S-Tuned R/C
Increase the Steering Lock on your MR-4BC (Page 1 of 2)
In standard form, parts of the MR-4BC’s sealed transmission foul the steering bellcranks at the limits of their throw. Follow these steps to get a nice, smooth action, with about 10-20% more lock.
Step 1
The Front Dust Cover (as installed on page 8 of the manual) needs to be trimmed. There are two indentations on it’s top surface, that the steering bellcranks move into at full lock. These both need to be trimmed back about 3mm, to let the bellcranks go to the limit of their travel. I used a sharp knife. This step alone will give you most of the steering lock, however a little more fine tuning is needed to get a nice free action, which won’t strain the servo.
Step 2
I then trimmed a small amount of material from the front section of the dust cover, which I feel fouls very slightly against one of the ball ends on the bellcrank with the servo saver built in. Be careful if you trim it while it is still installed in the car, as the diff pulley is right underneath it. Trimming this part will expose the diff pulley a little bit. I’m not 100% certain it’s necessary - check your car at full lock, and if looks or feels as if the ball end is fouling, trim the dust cover.