Crank arm replacement
The crankarm is self-extracting indeed. So, the only tools you will need are a couple of hex keys ― 8mm and 10mm. Please refer to the tutorial below for more info:
Removal of the left crank arm
Use an 8mm hex key to unscrew the bolt that holds the crankarm in place, as shown in the image below (image 1). Note that it will require a lot of force to come loose as we use a threadlocker for extra safety. An impact driver makes the job a lot easier, so if you have one at hand, you can use it too.
As the screw comes out, it will push against a black metal nut that will drive the crankarm out.
image 1
Installing the new crank arm
Hold the crankarm and screw the 8mm bolt (images 2,3 & 4). Please use a threadlocker to secure it in place. And by all means, try to tighten it as much as possible. A good idea would be to use an impact driver to ensure that the bolt is tightened well.
Now put back the black nut (cap), and secure it with a 10mm key (image 5). There's no need to overtighten as with the bolt. Just aim for a firm fit.
image 2
image 3
image 4
image 5
image 1
Installing the new crank arm
Hold the crankarm and screw the 8mm bolt (images 2,3 & 4). Please use a threadlocker to secure it in place. And by all means, try to tighten it as much as possible. A good idea would be to use an impact driver to ensure that the bolt is tightened well.
Now put back the black nut (cap), and secure it with a 10mm key (image 5). There's no need to overtighten as with the bolt. Just aim for a firm fit.
image 2
image 3
image 4
image 5