I thought this was a closed project... i was wrong!! :]
I decided to change the structure and the geometry of the chassis.
Now the gravity center is lower wich performs more stability.
i´ve decided to remove the other power switchs and put this smaller ones, and one below the other, so that i can switch on all the system at once.
finally i was able to fit the front wheels into the servo, it´s hard to get 2mm bolts so i used this metal pieces, i get the screws from an HD case.
this metal pieces in PC cases, they are used to assemble the mainboard into the case.
i´m using this pieces because i can´t find any store that sells 2mm bolts.
The red part is the important one, and the little piece pointed with an arrow should be bended so that the screw fit into it.
looks like a heavy duty truck : ]
i still want to enforce the white piece of plastic wich is holding the batteries+servo+arduino because it´s starting to bend, and with a servo that is about to be added plus the sonar sensor, means more weight that it will have to sustain.