Heli Coil & other thread repair options.

[mackayvx Advanced Member Find all posts View Profile Close mackayvx]

Gday all.

Well I am looking to hear some feedback and personal opinions on thread repair kits.

The thread I am looking to repair is a captive nut in the chassis which I bolt my heavy AMTS bash plates too.

When I bought the car this particular captive nut had a siezed bolt in it which snapped when I was removing it.
To remove the broken bolt I had to drill the bolt and use an ezy out.
The problem was the drill wandered and slightly chewed one side of the thread out and I have been babying it ever since.

Well last night re fitting my bash plates she finally let go and the bolt kept spinning.

I am betting my left testicle that there are many other PPers that have the same problem.

So in my days of being a Toolmaker, Heli Coils were commonly used for repairing bad threads but I am wondering...

What thread repair kits have you guys successfully used???

Cheers Drew.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

I am not sure a Heli coil would be your best bet. Can you drill and tap for a larger bolt? Otherwise a nutsert might be an option.

Cheers Andrew

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

I agree, don't think a helicoil will be strong enough for that.
I was thinking the same, oversize.
Perhaps go up to a 10mm thread?

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

I can't remember what it looks like off the top of my head. Is it a nut welded to the chassis or a nutsert? You can helicoil the former but if it is a little off centre now you will need to be careful drilling it out. Going oversize is an option. If it already is a nutsert or rivnut punch it out and redo the nutsert.

[mackayvx Advanced Member Find all posts View Profile Close mackayvx]

Yes, I realise Heli coils are not really suited to this application, but I'm also out of touch with other newer options.

I actually didn't even consider drill and tapping to M10...
I'm wondering if there is enough wall thickness on the existing captive nut to accommodate M10.

So AJ, ... Nutsert eh? ... I'd better Google it.

[mackayvx Advanced Member Find all posts View Profile Close mackayvx]

I can't remember what it looks like off the top of my head. Is it a nut welded to the chassis or a nutsert? You can helicoil the former but if it is a little off centre now you will need to be careful drilling it out. Going oversize is an option. If it already is a nutsert or rivnut punch it out and redo the nutsert.

I actually haven't had a real good look at it...
I just thought it was a 'captive nut'.
But obviously nut's ain't nut's lol!

Nutsert...Rivnut... Peanut...

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Don't even need to google it, type nutsert into the PP search same thing as a rivnut.

Cheers Andrew

[Guest Close Guest]

They're usually nuts welded from the inside of the chassis. There's usually some meat available but not sure if it is enough to go up to M10. Maybe weld a plate to cover up the hole and install a nutsert into the plate where the hole is.

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

Those bolts are m8.
So m10 is only 1mm on the outside.
You should be right, let us know.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

The nuts would be projection welded. I was thinking more like going to 5/16 rather than a 10mm, it's just a bees dick bigger than 8mm so you never know. If you go to the trouble of getting out the welder, just weld up the existing thread, drill and re tap!

Cheers Andrew

[mackayvx Advanced Member Find all posts View Profile Close mackayvx]

They're usually nuts welded from the inside of the chassis. There's usually some meat available but not sure if it is enough to go up to M10. Maybe weld a plate to cover up the hole and install a nutsert into the plate where the hole is.

Now that's a good idea!

I just watched a nutsert install video on YouTube and I recognized them straight away... There are nutserts on the bashplates!!

Andrew my first thought would be to drill the captive nut out with the correct diameter for the nutsert.
The nutsert outer diameter may be large enough to get rid of that captive nut all together.
This well may make the nutsert grab on clean chassis.

I bet an install gun/tool would cost a few pennies!

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

A bees dick is about right, only problem with that, if it works, then you have a bolt that's easy to mix up with the others. Better have one that's obviously a bit bigger so not to mix em up & keep the Toyota metric :-)
Weld it up & drill & tap is ideal. But so is changing them all to M10.

[mackayvx Advanced Member Find all posts View Profile Close mackayvx]

Those bolts are m8.
So m10 is only 1mm on the outside.
You should be right, let us know.

Yes drilling a tapping would be the first option, ie - easiest option.

The nuts would be projection welded. I was thinking more like going to 5/16 rather than a 10mm, it's just a bees dick bigger than 8mm so you never know. If you go to the trouble of getting out the welder, just weld up the existing thread, drill and re tap!

Cheers Andrew

I could try 5/16 I guess but I'd say there wouldn't be much thread for the bolt to grab on.

As for welding the nut up... My little stick welder and my skills are not up to that job!

[mackayvx Advanced Member Find all posts View Profile Close mackayvx]

A bees dick is about right, only problem with that, if it works, then you have a bolt that's easy to mix up with the others. Better have one that's obviously a bit bigger so not to mix em up & keep the Toyota metric :-)
Weld it up & drill & tap is ideal. But so is changing them all to M10.

I don't want to mess around too much with the other bolts as they are OK, plus I'd have to modify the bash plate slotted holes to take 10mm plus clearance.

I'll do it to suit this one bolt and see how it goes.

You know something. 10mm bolts on 30kg of bashplates doesn't sound like a bad idea really.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

You're a toolmaker or ex toolmaker so you can judge if there is enough meat to take the thread out to M10. That is the simplest and easiest option. Actually as a toolmaker you could go M9!

I bought a cheapie (not that cheap) rivnut tool, die bolts and rivnuts and it is great. My battery box set up is full of them. I have also put a heap in a mates car and van. Even so I would just drill and tap the existing weld nuts assuming there is enough metal to work with.