slaphead

[]I was bashing my Marder (stock Race model) yesterday and after only a few minutes it grinds to a halt, the engine still revs away but it's not going anyhere. On looking at it everything appears to be going round except the wheels, i.e the pinion and spur are spinning as is the large gear on the diff but the wheels are not turning.
I had this once before and stripped the diff to pieces couldn't see anything particularly wrong and put it back together and it worked fine again until yesterday when as described it did it again.
I haven't pulled it to pieces again yet but does anyone know a likely cause and a cure for it, do I need the alloy diff housing or any other parts to stop this happening it's beginning to brass me off.
Any advice gratefully received.[]

DERF-54

My Feedback: (48)

Sounds to me like the square drives for the wheels are spinning on th shafts. Check this before you go anyfurther, also you can replace them witth the steel ones from the duratraxx.
Derf

-barcelona-

Funnily enough, after a hard days bash, this also happened to me yesterday!

I thought I had smashed the diff internally, but after a full strip down jobby, I found the cause to be the pinion gear and the spur gear (steel) that had come loose.
It span the wheels when I picked the car up, but under load when all the wheels were in contact with the ground, it was just spinning

Tighten all the grub screws on all the gears, and it should be good to go ...I hope !

carpy100

yeh wheel squares prolly mate.

bigger the better

If all is moving all the way to the wheels you stripped out the grub screws in the wheel squares. Believe me after 6 sets I know the way to do this so they last. 1st if they come out without stripping the aluminum threads you will need to do the following:

A. Remove screws. Be careful they may be spread in the hole and when you back them out they will strip the threads - You may need to screw them in till they fall out the inside if thats the case.
B. If the original are only rounded off a little you may be able to reuse them - If not go to the hardware store and find the isle with all the hardware in the plastic bins, find the metric grub screws and get replacements. Or you can drill them out and retap them whatever size larger you want - I had too since they where on back order and the LHS was out (NEED TO PLAY[>:])
C. You must file down evenly the end of the grub screw so that it is flat with no bevel left. Usually to the first set of threads. This will allow it to sit flat with a larger surface against the axle.
D. Install locktight on the threads of the screw and a little in the square, just for good measure.
E. Tighten them down good and tight.

Good Luck!

carpy100

must also reccomend the steel squares. you can tighten them rite hard and they dont strip or move. alloy ones are cr@p

bigger the better

I agree, where can you get the steel ones for the MT - Next time this happens I'm switchin!

bigger the better

Oh ya, the easiest way to file I found was to take a single allen key and insert it into the grub screw, take a file and set it on a flat surface, drag the screw back and forth and twist the allen key every so often to even the filing. You will see in the pictures there is a hole in the center of the screw, you will want to file till that disarpeers then you are done.

carpy100

stan at rapid racing does them and will ship. i got the 14mm to widen the track, made hell of a difference on the marder (you have to fit elcon medium axles on the front tho). dont know how it would work out on the trucks etc?

Acs_guitars

My Feedback: (3)

the drive squares for the Firehammer are steel and are slightly thicker than stock FG.... I got some when I bought the FH wheels and tires, $15 from Tower, they work with the MT wheels I have too same as stock.

bigger the better

Thanks guy's!

bigger the better

Did you use the FH wheels on your MT?

Sorry slaphead for hijacking you post. []

Acs_guitars

My Feedback: (3)

Nope... MT wheels on a Marder. I have FH wheels for my Marder because they are ALOT cheaper than FG and same quality.

slaphead

[&:]Well you guys you were right it was one of the crappy, crappy wheel squares, I'd already had to do one and now the other. i appreciate the advice and if Ican find the Rapid Racing site I'll replace them with the steel version, meantime while I'm waiting it's out with the file on the grub screws!