might be? Thanks a lot in advance for helping!

http://youtu.be/OIFABgC2tD4

[legomuppet9]

you may not have put the 12t gears on straight. did you follow the instructions PRECISELY? including all the extra sub-assemblies that you take apart after?

[datune]

Well, to the best of my knowledge, I have followed the instructions to the T, incl. the dissasembling...

What is a 12t gear?

Edited August 8, 2013 by datune

[Ape Fight]

My guess would be one of the steering rack gears is one tooth off being centred. Prise the gear away from the rack, move the rack one tooth along, or the rotate the gear by one tooth, and put it back. Hopefully it's as simple as that.

[pint14]

This 12 tooth gear:

[maxxens]

Did you calibrate the servo? It is the first step of the instructions. I cannot see it exactly in your video, but is only one axle or both steering to the side?

If first, forget my comment and check the gears, if yes it sounds like the servo is the problem.

My guess would be one of the steering rack gears is one tooth off being centred. Prise the gear away from the rack, move the rack one tooth along, or the rotate the gear by one tooth, and put it back. Hopefully it's as simple as that.

If i remember correctly the whole rack and the gear is fixed from every possible direction.

[firetech]

In steps 32 and 36, book 1, you have to make sure the 12 tooth gear you add don't put any strain on the (then fixed) steering rack. While assembling my 41999 (same chassis) yesterday, i noticed that if you put on the 12 tooth gear in certain positions, even though the servo motor axle was still in the correct position, it put strain on the steering mechanism, making it unaligned (not driving straight). To solve this, I removed the 12 tooth gears, flipped it and put it on upside down (relative to how it was placed before). Not sure why that helped, but it did.

[datune]

Thanks everybody, I managed to resolve it, as mentioned, it was the 12t gear...