The Yeti and Trophy Truck are real bad about bending hinge pins.

Bent hinge pin

There are several ways to fix this problem. You can use 4M hardened bolts which require modding the arms and chassis to accept the 4M pins. Use stainless steel tubes in the arms. You can also order the tubes from Strong Arm RC.

I choose option 2 I ordered some stainless tubing the proper size from Amazon, https://www.amazon.com/gp/aw/d/B004XN9O70/ref=yo_ii_img?ie=UTF8&psc=1 on the Yeti I also went ahead and put on a set of RPM arms. You will need to cut 2 pieces of tubing 42mm long. Then drill the arms to 3/16″ keeping it as straight as possible, drill slow so as not to heat the arms to much. Now press fit the stainless tubing to the arms. Reinstall the arms on the truck.

Top RPM a-arm modded for hinge pin Bottom original a-arm

When I built my Score Trophy Truck Kit I went ahead and installed the sleeves right off the bat.

Yeti a-arms after mod