Recalcitrant bolt resolved

[baz]

Some time back I posted some frustration concerning one of the bolts that secures the starboard side beauty cover on our R-25's Yanmar 4BY2-150 engine. The issue was that one of the bolts simply could not be removed completely. This was because as the bolt was unscrewed and with some 1/4" left for removing it its head would contact the deck's fiber glass. Try as I might I could not remove this bolt. This meant I could not remove the beauty cover. Several Tugnuts suggested various means for resolving this. Today I used one of the suggestions and resolved this issue.

The technique was to unscrew the bolt as far as I could and then using a hacksaw I sawed the bolts head off, leaving enough space to remove the remaining bolt's stud. The stud was easily removed by hand.

I replaced this metric bolt with one that was 1/4" shorter.

Problem resolved… EXCEPT for one problem that bothers me. I tighten the new bolt down but found that when it was fully screwed in it continue to turn, essentially being unable to be tightened. I will need to remove the beauty cover completely to figure out why this happens.

Here's a closeup photo of the recalcitrant bolt.

Here's a wider view of the bolt.

Here's one of the beauty cover's bolt (obviously not the recalcitrant bolt) shown against the shorter one I bought.

Here's a photo of the hacksaw at work.

Here's a photo showing the bolt minus its head 😉

 

[Todd]

Looks like you bought the wrong size replacement bolt.

 

[baz]

Looks like you bought the wrong size replacement bolt.

Thanks… Are referring to bolt length or thread size ? The thread size for the new bolt is identical to the original.

The beauty cover plate is but 1/8" thick so I'm at a loss as to why the new bolt does not tighten up. Removing the beauty plate might provide me with a clue I suppose.

I believe the security of the beauty plate would not be compromised without this bolt, so I may just leave well alone as the object here was to be able to remove the beauty plate when required.

 

[SGIDAVE]

Here's one of the beauty cover's bolt (obviously not the recalcitrant bolt) shown against the shorter one I bought.

Hello baz,

Perhaps it's a photographic illusion, but the shiny new, shorter bolt LOOKS smaller in diameter than the original it is meant to replace. Does the shorter replacement bolt engage the threads properly with the cover off? As in, does the new bolt tighten OK during a 'dry run' without the cover in place?

Just wondering.

/david

 

[knotflying]

That new bolt does look smaller in diameter than the old one.

 

[baz]

Thanks… I will check the new bolt against the old bolt's diameter. I did check that the same nut fits both without slop before I used the new bolt… so will check that aspect again. I do agree that the photo does show the new bolt's diameter being less than the old one.

 

[Don Cardinal]

Is it possible that you are replacing a metric bolt with an SAE?
Don

 

[baz]

Figured the issue... In my numerous attempts to remove the original bolt I believe I stripped one or more of the female threads that the bolt engaged. So will simply leave this beauty plate attachment point without a bolt.

 

[knotflying]

Come on, you have to experience rethreading that beauty!!!

 

[baz]

Not on your Nelly (cockney rhyming slang for not on your life). :lol: