First we have to lift the 4 pylons in the center. Just keep the Terror Walker to the opposite side and Force Grip them up. This turns off the Walker's shields. Head to him and saber the legs, dashing out of the way when the Walker lifts one to try to smash you. Eventually his head will fall so go to town on that.
When he regains shields 4 fuses on the outer wall will drop out. You need to Grip and Lightning all 4 of these to lower his shields again. Problem is this time there are Spiders and and Terror Troopers in the mix now. Fastest way to put the fuses back is to Lightning the fuse while its in Grip while you are putting it back.
After all four are back in repeat the process of bashing it's legs, followed by its head. This video is from our unofficial game guide. You can view the full guide here