Problem with left track of 8043 excavator

[dropship]

I have a problem with the tracks of the 8043 excavator. Basically the left track (the one pushed by the long black axle) constantly stresses the motor and the safety clutch keeps going on and on. When the safety clutch does not engage, the left track is noticeably slower than the right track - when I go forward, after around 1 meter the excavator is visibly turning to the left (I assume that "forward" part of the excavator is the one with the tan bevels).

When I try to move one track to one direction and other truck in the opposite direction (to spin the excavator in one place), the safety clutch of the engine responsible for left track likes to engage like crazy and often the black bevel gear in the central part of the rack will simply fall off!?I

At first I thought it was a problem with my build: but I already rebuild it 3 times since first I had some problems with the switching mechanism (now the switching mechanism uses the mods recommended on this forum - the tan pin instead of the blue one and one grey pin is removed - and works fine), but I still have the problem with left track.

My second idea that it is a problem with the motors or batteries - since I bought the model used, Im not sure if the previous owner did not kill those motors somehow (the one currently operating the switching mechanism seems to be a bit weaker than the others). I tried switching the motors around and it seems that all of them have problems with this track.

Why would the black bevel (connected to the long black axle) fall off from time to time? I went through the instructions like 5 times and my build seems to be fine. I even tried switching the way that the tan bevels.. no effect.

Everything works fine when the tracks do not touch the floor. Please note: Im not interested in the jerkiness of the right track (like most people on the web), there will be always some delay in its work due to its design (driven by the red driving ring).

Did anyone else have such problem or has any ideas where to look - maybe I botched the build somehow... but I dont know where to look.

And yes, I am aware of the "ultimate" mod.

Edited July 5, 2014 by dropship

[Alasdair Ryan]

Have you checked the gearing in the gearbox and through out the whole drive train to the tracks?

You may have the gear ratio upside down.

[dropship]

Have you checked the gearing in the gearbox and through out the whole drive train to the tracks?

You may have the gear ratio upside down.

Thank you for the reply - where exactly?

The tracks look fine; and inside the transmission the tan bevel gears cannot be misplaced.

The only thing I didnt try yet is changing step 36: putting a 6L axle instead of 4L with stop, but Im not sure how this could help (someone recommended it on some other board that I found via google).

[Alasdair Ryan]

I would follow the transmission all the way from the motor to the sprocket while checking for mistakes as you go along.

[efferman]

do you have the first revision of 8043? this had some problems with the tracks because one axle in the uppercarriage was not supported in the right way

[dropship]

I would follow the transmission all the way from the motor to the sprocket while checking for mistakes as you go along.

Did this for like 30th time. Tried to move forward - this time the other black cog fell out..

(the one for the right track, nearly directly under the center of the excavator when you look from below).

do you have the first revision of 8043? this had some problems with the tracks because one axle in the uppercarriage was not supported in the right way

How can I check this?

Edited July 5, 2014 by dropship

[Kumbbl]

@dropship:

http://www.eurobricks.com/forum/index.php?showtopic=88601

(see 4.)

[anton1678]

I had the same problem before, but little experience with Technic, so I just broke the whole gearbox and tried to make it again

Edited July 6, 2014 by anton1678