Requesting Advice: Screwed Up Suspension Bolt On Final Drive

[Lupin62]

Hi All,

Long time lurker here, I've only posted here a few times but I know you guys are extremely helpful.  I'm writing because I screwed up a standard suspension swap and need advice.  Rookie move, eh?

Without going into too much detail, I bought some Progressive 412's for my bike because I had one bind up on me when trying to adjust it.  I took the stocks off but ended up tightening the bolt instead of loosening in the final drive, you probably see where this is going.  Long story short I tried drilling the thing out but only made it worse.  Right now the head is stuck in the rear of the hole with no way to get it out and I believe I stripped out the threading.

My question is this: My final drive was in really good condition other than the bolt fiasco.  Do I just part the thing out and bite the bullet to spend $450+ on a new final drive now?  If so what can I part the inner components out as to recoup at least some of my cost?

I'm very leery about drilling the hole out and thread locking in an insert like I see other people here do, seems dangerous.  If you've done this can you comment on how it's holding together?

[matt]

I would find a machine shop that will drill it out for you. They have clamps and drill press. Sometimes they can even extract bolts and save threads. There are a couple different types of heli coil or thread inserts. Tell them what its for and they will more than likely point you in correct direction

Matt

[Skinhead]

Where are you located?

With out pictures, it is hard to give advice, but if I understand you correctly, it sounds like you broke the lower right shock bolt off in the final drive?

If so, I would try to drill it out from the opposite side (I don't recall if there is enough clearance to get to it from that side).  Use a drill size that is correct for tapping new threads in the final drive housing and buy a new bolt.  If you don't have the tools, take it to a machine shop.  They should be able to help you out.

[da prez]

Put a location on your avatar. Most of us are in witless protection,  so you will fit in. There is someone near that can help.

          da prez

[Lupin62]

Photo for reference.  I'm pointing at the hole in question.  Note that I tried to drill it out the back at first when the thing was on the bike since I saw a hole.  It's not the full size of the bolt head, only half    As stated it's now stripped out on the threading since I discovered the magic of left handed drill bits too late.  I'll post on that later as info for anyone stumbling on this thread down the road since that would help immensely to start.

I'm out of Pewaukee, WI currently if that helps since someone asked my general location.

https://drive.google.com/file/d/1DRIPvDEh5ewTfv438Z8pNLW0tlzuxusM/view?usp=sharing

[The emperor has no clothes]

Photo for reference.  I'm pointing at the hole in question.  Note that I tried to drill it out the back at first when the thing was on the bike since I saw a hole.  It's not the full size of the bolt head, only half    As stated it's now stripped out on the threading since I discovered the magic of left handed drill bits too late.  I'll post on that later as info for anyone stumbling on this thread down the road since that would help immensely to start.

I'm out of Pewaukee, WI currently if that helps since someone asked my general location.

https://drive.google.com/file/d/1DRIPvDEh5ewTfv438Z8pNLW0tlzuxusM/view?usp=sharing

Once you get it drilled and tapped you will need a spacer/collar to take up the space of the original mount. Also, be aware that it needs very little tightening. That mounting bolt is just to hold it in place.

It would probably be worth it to take it to a machine shop, so as not to screw up the rear end case.

[Pluggy]

Removing the damaged bolt takes some experience and this is not a good part to learn on.  Damaged threads can be replaced with a heli-coil, and that requires a special tap that is fairly expensive.  A machine shop, particularly one familiar with import cars should have that.

You can start the process by ordering a new:

BOLT, RR. CUSHION 90159-MG9-000

If you go to a machine shop, take that bolt along to show exactly what needs to fit in the threaded hole.

Best of luck with it.

Pluggy

[steveB (VRCC UK)]

The way I do this after enthusiastic owners have sheared the M8 threaded portion in the box is to take the old bolt and face off the threaded portion back to the shank. Bore a 6mm hole centrally in the shank starting from your newly faced off end, right through. (I do this on my ancient lathe but its a 10 minute job in any machine shop). Insert your newly fabricated template into the box and drill through using a 6mm 'good' drill bit. (I use a high speed air drill but any reasonable hand drill will work). Finish off by cleaning up the threads with an M8 tap or thread chaser. New bolt part no 90159-MG9-000 plenty of anti-seize and minimum force.
 

[Pluggy]

The way I do this after enthusiastic owners have sheared the M8 threaded portion in the box is to take the old bolt and face off the threaded portion back to the shank. Bore a 6mm hole centrally in the shank starting from your newly faced off end, right through. (I do this on my ancient lathe but its a 10 minute job in any machine shop). Insert your newly fabricated template into the box and drill through using a 6mm 'good' drill bit. (I use a high speed air drill but any reasonable hand drill will work). Finish off by cleaning up the threads with an M8 tap or thread chaser. New bolt part no 90159-MG9-000 plenty of anti-seize and minimum force.
 

Steve, that repair is why guys take it to you instead of trying it themselves.  It is a delightful solution if there's a lathe parked next to the motorcycle in the garage.  Making a tool from the damaged special bolt is a great idea, provided you can drill that hole through the bolt really straight.  Now, if the threads are damaged beyond repair, what's next?  Another opportunity for a well-meaning bike owner to possibly screw up.

You know the term "bodger".  Translation: a guy in over his head.  Our owner can best get back running by paying a man (like yourself) with the skill and equipment.  He may want to take the bolt-tool idea along with the damaged part.  Cheers.

[Bagger John - #3785]

17ft-lbs; de-rated slightly if anti-seize is used.

Right after a correct set of sockets, a collection of calibrated torque wrenches should be the next tools in any mechanic's toolbox. Proper use of them will greatly reduce the likelihood of broken bolts or thread pull-outs.

I put a dab of anti-seize on the threaded portion of the fastener in question and use a good high-temp silicone grease on the barrel portion which engages the shock bushing. Recently removed one of mine which has been in position for almost 14 years; it freed up and came out without issue.

[steveB (VRCC UK)]

Pluggy - thanks, very flattering but I would consider it an honour to be called a bodger.
 

[Pluggy]

Steve, I have heard the term bodger, as applied to motorcycle owners to mean:  Someone who is over-confident when it comes to fixing something and usually creates a much larger problem.  Heard it sometimes from British bike friends.  Am I using the term correctly?

In US Aerospace we said "Maintenance induced failure". Something broke, unplanned, while work was performed.

[Warlock]

Use a left hand drill bit. One just a little smaller than the broke off dutchman. The make a extractor that will then fit the hole and you turn it counter clock wise and it digs into the dutchman and most of the time it will back right out.
https://www.lowes.com/pd/SpeedOut-8-1-8-in-Double-Ended-Screw-Extractor/1000170531
David

[steveB (VRCC UK)]

Pluggy - your use of and definition of the UK term bodger (and by extension 'to bodge' ) is correct. Here in the UK you might also here the expression 'its mullered' ie bodged beyond repair. BTW Glynis (the SO) says its the Valk parked next to the lathe not other way round. And yes I too have had many 'Maintenance Induced Failures'.

[Bagger John - #3785]

And yes I too have had many 'Maintenance Induced Failures'.

For a good case study, look at United Airlines 232 (the anniversary of which was yesterday).

People tend to think they're smarter than the engineers who design and document equipment maintenance routines. Some times they are. Sometimes it catches up with them.

[rug_burn]

    I second the left-handed drill suggestion: broken-off bolts often come out just with the drill alone.   But this requires the right tools,a steady hand, a pilot hole, a few sharp drills and experience etc.   If the shaft of the bolt is still on, and the aluminum threads are totally stripped, you'll have to push it out from the backside while turning the head of the bolt.    It may be a lot easier to take it to a good machine shop than attempt that yourself.

   And helicoils (thread inserts) work great if done right, since they spread out the bolt stress to a larger diameter, and therefore larger stress area which is actually stronger than the original setup, especially in soft materials like aluminum...    You can get them in a variety of lengths and materials; ideally the same length as the thread engagement area.   Again, this might be a good shop job.  But if really you're interested, you could do it yourself, and we could offer advice from afar.   I just did one on a water pump mounting on my truck.

   Don't beat youself up over it- the only ones who've never broken off a bolt are the ones who've never tried to fix something.