Helicoil - Any Tips?

Discussion in 'Shop Talk' started by Lost Kiwi, Jun 23, 2020.



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  1. Lost Kiwi

    Lost Kiwi Member

    Location:
    Was UK, now Mission Viejo!
    Name:
    Simon
    Current Bike:
    Nugget Proflex 657
    Hey guys, the thread has stripped out on my hope brake lever clamp, going to attempt a helicoil repair on it. Got a kit coming and it all looks pretty simple. Drill, tap, insert helicoil, snap of the tang when done and Bobs your aunty......

    Any of you lot got experience of helicoil kits and able to offer any sage words of advice before I start?
     
    herzalot, MolarM and DangerDirtyD like this.
  2. DangerDirtyD

    DangerDirtyD iMTB Addict

    Location:
    CA
    Name:
    Chicken Nugget
    Current Bike:
    2018 Guerrilla Gravity SMASH
    I used one on the threads where the brake caliper adapter attaches to the fork lowers. Keep a clean surface; beware grease or brake fluid contamination.
     
    MolarM and Lost Kiwi like this.
  3. MolarM

    MolarM Member

    Location:
    Orange
    Name:
    Mike Belda
    Current Bike:
    Santa Cruz 5010
    I can’t offer any help. The last time I heard the word helicoil, it was in reference to restoring blown spark plug threads on a VW Bug back in the mid ‘80’s. Might work though, give it a try. What do you have to lose. .......... well on second thought, I’d never risk a procedure where brake failure was a possibility. Get new brakes ASAP
     
    Runs with Scissors and UPSed like this.
  4. siata94

    siata94 Member

    Location:
    lake forest
    Name:
    siata
    Current Bike:
    lazy goat
    If it's the clamp, wouldn't it be easier to tap to the larger sized fastener?
     
  5. Lost Kiwi

    Lost Kiwi Member

    Location:
    Was UK, now Mission Viejo!
    Name:
    Simon
    Current Bike:
    Nugget Proflex 657
    I'm must admit I was in two minds myself @MolarM! If the repair does let go then it shouldn't be the end of the world, the clamp is double bolted so if the coil does pull out then the lever is just going to rotate on the bars. However some googling reveals people have used these with no problems on things seeing much greater forces than I'm capable of generating, so as long as its done to a good standard I now have no reason to think it won't be fine.
    I'd normally err on the side of caution and just replace, but just the postage from the UK to get a replacement is going to cost more than the helicoil kit and I'll be waiting weeks for it to turn up.

    That'd be the easy thing to do absolutely agree! Problem is the bolt head sits into a recess on the clamp side, if I go up a bolt size then that becomes a problem (I sized it all up when I was contemplating what my options might be)
     
  6. Lost Kiwi

    Lost Kiwi Member

    Location:
    Was UK, now Mission Viejo!
    Name:
    Simon
    Current Bike:
    Nugget Proflex 657
    Did you use any loctite or other type compound to help hold it in place @DangerDirtyD ? Some people say it's a bit of added insurance others say nope, don't bother doesn't do anything.....
     
    DangerDirtyD likes this.
  7. siata94

    siata94 Member

    Location:
    lake forest
    Name:
    siata
    Current Bike:
    lazy goat
    not enough metal to enlarge the recess? But it seems you've got it pretty covered, just trying to plant seeds of doubt haha
     
  8. Redman

    Redman Well-Known Member

    Location:
    Cypress, Ca
    Name:
    Kevin
    Current Bike:
    SC OG Hightower 29'r
    I've used them many many times. 90% success rate.

    my only advice... when drilling out AND tapping, make sure the drill and tap are AS SQUARE AND PLUMB TO THE WORK SURFACE AS POSSIBLE. The helicoil will not seat correctly if the hole is tapped at a slight angle to the work surface. TAKE YOUR TIME.

    I've used them on motorcycle engines, motorcycle forks, swingarms, and all kinds of beverage canning equipment in another life.

    Oh yeah, buy the actual Helicoil brand. NOT some cheap knock off.
     
    mtnbikej, Grego, herzalot and 3 others like this.
  9. DangerDirtyD

    DangerDirtyD iMTB Addict

    Location:
    CA
    Name:
    Chicken Nugget
    Current Bike:
    2018 Guerrilla Gravity SMASH
    The screw had some left over on the threads already. I didn’t add any more.
     
    Lost Kiwi likes this.
  10. heyitsdave

    heyitsdave Member

    Location:
    Fullerton
    Name:
    Dave Gilbert
    Current Bike:
    29er single speed
    I use them all the time and even have one installed in the chain tensioner on my single speed. Ends up being better threads than tapped aluminum. Thread locker on the insert is good. Drill and tap straight and get insert started straight and all will be well. You'll probably end up doing the other lever, too so it ends up being equally as awesome!
     
    Grego, DangerDirtyD, herzalot and 2 others like this.
  11. skyungjae

    skyungjae Member

    Location:
    Fullerton, CA
    Name:
    Kyung Jae
    Current Bike:
    2015 Santa Cruz Bronson C
    I've had two Marzocchi 66, and I tried every thread insert to repair the stripped post mounts. All of them would back out if I needed to adjust the caliper. Maybe it was due to them being magnesium, but it's hard for me to trust helicoil or any other option.
     
  12. Lost Kiwi

    Lost Kiwi Member

    Location:
    Was UK, now Mission Viejo!
    Name:
    Simon
    Current Bike:
    Nugget Proflex 657
    Couldn't have been easier! Clamped the lever to a bench to keep it flat, you can see the stripped out threads on the left hand hole.
    IMG_5606.jpg
    Dropped a bolt with a nut on it down the hole as a rudimentary depth gauge to mark up on the drill bit how deep to go, drilling through would have ruined the lever.
    IMG_5607.jpg
    Nice fresh hole drilled out ready for the helicoil. The bolt that was in there was an M5, looking at the size it got drilled out to I reckon it would have been close to M6 so reality is very minimal amount of material is removed from the piece.
    IMG_5608.jpg
    Tap the hole and insert the helicoil. I didn't quite get the whole coil in but easy enough to grind of the remaining that was sticking proud of the lever. Had a bit of a moment when I was trying to get the tool that threads the coil in back out as it was pretty tight but a good yank and it came free. The coils have a tang on the bottom which needs to be snapped off after its been inserted and thats it, your done!
    IMG_5609.jpg
    Installed back on the bike, the new thread feels better than before. Hard to explain but with an old aluminium thread putting bolts in can feel almost coarse and a bit grabby, with the coil in its feels smooth as silk. Like your threading into steel - I'm guessing this is what @heyitsdave was talking about :thumbsup:
    Will be taking the bike out for a test run later this afternoon. Pretty stoked with the result and its certainly saved me a bit of cash.
    Result.jpg
     
    Oaken, heyitsdave, doublewide and 8 others like this.
  13. jimbowho

    jimbowho Member

    Location:
    acton
    Name:
    james jim jimmy
    Current Bike:
    GT sensor 29r
    Scully's tip of the day for people just starting out in the mechanical world. Steel bolts can cop an attitude in aluminum. I often put a light coat of (boat trailer axle grease) on bolt threads. Its blue you can see it easily. Lots of specially made stuff out there for this but one tub of the blue stuff will last 89-years. Tip#2 when a bolt gives a hint of seizing STOP ((DO-NOT)) squirt it with WD-40, and get/find anti seize and gently go back & forth. My Avatar is the look you get if I find out you did not heed.
     
    Runs with Scissors likes this.
  14. da big hills

    da big hills Well-Known Member

    Location:
    pearl harbor
    Name:
    cagey
    Current Bike:
    enduro 29
    Helicoils come in three flavours.
    Since your are in Al Aly there will be a vicious galvanic cell. You should use a cad grease or zinc grease. I am sure you did not get the phosphor bronze MEOW. Go to McMaster-Carr for some Antiseize lubricants with corrosion properties. Al Aly is at the bottom of the galvanic series.
    I used to put them in while under water. Helicoil tap drill and tap. The Helicoil thread is stronger than the parent because the helix is a bigger diameter than the one you lost
    Happy trails
     
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