I was just tinkering round the bike in the safety of the garage, going over bolts and screws, doing the almost-weekly torquing and tightening and checking of various components, since I ride near-daily, when I discovered the left hand side rear frame to gearbox Allen-head bolt was corroded and appeared to be slightly loose, so I grabbed my 3/8" socket spanner and gave it a quick but light tighten, or so I thought. Snap! The bloody thing broke clean off at the level of the aluminium housing. I've got a selection of hardened drills and 'easy outs' out and am in the process of carefully drilling a small hole in the centre of the offending bolt without buggering the aluminium housing or the threads. I ain't going so well. The hole I'm drilling continues to walk to one side.



I have retreated to re-evaluate the battle ground, binoculars held to eyes I am viewing the bloody tragedy from the safety of the nearest hill. Sometimes it's best to just walk away for a spell, have a smoke, lick your wounds. It's not a gentlemen's war.

TBW,
Turn a small bush and drill it with the drill you intend to use,then fit it in the frame hole. this will act as a guide and keep it central.
If still in difficulty you can open the hole to the core size of the thread and get it out with a scriber.
That is what I have done in the past.
Good luck....and not so much swearing please.
Ajays

ouch ...good luck twb

i have in the past got bit of brass and banged it in the hole that you have created....(given that you have got some way in ). cut the new metal off flat ....then using a verry sharp small guage drill ,, redrill the centre line ....then progressivly build up the size of the drill till you get to the size that you need .....

getting a brass drift and hammering the bolt that has broken ...often helps release the thread from the aluminium lockup, for use if you get an easyout in there
good luck mate

I have a selection of hard bushes which might fit the 11mm hole in the frame (but no lathe to turn one with tho') and will give both these suggestions a go. Ta for the quick responses.

Tomorrow is gunna be a beaut day, much cooler than it's been lately and no rain in the forecast, so a ride was planned, as I don't have to work till Monday. I was really looking forward to going for a scoot over the hills and far away. Cheers, mates.

Two Wheels Better wrote:I have a selection of hard bushes which might fit the 11mm hole in the frame (but no lathe to turn one with tho') and will give both these suggestions a go. Ta for the quick responses.

Tomorrow is gunna be a beaut day, much cooler than it's been lately and no rain in the forecast, so a ride was planned, as I don't have to work till Monday. I was really looking forward to going for a scoot over the hills and far away. Cheers, mates.

yeah its been bliss twb ......nice temp change .....crikey i was looking for a light blanket last night .......mmmm lovin it ....

have fun ...i hope you get your ride in

Yeah, coolish here last night along the bottom edge of the Gold Coast, and I too whacked an extra blankie on. But I fear our mates in the Northern climes will have a chuckle at our version of 'coolish'...20 degrees centigrade ain't quite frosty.

Before the drill went walkabout I had attempted to start off in drill bit increments, and had centre punched the bugger, but she went awry anyway. I located a few brass 11mm spacers which thread into the frame and will give the drill bits new purchase. Tomorrow morning I'm back at it, cuppa in hand.

For now it's a bit of news on the tele about the devastating Christchurch quake. My thoughts go out to those who have suffered there. Internationally, the Libyan crisis is overshadowing the natural destruction of a beautiful city. This old world never rests and more often than not "God's tiny creatures are going crazy on the ground."

TWB,
I believe you will need to use a drill with a hard tip as these Allen screws get a hard skin where they snap, when past this a good high tensile drill will do.
20C is about the 70F...you know how to get at we that suffer.

Our hearts go out to Christchurch folk I can assure you. Our firemen are out there to help and NZ to us is more important than the Phsyco arab. We were also concerned with the floods and fires in OZ.
Let us know how you get on....preparation....not brute force.
Ajays.

I always use left handed drill bits for this type of job, not been lucky enough for the bolt to undo yet but one day.....

Very frustrating when this occurs, it happened to me recently the day before a major planned ride, top RH bolt in the triple clamp snapped off the very same way. These things are very difficult to recover, mainly due to the hardness (grade 10.9) in most cases, and the fact that the break is never a flat surface, so keeping a drill centred is difficult.
The walking away tactic is a good one TWB, as it can save even more unrecoverable damage due to a quick reaction like attacking the problem in haste.
My suggestion - if the gearbox is a good one and you wish to keep it, remove the gearbox complete, drain the oil, then take it to a machine shop with a milling machine and ask them to remove the broken off bolt with a slot drill (8.5 mm is tapping size for M10). You may need to pay for the slot drill, being that diameter. This is a main structural connection as you know, so the job needs to be done properly for you to have confidence.
This socket-head cap screw failure sounds like fatigue related, so, as I did with the triple clamp episode, replace all the connection bolts at this time, using anti-sieze compound during installation. Unbrako are a good quality fastener, I don't recommend S/S in this application, as you know. Dennis

5am Thursday, the sun just barely risen above the treeline, the neighbourhood asleep, none aware of the tremendous forces about to be unleashed, or with such savagery of precision. A few clouds dotted the horizon, another mostly fine, sunny day. Few knew that morning the battle would be so decisive. A surprise attack, well-thought out, well-planned, with reinforcement from the allies coming from far and wide. The enemy never knew what hit them, and not a soul was lost that day. To the victor go the spoils. The sole enemy deserves a proper burial, in the bin. The targeted objective has been reached and there's peace in our time.

"Come get your cuppa before it's cold, darl!"

When I began to read your post, I thought that it was the battle of Austerliz.
You may want to consider changing your nickname for Napoleon!
It's always a pleasure to read your posts.
Good job, and enjoy today's ride.

I've given the area a thorough cleaning, blown out any debris, bits of aluminium, slivers of steel, etc., then chased the threads with a clean, 10mmx1.5 tap. For now a hexhead 10x35mm bolt of sufficient grade is torqued in and holding fast. I've been for a ride. She's good and tight. When the bolt shop opens down the road I'm off to explore their stock. No stainless steel bolts but lotsa anti-seize are going on the threads. The other side's been checked and this one had gobs of A/S on it.

No threads were harmed in the making of this thriller!


Which Frenchy are you here, CF?! Though Napoleon was no doubt a master tactician, I fear he also suffered a sort of megalomania. Nuh, I'm the poor bastard bloke holding up the broken axle.


Thanks for all of your support and the good advice. The roads are dry and the sun is shining.

yay good result ,,,,cheers

I just had a 75km ride down the motorway and through some twisties and all's right with my world. I noticed that the left frame tube was a coupla mm's away from the gearbox and required a slight flex inwards so I slipped a thick flat washer in there as a shim when I replaced both of the bolts (with high tensile strength zinc-plated Allen heads). It might be a tad smoother at highway rpm's around the footpegs now. It's still a beaut day, the sun's shining, only a few clouds, no rain in sight, and a light breeze keeps everything chill. A perfect Summer arvo in paradise. Now I'm going for a real ride. Cheers.

Top job well done.

BIG D

Well done TWB, how exactly did you do it in the end.
Regards,
K-BIKE

It was rather easy, though time-consuming. I moved slowly and deliberately, taking my time and making sure things were aligned correctly. It was early in the AM and I hadn't had a cuppa yet. the neighbourhood was asleep. I was imagining removing the gearbox at times - another chance to re-lube the splines!

I used a threaded brass coupling with a fine hole in the centre. It was approximately 11mm and so it lightly threaded into the frame opening. It allowed me to centre the drill bits and I increased the bit sizes in steps and used a high speed drill until a suitably-sized 'easy out' could fit. A few taps with the hammer and the easy out had bitten into the broken bolt sufficiently to allow it to turn out. I stuck with my trusty 3/8" ratchet on the easy out for torque and ease of handling. At first the busted bolt's threads stopped against the frame lug but since there's a fair bit of flex there I propped the frame away from the gearbox's aluminium housing with a large flat blade just enough to allow the broken bolt to back out 10mm or so.

I used my fingers on the easy out to turn it once it had moved a full turn out. A thorough cleaning of the internal threads with solvent and then air removed any chips of metal. Then I chased the threads with a 10x1.5 tap until it stopped lightly. Another cleaning, a few good dabs of silver anti-seize, and the new zinc-plated Allen heads went in like new, shimmed with a thick flat washer between frame and gearbox on the left hand side only, to take up the slack that naturally occurred there. I rode yesterday and today all day...no worries at all. Problem solved.

Thanks for the step by step explanation, someone is bound to need it one day.
Regards,
K-BIKE