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Both bolts holding my kickstand suddenly broke off (or maybe one did first a day earlier and I overlooked). It is the aluminum frame after 6000 km.

How to repair this? Is drilling and then re-threading safe and appropriate for this situation? Does it make sense to buy and try the broken bolt extractor first (never used this tool before)?

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    aftermarket bike kickstand clamp type - amazon.com/Kickstand-Adjustable-Kickstand-Mountain-eBike/dp/… - The shop didn't recommend something they wouldn't make any money off of, eh? $24 and prob free shipping.
    – Mazura
    Commented Sep 10, 2023 at 20:41
  • Is the objective to have an OEM fix, or that it have a kickstand?
    – Mazura
    Commented Sep 10, 2023 at 20:49
  • Installing a different kickstand may result less stable standing (too long, too short, wrong angle, etc) that is difficult to predict before you buy and install it (another bicycle does not stand well after this way of fixing).
    – nightrider
    Commented Sep 11, 2023 at 5:43

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You'll only have one shot at this repair and have to do it right, twice in a row. As such I see two "safe" options.

  1. Send the frame to a bike shop or someone handy with tools who has done this before. You've not done this before and the risk is reasonable. There will be a cost naturally.

  2. Leave it exactly as-is and ride the bike like normal, but without a kickstand. If you really need a kickstand, fit a different type that secures elsewhere to the frame. The two stubs of bolt won't cause any issues left where they are.

If you're absolutely set on refitting this kickstand, then those two nubs have to come out. Here's how I'd approach it.

  1. Organise another bike to ride while you're working on this one. It might take days, and having another ride means this one can be worked on and left to soak.

  2. Remove the wheels for access, find space to work where you can leave the bike overnight.

  3. Clean the dirt off with water, dry, and then soak down the area with penetrating oil. WD40 is not penetrating oil

  4. Does the bolt poke out from the frame at all? You might be able to get pliers on it and rotate gently. Another option is to use a "dremel" and a thin cutoff wheel, or a hacksaw to place a slot in the end of the bolt for a flathead screwdriver or manual impact driver.

  5. A punch and hammer can help to rotate the bolt on its threads.

  6. You can also apply gentle heat to the area to help the penetrating oil creep better. I use a workshop hot air gun, though a hairdryer can work too. Do not use any kind of open flame because it will damage the paint.

  7. Patience and Gravity are tools too - soak it in oil again and leave to stand overnight.

  8. Graduate to making holes. If you have access to left-hand drill bits, they can be useful here because they will push against the stuck threads. Be very careful to be centered (a punch mark to start can help). Start with a 3 or 4mm hole, so it doesn't risk touching the threads of the frame.
    A pro machine shop would make a flat spot with an endmill or a center drill or spotting drill and then go in.

  9. At this time you might try your "easy out" but in my experience they're not likely to help. Do NOT hammer them in. Use a tap handle to turn them so you get feedback. If the easy out snaps off, it will be even harder to fix this.

  10. Next is to drill out the entire core of the bolt stub but only just grazing the frame's material. This should leave a spiral of metal from the bolt in the frame which you pull out like a string. This drilling op must be straight and centered. Then "chase" the threads with the correct tap.

  11. So you've drilled into your frame and the thread is damaged. Your only option here is a helicoil thread repair. That's certainly possible in the home shop, and I've done it but too complex for this answer.

Finally when you have both stubs out, use top quality high-tensile bolts. Avoid random bolts from the gack box, get yourself some grade 8 bolts of the right thread and length. This will stop the bolts from snapping again.

When you do reassemble, use copper clay or a good grease between the bolts and the frame. That will limit corrosion in the future.

Good luck !

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    Re #11: instead of using helicoil, simply drilling up one size (M6 to M8) would be another alternative where bolt size is not important. Looks like there's enonugh material for that.
    – vidarlo
    Commented Sep 10, 2023 at 17:24
  • @vidarlo good idea - also depends how much meat there is on the kickstand to enlarge the holes there.
    – Criggie ♦
    Commented Sep 10, 2023 at 19:34
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    Strongly agree that WD40 IS NOT PENETRATING OIL. One good thing about the drilling approach is that very often the inside of a bolt is softer than the outside, since the threads work-harden when rolled. I've got reservations with Helicoils into alumin(i)um on account of the potential for corrosion (dissimilar metals, salt from road, etc.).
    – Mark Morgan Lloyd
    Commented Sep 11, 2023 at 6:31
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    @MarkMorganLloyd excellent points. Real helicoils are stainless steel not plain steel, so are lower differential on the galvanic scale. I always slather the thing with copper clay which also works as a water excluder and isolator because its non-conductive. Personally I'd go without a kickstand, but that's just my biases.
    – Criggie ♦
    Commented Sep 11, 2023 at 7:08
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    There's another benefit to a left-hand drill - or perhaps another way to state it: If you use a normal drill, and the screw starts to turn, it will be driven into the frame where it will rattle forever unless you get it out through the BB housing. If you use a left hand drill and it starts to turn - that's what you want. Because the steel of the screw should be drilled fast, you won't have much time to react if it starts going inwards. Also the snapped remains could damage the thread if it starts going it
    – Chris H
    Commented Sep 11, 2023 at 14:14
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With the heads gone it's likely there is no thread preload. There can still be significant friction to overcome from either loctite or other issues with the threads. Cutting a screwdriver slot in with a Dremel is a common first step if it can be done safely, which in the right hands it likely can. Screw extractors would be the next step if not, but are more work. Putting light heat on from a hairdryer will help if there is threadlocker that needs to be overcome.

My favorite tool for this if it does need to be drilled out is a carbide burr in a Dremel. Left hand twist drills of an appropriate hardness could be good too. Getting something sufficiently harder than the bolt can be tricky.

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