This is a very simple tutorial on a quick fix on Faiz' broken knee. Now, for those whose faiz's knee is not broken, please be very careful when you are twisting the knee horizontally. The ball joint is somewhat tight and if you keep trying to twist it horizontally, the stress will be on the hinge joint right above the ball joint risking breakage over there. More often it is the outer hinge joint which will break. Sometimes its the inner hinge, mine was the inner hinge. There are a couple of ways to fix it and I'll point it out here. For my case, my joint broke and I have foolishly glued it shut rendering the entire joint useless. So I have to replace the entire joint altogether. Unless you manage to purchase those replacement faiz joints found on taobao, you will need to use revoltech joints.
Now the first thing you need to do is remove the metal knee cap from the broken joint and glue it on the lower leg (see photo below). You will need to drill a hole o nthe inside of the lower leg ball socket to allow the revoltech joint to go in. You do not need to drill any holes on the upper leg as there is already a hole you can pluck the revoltech joint in.
EDIT: just in case you guys are wondering, you can find revoltech joints in HLJ:
Here is a crucial junction you need to make a decision. Do you use a 10mm single revoltech joint or a 8mm double revoltech joint? The advantage of a double joint is of course more poseability. However, the double joint is way too long and will render faiz having a longer leg than the other (see 3rd photo below). The way to solve this is to cut part of the upper leg away to fit in the double revoltech joint and still maintain a even height pair of legs.
For me I chosed the other option and thats using a 10mm single revoltech joint as the added poseability of a double joint is kinda useless for me (see photo below). Since I have drilled a hole on the lower leg, the revoltech joint will fit right in like the photo below.
I then glue the revoltech joint to the upper leg. I do NOt glue the revoltech joint on the lower leg. I ensure that the hole i drilled on the lower leg is small enough to allow friction to hold the revoltech joint to hte lower leg tight. By not glueing the lower leg to the revoltech joint, I allow horizontal movement for the lower leg. The result can be seen below:
Now, I would like to explain a bit on an alternate method of repairing faiz joint without using revoltech joints. This can be used if there is only breakage on the outer or inner hinge and you did not glue everything together.
For this example, I assume that the outer hinge is broken and that nothing is being glued in place.(see item "A" on photo below, the blue lines represent the breakage
First, use a hair dryer and blow on the hinge joint to allow easier removal the metal rod on the hinge joint and then the lower leg from the upper leg (see item "B" on photo below). The removal of the metal rod can be very tricky. Use a screwdriver to push it out. Use something to lever the hinge so that the metal rod can be removed without damaging further the hinge joint.
Then, get a thin sheet of plastic (you can even use those plastic on plastic bottles) and cut a small wheel the size of the hinge joint out of it with a hole in the middle (see item "C" on photo below).
What you do is sand the inner surface of the broken outer hinge and the plastic wheel to allow better connection for glue. Glue the plastic wheel on the broken hinge joint inner surface (see red line on photo below). The plastic wheel will act as a support for the broken hinge joint. Glue the broken hinge joint back in place. Let everything dry.
Use a hairdryer again and blow on the joint and the metal rod. Reinsert the inner hinge joint between the outer hinge joint and reinsert the metal rod back in place.
You should have a repaired faiz joint again with better support with the metal wheel.
Hope this helps! :)