UKC

/ Stripped thread on bike brake lever assmebly

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TMM on 07 Jan 2018
Once more I throw my self on the mercy of the UKC collective when it come to repairs.

I have purchased a second hand Islabike for my soon to be 6 year old, her first bike with gears!.

I was tidy up the bike and replacing the grips. In loosening the brake lever assembly the thread totally stripped on the M6 bolt holding it on the handlebar. I guess it must have been massively over tightened in the past.

I am looking for thread repair items and like the look of Loctite Form-A-Thread. This looks like witch craft but sadly does not seem to be available in the UK or Europe.

The tap and die sets look difficult to use and the helicoil tap in types look difficult as the other side of the clamp which goes around the handlebar will be in the way.

What do people suggest?

I have already sent a message to Islabikes so full replacement is an option.

Heading out now but will reply later, thanks in advance for any smart ideas.
gethin_allen on 07 Jan 2018
In reply to TMM:

Could you post a photo somewhere for us to get a better idea.
On a kids bike the components are unlikely to be very expensive so probably wouldn't cost much more than fixing it, unless you have all the tools and bits knocking around the house already.
Cheese Monkey - on 07 Jan 2018
In reply to TMM:

The clamp? Quick and easy way would be to grind a flat on then use a through bolt with a nut against the new flat
Martin W on 07 Jan 2018
In reply to Cheese Monkey:

Exactly what I was going to suggest.
Dax H - on 07 Jan 2018
In reply to TMM:

As suggested, use a longer bolt with a nut on the back.
A tap will be no good unless there is enough meat to tap it out to M8, the original m6 thread is gone so you have to go bigger.

Something like a helicoil or nutcert needs a bigger hole drilling and again there might not be enough metal to fit one and the helicoil kit will cost more than a new lever for a kids bike.
TMM on 07 Jan 2018
In reply to TMM:

Thank you for the suggestions.

I am looking a fix that is aesthetically pleasing to a six year old so I am hoping that Islabikes come good on replacement.

Has anyone any experience of a liquid/glue/epoxy thread repair solution? I am intrigued, seems too good to be true.

Even if I can get the part I am tempted to see if I can make a helicoil fix drilling out to allow a replacement M6 thread or trying a die cut M8 fix.

PITA. My wife is struggling to understand why it is bugging me so much!

Lee Proctor - on 07 Jan 2018
In reply to TMM:

Cheese Monkey's suggestion is spot on!
TMM on 07 Jan 2018
In reply to Cheese Monkey:

> The clamp? Quick and easy way would be to grind a flat on then use a through bolt with a nut against the new flat

Can you explain further for someone who is ambitious but challenged?

What does 'grind a flat on' mean?
Dax H - on 07 Jan 2018
In reply to TMM:

Never used a thread repair solution but you could clean the hole very very well, fill it with chemical metal and tap a new M6 hole if your that bothered.
ChrisJD on 07 Jan 2018
In reply to TMM:

I've might have one off an Islabike you can have foc (assuming its a flat bar bike).

If you want me to check, message me and send photo of the lever.
Cheese Monkey - on 07 Jan 2018
In reply to TMM:

Sure. Insert a longer bolt than normal so that it goes completely through the clamp and fit a washer and nut on the bit of bolt that sticks through. It ideally needs a flat surface on the clamp for the washer and nut to tighten against so make one with a file or angle grinder

This may all be completely futile depending on the design but most basic ones are like that
artif on 07 Jan 2018
In reply to TMM:

If its the same as the Islabike sat next to me, the through bolt would work, use a button head bolt and put a nut & washer on the under side of the the lever.
Alternatively, using a longer M6 bolt for a thread form, lightly coat the threads of the bolt with grease then spread araldite rapid steel over the bolt and screw it in to the brake-lever as far as possible, clean off the excess and wait for it to set, unscrew and refit the old bolt.
TMM on 07 Jan 2018
In reply to Cheese Monkey:

Hi Cheese,

Ok, that's what I thought you meant.

So I would need to drill through the remaining part of the assembly so that a new, longer bolt protrudes on the other side and is held captive by a washer and nut.

No doubt effective but I am trying to keep an OEM look. This solution would mean the nut and washer would be located on the top of the assembly and would not look so attractive.
TMM on 07 Jan 2018
In reply to artif:

Got it. The button head is a possibility and have the head on the top with nut and washer beneath.

I was considering the araldite idea after looking at Loctite Thread-a-form. Got a horribly feeling I'll f**k it up and end up needing to grind off a glued in bolt!
TMM on 08 Jan 2018
In reply to TMM:

Thanks to everyone for their helpful suggestions and offers of spare parts, very much appreciated.

I have secured a new part from Islabikes for £9.99 which seems very fair.
jkarran - on 08 Jan 2018
In reply to TMM:
Drill the hole through 6mm to clear out the old thread, file/dremmel or counterbore a flat on the back and replace the screw with a longer one and a nylock or dome nut (no sharp edges and neat. Paint to cover file marks.

Alternatively drill and tap it M7. They're rare but available (ebay). Tapping Aluminium is dead easy.

Epoxy won't be strong enough getting a good bond in aluminium is difficult and it's nowhere near as strong as the ali anyway, it'll easily strip out.

A new lever will be comparable with the tools and a new nut/bolt price wise. Personally I'd buy tools over parts every time but it's worth a thought.

edit: note to self, check start and end of thread before replying.
jk
Post edited at 11:24
john morrissey - on 20 Jan 2018
In reply to jkarran:

you will be surprised. Islabikes spares are pretty cheap really.  Give them a call.  post is free too. 


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