What I did to fix this problem that your having is.... I heated up the front steering knuckle with a heat gun/hair dryer and inserted a 3mm dowel pin (front or rear sus pin)through them untill the holes lined up
. They seem to be off by about 1~1.5mm and this is where you are getting the binding from...
... It seems that Tamiya never changes the mold from the 1st set of 501x parts...since I have had to do this with every set of knuckles that I have used...
..But after this is done you`ll have a very smooth moving ( non- binding ) steering system
..
Hope this helps
