moebiusfactor

Recently I've been having a bad superstructure slewing problem. I imagined once again it may be a gear issue or even the M-motor itself. It turns out that (sometimes, not always) the batteries are to blame. As we all know, 8043 is a thirsty little thing- it eats power like no tomorrow. And since the M-motors are not that powerful in the first place, the slightest drop in amperage from the batteries will cause them to be sloppy in their performance. I tried using the 8878 rechargeable battery I've been using in my TAS batmobile- not only the superstructure spinned a lot faster, but the overall performance of the M-motors was indeed far better. And, just got an email from Lego, it says the parts (4 LAs) will be sent out early October to all customers with the 8043 set.

When I contacted Lego the other day they told me they are simply replacing the current LAs with the updated ones (someone here raised a good question as to if they will look the same as the current ones or not)- and they put me on the list to receive the parts as well (4 LAs)

Well, I'm surprised too, actually- and your instructions were very helpful, spared me hours of frustration, so I thank you- I think TLG should take a strong note of this.

I chose to do a little investigation of my own so see if indeed the M-motors are to blame, because I simply do not believe The Lego Group would mass-produce a product that wouldn't work- if the designer of 8043 said that the M-motors should take the pressure, then they have to- that they do it less efficiently than the XL motors, that's a whole other story. So, after fighting my way through the internals of the excavator I made a discovery most sinister. Two grey 16-tooth gears transfer the power from the far left motor (if you face the excavator from the back) to the left-hand tracks. One of these gears are held by a tan pin that is not secured by the bottom, so it will slide out eventually with time. It explains why when I first built it, it ran well, and got progressively worse. What I did was basically remove the tan pin and the grey shaft from the second gear and replaced the tan pin with a size 3 shaft and the grey shaft (from the second gear) with a size 6 shaft. All is left is to secure the bottom. This mod was based on Jurgen's modifications of 8043 (see his Ultimate 8043 post, it is magnificent work). The result was fantastic performance from the left track, and the excavator's speed increased dramatically as well, since both tracks move at the same speed without any strain. This is worrying however, because this is a design flaw that can result in gear/motor damage if left unchecked.

So how can the slewing problem be explained? As of now, the left-hand tracks (if u're looking at the excavator from behind) are barely moving- this is with fresh batteries. Is there something mechanical I'm missing here, like, aren't both tracks supposed to slew at the same time?

Are you having the issue of the left track moving slower than the right track? I'm still not sure whether it's supposed to be like that. On full batteries it works better, but it still moves slower than the right track.

This is great, wonderful work! But now, the question is, you've done so much with this model- perfected it pretty much- and much of the negative discussion surrounding 8043 is its LAs. Clearly, Jurgen used the same LAs and they don't seem to have any problems. Odd.

I just checked this out right now, and it seems the far left motor controls the left track, which is struggling as if it's under massive pressure; (the motor next to its right seems fine, which may explain why the right track moves so well without any strain) but when I switch to the LAs, they all struggle. At the beginning there was very little struggle in any of the LAs and motors, and I don't recall the far left M-motor functioning this badly. Idk, but I hope the issue with the LAs haven't damaged the motors.

Hey everybody, I just joined, in fact, I had to- the alarming number of complaints on this set scared me, and since I have a few issues of my own, I had to know. Apart from the LAs, From day 1 I had the problem with the left track working at a very slow pace- now, it's as if the motor is struggling to turn it, when on the right, it all works fine. I only know so much about mechanical engineering- is this supposed to be normal?