UK Monster Owners Club Forum » .: Technical :. » Cans, Tyres, Brakes, etc. » 1996 front pinch bolt thread

Reply
 
Thread Tools Display Modes
Old 05-03-2017, 02:56 PM   #1
davkyt
Guest
 
Posts: n/a
1996 front pinch bolt thread

The thread in the suspension foot has come out....
Is there any fix for this other than the obvious?
It's the one on th the right hand side, and the outside bolt. The inside one is fine.
  Reply With Quote
Old 05-03-2017, 03:45 PM   #2
Flip
Registered User
 
Flip's Avatar
 
Join Date: Mar 2010
Location: Beachtown
Bike: M900
Posts: 2,188
What do you mean it 'has come out' ? (insert the obvious joke here).

The fork lower is a tapped thread so unless it was previously heli-coiled and it is the insert that has come out when you've undone the cap head pinch bolt I don't quite see what you mean
__________________
You're perfect, yes, it's true- But without me you're only you!
Flip is offline   Reply With Quote
Old 05-03-2017, 03:59 PM   #3
davkyt
Guest
 
Posts: n/a
The hole where the pinch bolt goes has no thread in it.
About 1\4 of a turn away from the torque wrench "click", the pressure released and the the bolt was allowed to move freely. I took the bolt out..... And the thread from inside the hole is now on the bolt
  Reply With Quote
Old 05-03-2017, 04:00 PM   #4
Darren69
Transmaniacon MOC
 
Darren69's Avatar
 
Join Date: Sep 2013
Location: Sutton In Ashfield
Bike: Multiple Monsters
Posts: 6,022
Do you mean the original aluminium thread has come out with the bolt, eg stripped? I guess some Neanderthal has thought they need to be super tight and overtightened them. They only really need nipping up as they're only designed to stop the axel from turning and undoing.
__________________
Roast Beef Monster!

Termignoni and Bucci - Italian for pipe and slippers!

S4 Fogarty, S4R 07T, 748, Series 1 Mirage
Darren69 is offline   Reply With Quote
Old 05-03-2017, 04:28 PM   #5
Flip
Registered User
 
Flip's Avatar
 
Join Date: Mar 2010
Location: Beachtown
Bike: M900
Posts: 2,188
If the thread that came out was a perfect coil it sounds like it had already been hell-coiled where someone else had previously stripped it.

If that's the case it's a simple job just to clean it up and fit a new heli-cook to repair it.
__________________
You're perfect, yes, it's true- But without me you're only you!
Flip is offline   Reply With Quote
Old 05-03-2017, 04:46 PM   #6
jerry
Old Git
 
jerry's Avatar
 
Join Date: May 2006
Location: Cricklade
Bike: Multiple Monsters
Posts: 2,816
8ft lbs or 10nm is all the torque they need its a 6mm
__________________
MONSTERMAN
jerry is offline   Reply With Quote
Old 05-03-2017, 05:22 PM   #7
davkyt
Guest
 
Posts: n/a
Yes Darren and Flip

There was a perfect coil around the bolt when I took it out

So what do I need to do to fix it?
  Reply With Quote
Old 05-03-2017, 07:50 PM   #8
Luddite
Registered User
 
Luddite's Avatar
 
Join Date: Aug 2011
Location: Southampton
Bike: M1100evo
Posts: 2,465
There's a really helpful step-by-step guide on fitting thread inserts in this month's Practical Sportsbikes magazine. I've sent you the relevant pages via PM. You can ignore the first six steps as the hole has already been tapped for you, although it might be a good idea to run the tap down the hole to ensure the thread is clear.

You'll need a replacement insert and insertion tool. Machine Mart do an M6 kit for £16.79, https://www.machinemart.co.uk/p/040216677/ which should do the job.

Hope that helps.
Luddite is offline   Reply With Quote
Old 05-03-2017, 08:00 PM   #9
davkyt
Guest
 
Posts: n/a
Thanks luddite
  Reply With Quote
Old 05-03-2017, 08:31 PM   #10
utopia
No turn left unstoned
 
utopia's Avatar
 
Join Date: Jun 2010
Location: leicester
Bike: M750
Posts: 4,545
Hold on .. are we certain here that the thread has already been helicoiled before ?
Its quite possible to pull out the entire original aluminium thread with the bolt, and it will look very similar to a helicoil insert.
I'm more inclined to think that this is what has happened.
Either way, I would still start from the beginning of the helicoil process and run the tap down the hole, even if its only to clean up the threads before fitting the insert.
But I strongly suspect that you will have to actually cut the new thread for the helicoil.
There may even be further complications if the clearance diameter of the plain half of the hole is too small to pass the helicoil tap through.
You could of course tap it from the other end but then you significantly increase the chances of the tap not going in square, as it is no longer guided by the plain section.
If it comes to threadcutting, use paraffin as a cutting fluid/lubricant on the tap, cut the chips off small and blow them clear to avoid them jamming in the new threads and ripping them.
Remember, you have one shot to do it right, or else its a new fork bottom.

If I were doing it from scratch I'd strongly consider doing a practice run on a bit of scrap aluminium first.
Either that or find a local garage that will do the work (and take the risk) for you.

When its all done and you're retightening the two bolts, nip them up very gently and gradually, moving repeatedly from one to the other as you gradually approach the clamp torque on the spindle, and remember they only need a very low torque.
Use lube on the bolts, not Loctite .. black moly grease ideally or fine grade copperslip.

Worst case scenario, as a super-bodge you could put a nut on the back.
You could at least ride it to the garage like that.
utopia is offline   Reply With Quote
Old 05-03-2017, 09:08 PM   #11
Luddite
Registered User
 
Luddite's Avatar
 
Join Date: Aug 2011
Location: Southampton
Bike: M1100evo
Posts: 2,465
Just so we can confirm what you're dealing with here, what were you left with when you removed the 'coil' from your bolt? If you can stretch it out and it breaks up, then it's a newly stripped thread. But if it's solid, like a coilbound spring, then it's a helicoil-type insert.

It's fixable either way, it's just one way is easier than the other!
Luddite is offline   Reply With Quote
Old 06-03-2017, 08:57 AM   #12
davkyt
Guest
 
Posts: n/a
It was a coil that broke off in sections. So from was ppl are saying it would most probably be a freshly ruined thread?
  Reply With Quote
Old 06-03-2017, 10:10 AM   #13
Flip
Registered User
 
Flip's Avatar
 
Join Date: Mar 2010
Location: Beachtown
Bike: M900
Posts: 2,188
Okay, get a nice little torch and have a look at where thread 'should' be in the fork leg- if looks neat and 'thread like' you have taken a heli-coil insert out. If it looks knackered then you have stripped the original thread and it will need repairing.
__________________
You're perfect, yes, it's true- But without me you're only you!
Flip is offline   Reply With Quote
Old 06-03-2017, 11:01 AM   #14
Luddite
Registered User
 
Luddite's Avatar
 
Join Date: Aug 2011
Location: Southampton
Bike: M1100evo
Posts: 2,465
It does sound as if you've got a stripped thread there (if you've still got the pieces, check the material. If it's steel, it's an insert; if it's aluminium, it's a stripped thread).

If you do need to drill and tap the hole and want to do it yourself, you'll need a pillar drill or at least a drill stand to ensure accuracy. If you've not got the equipment, you could try a local engineering firm who should be able to do something like this pretty cheaply.

Either way, you're going to have to remove the fork, if you haven't already done so.

As utopia said, for a temporary fix, you could fit a nut (and washer) on the end of the thread, but you'd need a longer bolt to do this.
Luddite is offline   Reply With Quote
Old 06-03-2017, 06:25 PM   #15
davkyt
Guest
 
Posts: n/a
On looking there is about 1cm of thread left.... So a longer bolt might do.

If anyone has a spare, longer bolt to sell me it be awesome.... or direct me to one. I don't want to guess and knacker the remaining thread

I have some spare forks with knacked stanchions... It might be time to try and disassemble them. I don't have a bench vice tho so i might have to pop it to a garage to get the feet off.
  Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 04:03 PM.

vBulletin Skins by vBmode.com. Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.