A few months back, I showed a build video for this MR-03VE with the PN2.5W chassis and some other mods. This car feels pretty solid and clean, except one thing. Despite having PN delrin servo gears, brass 4th gear, and PN tie bar, steering is unexpectedly sloppy. Now, the MR-03 steering design is never going to be 100% free of play, but this car is noticeably worse than my other MR-03. Before the mods, this MR-03VE had seen a lot of miles. Perhaps, other servo components are just too worn out?
Let's pop the servo cover and examine what's going on inside. I'm wiggling the servo back and forth, without moving the servo pinion. I don't see any obvious issue here. If I must scrutinize closely though, the servo saver link/arm shows some slope. Also, the servo gears seem to be a bit loose on their pins? Is it possible the old pins are somehow worn out?
I got these PN servo pins that I didn't use in my MR-03EVO build. I also bought a new MR-03 servo saver unit. Let's see if they will improve the servo precision. There's a lot of tear down in order to extract the servo unit from the chassis. The servo motor itself, buried in the belly, must be loosened in order for the servo to come out. I'm lazy and don't want to desolder the wires. Not being able to really lift up the mainboard makes this tough. Replacing the pins is straightforward, but to shim the servo saver to stiffen the spring, I need to detach an e-clip. The MR-03 e-clip tool is underrated! It works surprisingly okay. I'm going to over do the shimming with 0.7mm worth of shims.
So have the new pins, new servo saver and shims made any difference? You know what, there's definitely less play! I'm amazed. Let's make sure I didn't break any wire during the disassembly and reassembly. There's still play with the steering, as expected. Mini-Z's design optimizes simplicity and durability over precision. When MR-03 is being driven, the play isn't that obvious so in practice it's not a huge issue. But it's nice to freshen up an old servo unit and meaningfully reduce its slop. It feels about as good as it can be now.
This is Sammy and thanks for watching!
Music: "The Hunt", Savfk ( • The Hunt by Savfk (cop... )