A part on my recently purchased suspension called for a 10mm allen wrench in the instructions. Despite the allen key seeming to be too small, I tried it anyways and of course sheared the inside of the bolt (hopefully not so bad as to be unusable).

After this I purchased an 11mm allen wrench, this is too large and won't in fact fit in the bolt at all.

The bolt is integrated into the suspension and cannot be replaced. I am totally baffled, is the part simply defective? What other size options might I have?

EDIT: To hopefully address some of the comments below. The car is a 2008 mazdaspeed3. The part is a spring perch for the rear springs on an aftermarket coilover setup. The bolt itself allows the perch to be raised or lowered - raising or lowering the car. One solution to this is to literally dismantle everything (in which case the adjustment can be done by hand).

I uploaded a video that will helpfully clarify the situation. (photos really didn't illustrate the issue well

Video of the problem

(Sorry for the crappy video, I was filming with an iphone under a car with about 6" of clearance)

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    Pictures and make model of vehicle would be nice, also part you are replacing. – Moab Aug 4 '16 at 21:17
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    Sicne it is slightly stripped now, the 11mm may not fit unless you tap it into the bolt with a hammer – Moab Aug 4 '16 at 21:18
  • @Moab, very good suggestion. Would it be better to delete this question and repost when I have pictures outlining the problem, or simply update this when I am able to get pictures? The 11m is too large, I tried it on both the stripped and not stripped bolt (one for passenger one for driver) – johnchase Aug 4 '16 at 21:20
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    Update this question... no need to delete it – Zaid Aug 4 '16 at 21:32
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    it could be a 13/32" allen bolt. approx 10.3mm but that's not a very common size. – Jasen Aug 5 '16 at 0:06

Grind a taper on a cheap Craftsman 11mm, hammer it tight.

[secrettext] Return it to Sears for exchange when done. [/secrettext]

Where, what and who is this vehicle and fastener??

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    Incidentally this answers the question: Why did that 11mm Allen key I just bought from Sears fit perfectly in this 10.5mm socket? – Jason C Aug 5 '16 at 4:53
  • @SteveRacer This ended up working perfectly. I didn't have to grind the 11mm down too much before it fit, and once it did it was snug. Haven't tried to return it yet though... – johnchase Aug 10 '16 at 17:48
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    @Jason C Because I care; this is how I take care of you. – SteveRacer Aug 11 '16 at 4:25
  • @johnchase Grow some courage and return it using the [secret] protocol. Or even better, Keep It because now you have the right tool. Because I care; this is how I take care of you... – SteveRacer Aug 11 '16 at 4:26

The sentence about the non-replaceable 10mm allen key - bolt made me my head scratching: Could it be that the "bolt" would be the "counterhold" on the top of the shock absorbers? . enter image description here That being the case: Then you do not need to screw it out, you just need to hold it while turning the nut on top of the shock absorbers.

It seems strange to me that in the manual they are asking for a 10mm allen key and that one seems to small. Well, it happened to me once that a brand new torx wrench had not the right size. Either this happened to you or the bolt was produced with faulty tolerances.

Anyway: The head is now rounded.. I would suggest you to use either a matching torx or (better) triple-square bit and hammer it firmly in.

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  • Thanks for the suggestions! I added a video to the question which will hopefully clarify the issue I'm having – johnchase Aug 5 '16 at 16:00
  • Normally when rounded allen-heads happen there are some possibilities to extract them. Since in your case this is not a bolt, but apparently some adjustable part of the suspension an easy replacement seems out of the question. I would suggest you to either remove the entire thing, disassemble it and look if you can replace the "bolt" or address this issue with the dealer and complain about the wrong head size. If both options are not viable i would disassemble it and let some expert weld a nut on top of the bolt so you can adjust it with an ordinary wrench. – Martin Aug 5 '16 at 20:55
  • Attention : the heat of the welding can affect the strength of the bolt, so try to limit the heat impact on the non load-bearing parts of the bolt (tig welding ). If this is also not viable then you just need to buy a new part. – Martin Aug 5 '16 at 21:01
  • I'm hoping that the 10mm allen was actually small enough that the shearing had a minimal impact and that a properly sized wrench will still work fine. I really should not have to apply much torque to the bolt. If it is beyond usable I will strongly encourage the manufacturer to replace it... – johnchase Aug 5 '16 at 21:07
  • I suppose there is a second part on the other wheel? You can check if this 13/32" bit would match in the healthy "bolt". That should be enough argumentation material for the manufacturer to replace it, including costs of labour. – Martin Aug 5 '16 at 21:42

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