On our Hachette 1:2 scale Terminator T-800 Endoskeleton build, there are some muscles and other bits that do not look quite right. In the case of the lower leg to foot tendons, this is especially noticeable. The ‘piston’ tendon part is very loose inside the muscle ‘cylinders’ and wobbles around when adjusting the foot position:

Thankfully, Ian over at Partwork Upgrades has created a quick and simple solution: his Lower Leg Tendon Fix mod! This is a set of 3-D printed spacers that fit on the ‘pistons’ to center them in the muscles, while still allowing in-and-out movement. When I was assembling the lower left leg late in the build, I decided to install this mod and see how it worked, so that is what this page is all about. I will also install the mod on the completed right leg, so we can see both ways to add this.

Installation During the Build

For builders in the middle assembling the lower legs of their T-800 build (Issue 68 for the right leg and Issue 100 for the left leg).

Step 1

Reach the point where you build this larger lower leg center muscle cylinder for either leg. You will also need the ‘piston’ part which may be supplied in a different issue:

Step 2

Insert the long ‘piston’ part through the narrower end of the cylinder and remove the cap from the wider end, as shown:

Step 3

Super glue one of the large plunger mod pieces to the end of the ‘piston’ inside the cylinder. I found it easiest to stand the assembly on the end of the ‘piston’ which centered it inside the cylinder, as shown:

Step 4

Once this glue dries, replace the end cap on the muscle. At this point, the muscle assembly can be installed per the instructions. When you get to the other leg, follow the same process:

Step 5

For the shorter side tendon ‘pistons’, skip the step where you install the Rubber Washer and screw. Instead, super glue the mod sleeves over the ends, as shown. Once the glue is dry, install them into the cylinders as per the instructions:

Installation After the Build

For builders who have already assembled the lower legs of their T-800 build.

Step 1

At each foot, carefully pop the three lower leg tendon ‘pistons’ up off the ball joints of the Heel, as shown:

Step 2

Slide the large center muscle cylinder off the upper end cap attached to the Lower Leg Casing below the knee. Then, follow Step 3 in the upper section, gluing the mod plunger onto the end of the piston. Once the glue is dry, reattach the cylinder to the end cap on the leg:

Step 3

Pull out the shorter side tendon ‘pistons’ and then remove the screw and Rubber Washer from each one. These will no longer be needed:

Step 4

Super glue the mod sleeves over the ends of each piston, as shown:

Step 5

Once the glue is dry, slide these tendons back up into the side cylinders as before:

Step 6

Reattach the tendons to the ball joints of the Heel. Note how much straighter the tendons are to the cylinders!


This was a minor mod, but it made a huge difference! Before, the lower leg tendons just flop around and tend to end up crooked. It just didn’t look right at all. These spacers keep the tendons centered in the cylinders, so they are always straight. A fantastic job by Partwork Upgrades!

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