28 September 2018

Axial SCX10-II (AX90046) shock rebuild

As you may have read in Part 1 of my review / build report of my Axial SCX10-II (which you can find here), I wasn't too thrilled with the shocks. I took a lot of care assembling them, but they didn't perform like they should. I didn't want to invest in a shock upgrade right away on a new kit, so I decided to rebuild them. Just like the build report, It's been a while since I did this rebuild, but I managed to reconstruct most from forum posts etc.

Ok, this is a bit of an open door, but I started by taking the shocks off the chassis. Once all four of them were on my workbench (a.k.a. kitchen table), I opened them up, dumped the shock oil in a jar and inspected all components of the shocks. On one shock piston, I found a bur that I had apparently overlooked during the building process. That was quickly fixed with an exacto blade. I couldn't find anything wrong with the other 3 shocks.

I decided that for the re-assembly of the shocks, I was going to use the shock caps without the faux-piggyback-reservoirs. I figured that they'd make for less places to get muck stuck while driving. And being a tiny bit easier to screw on straight was just an added bonus.
I pried the o-rings from the previously used shock caps and inspected them for damage. They looked good, so they were installed in the new shock caps.

Now the process of filling them again started. I'm a patient man, but getting all the air out always gets on my nerves. I filled the front shocks with the 30wt shock oil provided in the kit. After I was certain there was not a single air bubble left in the shock, I put a few drops of oil in the shock cap, filled the shock body until the oil literally bulged over and carefully screwed on the shock cap. And cleaned up the excess oil that by now was all over the place.

One rebuilt shock

Victory! The first rebuilt shock was perfect. My guess is that without shock diaphragms, some air bubbles had remained in the cap on my first attempt. I repeated the process for the other 3 shocks, but for the rear shocks, I used a 20wt shock oil as the weight of the SCX10-II is biased to the front.

When I built the kit, I found that the spring adjustment were binding on the shock hoops. So I wanted to add some shims to fix the problem. I was running low on shims and didn't want to waste any where another solution might work. So I looked through the left over plastic bits from the kit. It turns out the rings that usually go between screw and body on the models where a rollcage is installed, were a perfect fit.

With the rebuilt shocks back on the chassis, the handling and flex had improved a LOT. I'm very happy with their performance now, but I do wonder how long they will last, as I read a lot of reviews mentioning leaks and other problems.

1 wheel 10cm (4") in the air, the other 3 planted on the table, it didn't do that before


So far I've been running with these shocks for about 6 months, and so far, there have been no signs of leaking.



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