Captive nut question

[Jmac]

Ok fellas , the captive nut in the chassis rail on my Audi 80 is stripped due to the bolt being pulled through when it was damaged. Now the captive nut is meant to be 10mm metric but is around 12mm with some slop. No more room to go up a size there either. What do you reckon with helicoiling it??? i am shaking my head at it but i know there is differetn grades like inconel and the likes, my thoughts were that helicoils can pull with load. This captive nut is for a subframe bolt. Only other option is to cut the rail open and weld in a new nut and that is ELM St really.
What are your thoughts
CHeers
Jmac

[h100vw]

Helicoil if you have the gear, weld another if you don't.
I reckon its a Westonsuper.... not ELM St
Gavin

[Jmac]

Yeah i can get a helicoil mate but what do you reckon with it being a subframe mounting hole????? its one of 4 mind. To weld it it means cutting the chassis open and welding a nut then stitching it back up. Just a little bit concerned about the tension and strength using a helicoil, but mind you the aerospace industry uses them hey
Yeah a Weston super hahaha you got it mate
Cheers
JMac

[Peter Jones]

The recoil inserts claim to be stronger than the original threads. I use the M8 and M6 coils all the time for thread repairs, never pulled one out yet.

Pete

[Jmac]

Yeah Peter they say that mate, and im liking your confidence . Just got that feeling it being the chassis, but hey im going for it.
Let you know how i go
Cheers for the input
JMac

[roccodingo]

Installed correctly the heli coil will be fine. make sure when your tapping the thread out that you tap it square to the bore.
.

[jdrose]

the heli coil will be fine. they use them to refit head bolts, which have upwards of 40 foot pound of pressure om them. i have had nothing but good experinces with helicoils

[brad]

I've used helicoils for sparkplug holes & head bolts.

When I worked in the aircraft industry the structures guys used ..... /thinks really hard.....

keenserts - apparently they were superior to a helicoil.

but I also recall they used something called a cherry rivet. (but maybe that was to hold in a nut plate)??

Sorry I can't be any more help, I was a Production Planner & just pointed at things & said "Fix that".

[Golf Loon]

I`d open a flap in the chassis rail from above, weld in a new nut and then stitch it back down. If it wasnt a subframe, I`d use a helicoil.

[Preen59]

the heli coil will be fine. they use them to refit head bolts, which have upwards of 40 foot pound of pressure om them. i have had nothing but good experinces with helicoils

Yeah but its all load in one direction.. Helicoils aren't good with axial load.

I'd go keysert or recoil. Hacking the rail open and welding in another captive nut is a big pain in the a-hole.

I've had good experiences with keyserts, aslong as you have the meat around the hole to drill and tap it large enough.