I just spent the last day and a half carefully fishing a snapped shift cable ferrule out of my Shimano GRX RX400 (10-speed) lever. In the process I realized I didn’t actually need to fully disassemble the lever, but by then I’d already removed the hinge pin and both C-clips… and now everything is apart.
The lever is completely clear of debris now, but I’m stuck trying to put the hinge pin back in. The spring, piston lever, and spacers all need to line up perfectly, and it feels nearly impossible to do by hand.
My current plan is:
• Use a slightly undersized temporary pin (like a small allen key or drill bit) to hold everything aligned – stack the spring, piston lever, spacers, etc.
• Drop the main lever body into place over that temporary pin
• Push the real hinge pin in from the other side to knock the temporary pin out
• Reinstall the two C-clips
Has anyone here reassembled an RX400 (or similar GRX/road STI) lever after removing the hinge pin? Did the temporary-pin trick work for you, or is there a better method/tool/jig I should be using? Any tips to make alignment easier would be hugely appreciated before I turn this into an even bigger headache.
Thanks in advance!
by slapnut_magoos
4 Comments
This is likely uncharted territory. Many of these devices are assembled with a special jig or tool at the factory that is unavailable to the public making service difficult or impossible. You might get lucky and get someone with the specific knowledge. You plan sounds as good as it gets. In fact your plan is exactly how I swap shimano hydraulic mtb brake lever blades.
You can use a dental pick to align the parts. I used to repair STI shifters back in the day, haven’t tried on that model. Extremely hard to do, good luck.
[Similar assembly](https://youtu.be/BS5Mug7BLDc?si=WLYcNfI5O6Mqj8ji) at 18 min. I’ve never reassembled this exact shifter, but it looks more tedious than older models. The temporary pin strategy sounds promising. Best of luck 🫡
The downside to shimano unfortunately. They’re not really meant to be rebuilt. Alternatively, this is why a lot of people prefer Campagnolo shifters. You can buy just about any part in the shifter and rebuild it yourself.