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What is this bolt?!

Discussion in 'General DIY' started by simondyntDBeK, 11 Sep 2020.

  1. simondyntDBeK

    simondyntDBeK

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    I need to replace 12 of these nuts and bolts but am struggling to know what to search for. I'm told they need to be stainless steel (they go underneath a vehicle) and I believe the 8.8 is important? I've measured them as M8x20 but the square 'head' on the top seems unusual (and is important).

    Any tips HUGELY appreciated!

    IMG_2670.jpg IMG_2671.jpg
     
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  3. HERTS P&D

    HERTS P&D

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  4. simondyntDBeK

    simondyntDBeK

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  5. HERTS P&D

    HERTS P&D

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    I just googled it.

    Andy
     
  6. freddiemercurystwin

    freddiemercurystwin

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    They don't look like stainless steel, are they holding the engine splash shield on? If so Grade 8.8 also seems a bit over the top.
     
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  7. JohnD

    JohnD

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    Screws, not bolts.

    And the nuts just look like flange-nuts

    You will need a "stainless steel anti-seize" lube on the threads.

    The "88" means it is high tensile strength steel. Most stainless screws are Chinese and the steel is poor quality. You haven't said what these screws are for, but you ought to buy them from a reputable engineering supplier and specify the HTS requirement.

    As Freddy says, I use stainless for under body shields, but they have no HTS requirement (the parts on mine are plastic).
     
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  8. simondyntDBeK

    simondyntDBeK

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    Thanks gents. I'm starting to understand a bit more!

    They were actually holding on a pair of side step rails on a VW T5 - as you can see they've corroded to buggery and I need to replace them all.

    IMG_2662.jpg IMG_2663.jpg IMG_2664.jpg IMG_2665.jpg
     
  9. JohnD

    JohnD

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    If the slots are corroded, they are weakened and the heads may pull through.
     
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  11. simondyntDBeK

    simondyntDBeK

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    Yeah the garage said they could move the brackets along to a fresh spot.
     
  12. freddiemercurystwin

    freddiemercurystwin

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    Yea that third pic doesn't look too healthy! Can the rails be slid along an inch or so so that the new bolts heads can be mounted in clean metal?
     
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  13. freddiemercurystwin

    freddiemercurystwin

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    Gah! Too slow! :rolleyes:
     
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  14. frutbunn

    frutbunn

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    They don't need to be 8.8, it would only really matter if it was on a suspension component, although the suppliers I use only stock 8.8 in steel. If your going to use stainless you won't get 8.8. Unless the square head is "captive" use standard hexagonal heads then you can just use a 13mm socket or spanner either side.
     
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  15. simondyntDBeK

    simondyntDBeK

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    Brill. Standard hex heads seem A LOT easier to come by. Cheers.
     
  16. frutbunn

    frutbunn

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    [S="simondyntDBeK, post: 4729426, member: 14191"]Brill. Standard hex heads seem A LOT easier to come by. Cheers.[/QUOTE]
    Standard M8's are a doddle to find and cheap as chips, I've actually got a few hundred M8 x 25 I got given!
    Try getting Whitworth bolts, or Japanese automotive metric fines with the correct spanner sizes, cost a bloody fortune!!
     
  17. freddiemercurystwin

    freddiemercurystwin

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    That's assuming the heads of the bolts aren't deeper than the slot and the heads won't turn too much in the slots when tightened - which would beg the question why the manufacturer didn't supply traditional bolts to start with.
     
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