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Broken rear lower shock bolt....08'RT


I812

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Broke right in the center of the shock mount. Found the bolt hanging out and thought it had backed out. Can't get the shock off with 1/2 the bolt still in there Any ideas?

Thanks in advance!

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Afternoon 1812

 

You have one of those "sort of need to be there & see/work with it" to give you a solid idea.

 

As a quick reply personally I probably just find/make up a sleeve to fit through the hole & shock where the broken bolt came out of then center drill that sleeve with a 5/16" hole right on center, then insert that sleeve & use it as a drill guide to drill into the broken piece using a left hand 5/16" drill bit.

 

If the broken part isn't cross threaded or jammed in there too tight it should screw right out as that L/H drill bit enters it a short ways & catches.

 

The secret here is to be able to adapt & change directions quickly if what you are doing doesn't seem to be working.

 

A machine shop can probably get that out fairly quickly if you don't feel comfortable doing it yourself.

 

Just be careful doing it yourself, if not done with care & caution you can make it worse then it will very difficult to remove.

 

Added: you need to have "0" (or no) load on the rear strut when doing the above. Any load on the strut at all will make the bolt bind & not come out easily.

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Thanks for the fast reply DR! The dealer talked about installing a heli coil. 3 week wait and I have riding vacation sooner. I don't have the tools or room to do it myself but I have a good local mechanic and I will pass your info on. I do have L/H bits though...:)

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Don_Eilenberger

One caveat..

 

Although with the clamping pressure released by the end of the bolt falling off it should spin out easily, this bolt is supposed to be installed with Loctite medium strength.

 

HEAT would be your friend, although how to heat it might be a challenge. About all I can think of is after partly drilling the hole, if it doesn't spin out with the reverse drill bit, use a pencil type soldering iron to heat it up - sticking the tip down in the drilled hole long enough that you start smelling some burning smell.

 

Then try the reverse drill bit again, or - an easy-out.

 

This is really an ugly situation. Do you know who torqued it down last time? This really sounds like a rare sort of failure (the bolt torques down on the sleeve on the lower shock mount, and pulls it tight against the inner wall of the swing-arm recess.) I can't imagine it failing unless the bolt was defective, or badly over-torqued (ie - GutAndTight..)

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Ugly is right. Hardened bolt will be tough to drill. Annealing would help but with the shock there not is not going to happen. :mad:

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Evening 1812

 

That bolt is a little softer in the middle so with a good sharp bit should drill OK. You don’t want it to drill too easily as you need the heat from drilling to hopefully allow the LocTite to release.

 

If the bolt has been broken for a while & you have ridden the bike it’s possible the remaining part has seen enough loading changes to have worked in the threads & loosened a bit.

 

I have heard of a few rear strut bolts breaking like this so it is possible your dealer has done a couple already.

 

A good machine shop should have no trouble getting it out as long as they can get access (some don't like to lay on the floor to work). Neither a machine shop or dealer will be cheap as it could take some work or even cutting the lower strut spool with a mini air saw or something similar then drilling the swing arm & installing a Helicoil.

 

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My rear lower shock bolt was discovered broken when I changed to a Wilbur shock. (Scary thought... How long had that bolt been broken???) Since I was being lazy and having a shop do the shock change, the shop removed the swingarm and sent it to a machine shop that successfully drilled the remainder of the bolt out. This was actually a last resort as an edm machine would have been first choice, but none were available in the area at the time.

The machine shop managed to save the threads, and no helicoil was required.

BTW, the shop had to saw through the shock mounting bolt between the shock and the swingarm to be able to remove the shock preparatory to removing the swingarm...

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That really is a nasty one.

As I'm fiddling with the suspension on my GS, I'm now tempted to replace that bolt just as a precautionary measure.

For a home mechanic a broken lower shock bolt would be a real bummer.

 

--

Mikko

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This is not a rare occurrence! Mine has broken 2x. The 3rd one is broken and still in there. I did exactly what DR said, drilling out the old one and replacing with a new OEM bolt. They seem to break if the head of the bolt does not fit tightly inside of the outer swingarm casting. This allows the bolt to flex slightly and eventually breaks. I give up! I am leaving the broken one in there! The shock cannot go anywhere with half a bolt still holding it. I have about 10,000 miles on the broken bolt.

Rob

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This is not a rare occurrence! Mine has broken 2x. The 3rd one is broken and still in there. I did exactly what DR said, drilling out the old one and replacing with a new OEM bolt. They seem to break if the head of the bolt does not fit tightly inside of the outer swingarm casting. This allows the bolt to flex slightly and eventually breaks. I give up! I am leaving the broken one in there! The shock cannot go anywhere with half a bolt still holding it. I have about 10,000 miles on the broken bolt.

Rob

I don't think that is the best solution. Catastrophic results could happen!

This could be a design/manufacturing flaw.

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I don't think that is the best solution. Catastrophic results could happen!

This could be a design/manufacturing flaw.

 

Yeah...the best solution is replace the swingarm. Ain't gonna happen!

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I don't think that is the best solution. Catastrophic results could happen!

This could be a design/manufacturing flaw.

 

Yeah...the best solution is replace the swingarm. Ain't gonna happen!

The bolts have been able to be removed apparently.

Just seems like I said.

Flawed.

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I would like to find a replacement bolt grade 12. Cant find any info in my CD manual....

 

Morning 1812

 

There is no grade 12, 10mm metric bolt that I know of. There is a grade 12.9 though.

 

On the length & size- my manual shows it is 10mm X 80mm but no pitch given. It's probably the standard 1.5 pitch as fine thread is seldom used in softer alloy material.

 

The big thing here is correct bolt head diameter as the bolt head seats in the outer hole as part of the load carrying so if too large it won't go in & if too small it will allow bolt movement & possible bolt fracture.

 

I show the stock bolt is only about $3.50 so you might buy a stock bolt then match a generic grade 12.9 to that.

 

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I recently pulled my shock to try fixing an ESA issue and found a couple things that might be helpful here.

 

The BMW repair DVD calls for heating the lower strut bolt/swing arm area to 100C with a heat gun before removal - I presume this is to loosen the Loctite on the threads. So heat may help here if you are using an EZout/left hand drill type tool. I realize the broken bolts discussed here broke while in use and not during removal, but knowing this might prevent others from breaking their own weak bolts.

 

Also, the DVD calls for applying Optimoly TA (aka spline lube) to the "screw heads" on installation. I'm interpreting this as the non-threaded portion of the bolt, where the shock pivots. I would expect lube on the underside of the cap head to lead to over-torquing the bolt. My bolts had NO lube on them on disassembly.

 

Larry

 

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I talked to the service manager at my local Dealer and he stated that they now replace all lower bolts if they remove them for any reason.

Amazing!

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I talked to the service manager at my local Dealer and he stated that they now replace all lower bolts if they remove them for any reason.

Amazing!

 

Probably because they come with factory locking compound on them. Cheaper than a lawsuit.

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Or that the bolts bend if not break due to the bad engineering. I have never seen a rear shock bolt on any bike that is that small. Even dual shocks.

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Or that the bolts bend if not break due to the bad engineering. I have never seen a rear shock bolt on any bike that is that small. Even dual shocks.

 

Yes there are hundreds of cases out there splattered all over the forums......not.

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Update.

Heated it up drilled a hole and no the reversible bit did not bite as that was one small surprise. Easy out working nice, then only 1/4" of threads came out. It was broken in 2 places. drilled some more and easy out broke. Swing arm off and heading to machine shop on Monday.

This is a major issue with this design!

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Evening 1812

 

 

 

Sorry to hear of your problems.

 

Easy Out is the most ill named thing man ever invented. They are not correctly named, they should be named "Easily Broke" instead of Easy Out.

 

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One caveat..

 

Although with the clamping pressure released by the end of the bolt falling off it should spin out easily, this bolt is supposed to be installed with Loctite medium strength.

 

HEAT would be your friend, although how to heat it might be a challenge. About all I can think of is after partly drilling the hole, if it doesn't spin out with the reverse drill bit, use a pencil type soldering iron to heat it up - sticking the tip down in the drilled hole long enough that you start smelling some burning smell.

 

Then try the reverse drill bit again, or - an easy-out.

 

This is really an ugly situation. Do you know who torqued it down last time? This really sounds like a rare sort of failure (the bolt torques down on the sleeve on the lower shock mount, and pulls it tight against the inner wall of the swing-arm recess.) I can't imagine it failing unless the bolt was defective, or badly over-torqued (ie - GutAndTight..)

 

Not as rare as you might imagine. As it turns out, my situation is better than the OPs in that my bolt sheared off on both sides allowing me (and my most mechanically capapble friend) to take the shock out before using the Easy Out. The unfortunate part is that I was 400 miles from home. No problem. The bottom of the shock rested on the swing arm all the way home. The only difficulty I had was putting the bike on the center stand to get gas.

 

The take away: It appears that the bushing that goes in the left boss is a "wear item" and will become oblong over time. Replace it when you rebuilt/replace your rear shock including a new red Loctite treated bolt.

 

Click here for my tale of woe.

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OlGeezer, thanks for your link.

It seems it is not so "rare" after all.

 

You do realize that you are talking about two completely different bikes?

His is a 1150RT, while yours is a 1200RT.

They do have some things in common, like:

Boxer engine, two wheels.....

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Same bolt. Same under sizing.

Your are just full of it.

Look, the bike is obviously rubbish, so why not sell it?

I am sure anything else you buy no matter what it is (as long as it's not BMW), will be just sooo much better.

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One issue that bothers me and this is it.

I have owned 40+ motorcycles(6 BMW's) in my life.

I have a little experience with other makes.

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Same bolt. Same under sizing.

Your are just full of it.

Look, the bike is obviously rubbish, so why not sell it?

I am sure anything else you buy no matter what it is (as long as it's not BMW), will be just sooo much better.

For a guy from down under you don't sound like my family there or the fine Bloke's that I have met.

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OlGeezer, thanks for your link.

It seems it is not so "rare" after all.

 

You do realize that you are talking about two completely different bikes?

His is a 1150RT, while yours is a 1200RT.

They do have some things in common, like:

Boxer engine, two wheels.....

 

Same consumable bushing, right?

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Same bolt. Same under sizing.

Your are just full of it.

Look, the bike is obviously rubbish, so why not sell it?

I am sure anything else you buy no matter what it is (as long as it's not BMW), will be just sooo much better.

 

Did I walk into a personal war or something?

 

All I know is that, after owning a 2002 R1150RT, some say the worst model ever made, I have enjoyed (most) of my 10 years of ownership and will replace it with another BMW Boxer. I don't know what other testimonial one may need. Yes, I may be guilty of drinking the koolaid.

:D

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I love the model as I had a 2000 that got me into it.

This bolt is way undersized, or they had a bad batch that they kept selling back to the consumer.

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  • 3 weeks later...

Finally got around to replacing this bolt.......again ;) I used the bolt that 1812 sent to me (Thanks!!) I got the old bolt out after cutting it flush with the swingarm. I had to cut it to remove the shock at the swingarm. I drilled it out using a left hand 1/4" drill bit and then I ran a bottoming tap in to clean up the threads. Seems Ok now, time will tell :thumbsup:

 

I did this work while I replaced the final drive :P

 

One thing that I would like to point out to everyone. Make sure that you push the bushing back into the swingarm before you try to put the lower shock mount back in place. I used a heat gun to warm up the outer swingarm mount and then pressed it in with a c clamp. This bushing is a very tight fit!

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Got my swing arm back from the machine shop...totally scratched up.

Really pissed about this.

Seems I will go over and have a few choice words with the owner.

At least my bike is finally together!:)

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BMW 954 White Aluminum Matte. Available from ColorRite. The ColorRite aerosol can worked very well when I repaired some valve cover damage. If you are repainting the entire swing arm you may want to try any decent aerosol aluminum paint for about a tenth of the cost. The color is really not unique.

 

Larry

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  • 4 months later...

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