Shimano has quietly updated the bleed port screw on its latest 105 Di2 shifter, finally solving a common flaw that has plagued its drop-bar shifters to date.
Before now, the bleed port screw on Shimano drop-bar shifters was made of a metal that was about as strong as soft cheese.
This was frighteningly easy to round off, and could turn a routine brake bleed into a mind-numbing odyssey.
Any mechanic who says they haven’t rounded one off before is lying through their teeth.
The new bolt, which is currently seen only on 105 Di2 shifters, is made from an undetermined material that feels much stronger than the old bolt. I suspect it’s stainless steel, but I’ve asked Shimano for confirmation.
While I’ve only had the opportunity to remove and reinstall the screw on one bike, the new material feels far more durable, despite the fact I was using an average-quality Allen key.
If you’d like to upgrade your 12-speed Dura-Ace or Ultegra shifters with this new bleed port screw, which Shimano says you can do, the part number is Y0RM98020.
Though it is not commonly stocked by major retailers, you should be able to special-order it from any good bike shop.
Can I upgrade 11-speed shifters to use the new bolt?
Unfortunately, if like me, you’re running an 11-speed groupset, Shimano has confirmed you’re stuck with the old cheesy screw.
This is because the 12-speed drop-bar shifter screw is a slightly different shape that won’t work with 11-speed shifters.
Though I expect Shimano will roll out the new-style screw on all of its future drop-bar groupsets, it’s unlikely Shimano will offer the older 11-speed bleed port screws in this harder metal.
This is a great shame, because I would very much like to swiftly discard the older screws in my Ultegra R8070 shifters.
What should you do if you round off a Shimano bleed port bolt?
If you’ve ended up reading this article because you’ve rounded off one of the older-style bolts, don’t panic – there may be a solution.
After a recommendation from a former workshop colleague, I’ve found good success using Wera’s Hex Plus keys. These have a larger contact zone in the head and offer significantly more grip than other hex keys.
Some hex keys, such as Park Tool’s jewel-like THH-1 T-handle hex keys, feature a clever extractor head that, if used carefully, can be employed to bite into a stripped head. However, these can be a bit hit-and-miss.
You could also try using a similarly sized Torx key in the head of the bolt. This should provide additional purchase, although you’ll want to be careful to avoid damaging the tool.
As a last resort, if all else fails, you can gently tap a Torx key into the screw using a hammer. This effectively creates a new fitting to remove the screw. However, the screw will then be for the bin and you’ll need to replace it.
Shimano definitely wouldn’t endorse this method though.
It’s worth stressing that the threads in the shifter body are very delicate. If you don’t carefully angle the bolt in perfectly straight, you’ll cross-thread them.
If you’ve really mashed the threads it is, unfortunately, probably new shifter time.