Bolt Direction

Discussion in 'The Garage' started by Mercury264, Feb 26, 2019.

  1. Mercury264

    Mercury264 Once you go Triple...

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    As I am putting my ST back together after taking the swing arm off to grease the bearings I noticed that I had put the bolts holding the drag link to the place connecting it to the bottom of the shock in the other way round to how it appears in the manual.

    So, question for the engineers/mechanics, does it matter which way a bolt goes in - assuming both sides of whatever the bolt is being put through are the same i.e. nut on one side OR the other ?
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  2. foxtrapper

    foxtrapper Long timer

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    Retention when the nut falls of is a consideration. Generally bolts down with the nut on the bottom.

    Safety when the bolt walks out is another consideration. If it will fall free one way but jam something up the other way, go the free way.

    Access is a consideration, especially upon repair. If it only goes in one way and not the other, go that way. But do consider the above points.
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  3. tbas3

    tbas3 Been here awhile

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    I work on planes for a living. The general rule is bolt heads go up, forward or outboard depending on the choice you have. In the real world does it matter. No. Tighten them properly or use loctite. Bolts in aviation are usually double safetied. The first safety is tighten them properly. Second is use of a lock nut, cotter pin, bendable tab, lockwire etc. loctite is not normally used in aviation to secure bolts.

    When does the orientation of a bolt really matter? Well it matters if there are clearance issues. If something moves and the bolt or nut will contact structure that is when it matters. There are situations where a bolt must be put in the "wrong" orientation for some reason. That is just the way it is and following the rules is not possible some times.
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  4. Mercury264

    Mercury264 Once you go Triple...

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    That is good point when you are talking about a vertical configuration - and makes total sense. In my case, the bolt was sideways so that didn't apply to my situation and access was not an issue (but I have certainly run into that situation before and there was only one way the bolt would go in)
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  5. Mercury264

    Mercury264 Once you go Triple...

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    I definitely get it has to go in a certain way if there are access issues (and I've had that before) but in my case that wasn't an issue - my question was about a situation where I could put the bolt in from either side (horizontally) and there were no access issues so it sounds like, no, there is no difference which way you put the bolt in.
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  6. DSM8

    DSM8 Where fun goes to die....

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    Only thing to look for are clearance issues as the side with the nut will protrude further than the head of the bolt so long as you t wnt hit when suspension cycles your good
    On the Stelvio for that reason it has to go in a specific way on one bolt
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  7. tbas3

    tbas3 Been here awhile

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    My post was mostly about clearance not access. By clearance I mean of its next to something that moves during operation orientation may be important. The nut end sticks out further than the bolt head usually. You have to make sure it will not contact something when it moves. You did bring up something I did not mention though clearance to get a tool in to work on it. Some times its easier to orient things so you can later remove them easier. For example maybe you need to remove a bolt to grease it once in a while. In that case it would be good to put it in so it can be easily removed not blocked by something on the way out.

    In your case it sounds like you can put the bolt in anyway you want.
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  8. foxtrapper

    foxtrapper Long timer

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    Probably not. The original orientation may well have had to do with assembly process on the line. As in grasp part with this hand, grab bolt with that hand, assemble.

    But do make sure said bolt does not do neat things like get into wheel spokes as it works it way loose, or into the chain and sprocket when it falls out.
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  9. spokester

    spokester Long timer

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    Really good answers here, especially tbas3, foxtrapper and DSM8. I might add that there may be rare occasions where the forces working on the fastener may be self tightening or self loosening. Say a wheel bearing started to seize to an axle and unscrew it, or even a suspension link bolt. Is that why you have to remove the mufflers on a Harley to pull out the axle when if the nut was on that side you could leave the mufflers on? My old BSAs have left hand threaded front wheel axles.
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  10. LuciferMutt

    LuciferMutt Rides slow bike slow

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    This is what I was going to say. But if the nut is tightened against a spacer or something, as you said this is on a suspension link, it's probably OK assuming you don't have clearance issues. But if it's bothering you, just take it out and do it right?
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  11. H96669

    H96669 A proud pragmatist.

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    I flipped the lower shock bolt on my BMW.Having to remove and tie up the footpeg/MC mount just to pull out the shock bolt as per the manual?Didn't work for me.
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  12. Zoef zoef

    Zoef zoef Long timer

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    Sometimes a bolt can only be mounted / removed from one direction, you may find out later.
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  13. Mercury264

    Mercury264 Once you go Triple...

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    I had that issue on my Speed Triple - the bolt only had clearance to go in one way, not the other.
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  14. spokester

    spokester Long timer

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    Then there's the BSA that you have to remove the engine from the frame to take the head off, but you have to take the head off to remove the engine from the frame. :baldy
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  15. concours

    concours WFO for 47 years

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    Drag link?
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  16. Ricklesss

    Ricklesss Go soothingly on the grease mud...

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    Ha ha, is that really kind of true?
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  17. small_e_900

    small_e_900 Amanda carried it

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    A friend who used to work on towers said they always put the bolt up from the bottom. That way, if there was no nut on the bolt it wouldn't just sit there doing nothing. It'd fall to the ground and it's absence would be evident.
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  18. victor441

    victor441 Long timer

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    Yep, removing a muffler before pulling the axle is a PITA on a Harley when the rear axle is installed correctly (especially when the muffler has a crossover pipe connected), and FWIW have seen many "tips" on the web advising reversing it :arg. Very bad idea as wheel bearing seizures are not unheard of on theses bikes, the current 25mm bearings are on their third revision. Wish there was a LH thread rear axle available....
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  19. spokester

    spokester Long timer

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    Actually, yes!
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  20. Wentwest

    Wentwest How's that work?

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    Some bolts have a long unthreaded part of the shaft, and I try to be sure that if it's a situation where the bolt carries a load, like at the bottom of a shock absorber, that the unthreaded part carries the load. That's not based on any knowledge, just what looks right to me.
    #20