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spherical and in the plural. Just heard a crack as I was tightening the top disc brake nut. Metal came out on the bolt. helicoil job? Which set? Not sure I have longer bolt.. help!
Helicoil , did this to my Yaris and got a local engineer to do them for £20. Strong as ever.
Take out some of the washers? Assuming there's a big stack of them.
I think..... a longer bolt has fixed it. Not sure, will test tomorrow, I don’t dare do it very tight
How much longer is the bolt? That's how much good thread you have. To get full strength from the threads you'll typically need 2D of thread engagement (so if a M6 bolt, you want 12 mm of thread engagement).
Unless the new bolt is much longer, it's Helicoil time.
I can't see any reason not to helicoil in this situation. It will be stronger than the original thread.
1. Obviously, a Helicoil is the long-term fix.
2. If it were me and I wanted an emergency fix, I would get a long bolt (or piece of threaded shaft) and cut the head off, then screw it as far in as I could so that it's engaging all the remaining threads. Then fit the brakes and use a nut to hold it all together. Then cut the bolt down to length.
The reason being for not helicoiling is that I am in rural Sweden, not sure where I can get it done. Is it something I can do myself?
Yeah, you can buy a kit. Don't think it's particularly cheap but it's not too difficult, especially if you've tapped a thread before.
ok will take a look on eBay! its m6 is it?
M6x1.0
You can get an M6 kit on ebay for less than £10, you will need a drill and some basic mechanical skills.
I would suggest measuring and putting tape on the drill bit to mark the depth. Make sure the drill is held straight. Take your time and break the chips when tapping.
Watch a couple of youtube videos first, the kit comes with a few inserts, so you could always practice on something else first.
Its not hard, but it is easy to screw it up.
always practice on something else first.
This.
Do you have (access to) a pillar-drill? And some sort of vice to hold the fork steady? If so, go for it.
hi again, the temporary solution of a longer bolt and threadlock was temporary. I had to remove the brake to bleed them and the threads are not happy.
What kit do ineed from ebay or amazon? there are loads on there! is it M6 bolt replacing with m6 helicoil?
Many thanks
You need a helicoil kit which consists of inserts and a tap and an installation tool IME you do NOT need to redrill and you are better off not doing so - the tap will cut away the required metal as its soft alloy
Tap into the stripped hole to cut a new slightly bigger thread then the insert is fitted. A long insert is needed for post mount brakes
You can then just reuse your existing bolt as you now have a fresh M6 thread
Helicoils are available from Biltema as well, https://www.biltema.se/bil---mc/bilverktyg/bromsverktyg/gangverktyg/gangreparationssats-2000022403
Never used those or any other helicoil stuff.
cheers, many thanks. my nearest biltema is a 3 hour drive away! there are some places online however
https://verktygsboden.se/gaenginsatser/gaenginsatslada-m6-10-25-st
this is correct yes? m6 x 1.0
Helicoil or any generic equivalent eBay special is your friend. Make sure you drill straight and not too deep, those are the critical steps in my experience. Applied a bunch of them on landy transfer cases and blocs and can confirm they not only work but end up being stronger than the original thread.
Pro tip: fork lowers castings are a crappy material to thread something on, specially something that needs to be periodically reinstalled like the brake caliper. Stepped brake adapters that use 2 pairs of screws are the best for this reason
this is correct yes? m6 x 1.0
Yes.
Consider using a 'Timesert' from Wurth:
Similar system to helicoil, but solid insert. No personnel experience but I hate helicoils - plenty of experience with them and they work fine on a fit and forget application, but I've never found them great on items that need frequent removal (the coil occasional comes out comes out).
Wurth are everywhere in Europe.
Cheaper to genuine helicoil is available from Cromwell/Zoro. They may trade under a different name in other parts of Europe.
spoke to a friend who used to work for Öhlins. they have a helicoil m6 x 1 and a pellarbor (pillar drill) at his engineering firm so he is going to help me out for the price of a 6 pack , which here in sweden is ironically more than a cheap helicoil kit off ebay 🙂
could you not just threadlock the helicoil itself with red loctite or something? funny how mixed the guidance is, some say it'll be stronger, others weaker, some say drill other not. it's a minefield!
thanks again
I think the mixed advice reflects the issue with helicoiling, namely that there are a lot of variables. Done properly, it can be very strong, especially if not removed too often. As noted though, if you are constantly removing the bolt it does come with some risk of the insert pulling out. I'd say let your friend have a go. If he worked for Ohlins he ought to be a pretty good engineer! And at the end of the day, what have you got to lose. In general, I don't need to remove my calipers more than once or twice a year anyway.
Whenever I have to remove a bolt from a piece of machinery that my mate has tightened, I know I will usually need the 3 foot breaker bar - he calls it a 'farmers nip' - and they are not good on mtb,s!!😂
If it were me, I would helicoil it and Loctite a stud in there, then use an nut (like the ones used for rim brake pads) to hold the caliper in place. This will prevent any further damage to the forks.
appreciated, thanks
could you not just threadlock the helicoil itself with red loctite or something?
The helicoil is a spring and (theoretically) the thread lock will seep through onto the thread section of the helicoil. Not sure, but I think this is the big advantage of the Timesert since it is a solid insert.
If it was me I wouldn't drill it out in fork lowers, I did the brake hose bolt on some RS last week and although I didn't helicoil I just tapped to 4mm instead of 3mm and stuck in a 4mm bolt instead of a 3mm. The tap cut through the soft Mg alloy by itself... I did slightly clean it 1st with a 3mm bit but didn't drill to the correct diameter for steel threads.
I've done similar on cranks for Jnr... instead of drilling the recommended size for 9/16ths I've used a 13mm with a bit more clearance. The taps are designed for steel so they cut through no issues leaving a bit more material.
I helicoiled some old lyrics using a kit, was easy to do and held fine.
I always use as long bolts as possible now.