Captive nut in sill panel snapped off for trailing arm mount

stilson · Post by **stilson** » Sun Aug 26, 2012 11:59 am

Ham fisted bastard that I am, I snapped one of the captive nuts loose while removing the trailing arm mount on a forrie.

To make matters worse its not my car.

I figure I can hold the head of the bolt with a ring spanner, centre punch and drill the head off - easy part done.

How the hell do I weld a new captive nut in place?

What about those fandangled rivet nut jobs?

Any help much appreciated.

niterida · Post by **niterida** » Sun Aug 26, 2012 12:04 pm

To do it properly you need to cut a hole above the nut, reweld the nut and then replace and weld the bit you cut out

stilson · Post by **stilson** » Sun Aug 26, 2012 1:17 pm

That sounds tedious,

So I should drill up through the hole where the nut should be, then that hole should be centre for the holesaw coming down from the passenger compartment?

B00sting · Post by **B00sting** » Sun Aug 26, 2012 2:52 pm

This happened to us recently when we did the c r o s s b r e d lift kit on my brumby.
godamn nut broke off in the chassis rail. bought a hole saw, drilled out a hole above the nute (so coming in horizontally). reached in got nut out, welded new nut in through hole we cut. temporarily fitted firewall rubber plug then welded up hole that was cut out. pain in the ass.

RSR 555 · Post by **RSR 555** » Sun Aug 26, 2012 9:37 pm

This happened to Guyph when he was removing the trailing arms from a SF Foz. Remove the head like you said and then cut a section (cut 3 sides and fold back the piece) on top of where the nut is (under the back seat) then reweld a new nut in place, then weld back up the cut section and make sure you use plenty of anti-sieze on the new bolts.

stilson · Post by **stilson** » Sun Aug 26, 2012 9:58 pm

Thanks for the input guys, I think I'll have to be as well lubricated as the new bolts will be.....

Sounds like a Friday night job.

taza · Post by **taza** » Sun Aug 26, 2012 10:29 pm

Great, can't wait to do this.... It's my Foz in question

B00sting · Post by **B00sting** » Mon Aug 27, 2012 11:52 am

taza wrote:Great, can't wait to do this.... It's my Foz in question

it's not actually that bad so long as you have someone who can weld

guyph_01 · Post by **guyph_01** » Mon Aug 27, 2012 4:27 pm

lol, this is what happens when you play in the mud... But yeah, What Paul said..

d_generate · Post by **d_generate** » Tue Aug 28, 2012 6:42 pm

Happened 3 times on the WRX, the trailing arm one was easy, just tilt the seat up, take the plastic step off and flip the carpet out the way, work out exactly where the bolt is and drill down with a hole saw that will let a socket get down there to hold the new bolt in place (BlueTac in socket.), we never bothered to weld any of the holes and it's held up fine, one behind the computer, one on the rear cross member and the trailing arm one, I think Subaru didn't expect these to be unbolted so often and a lot and rattle guns kill them which is why they have a tendency to fall off.

stilson · Post by **stilson** » Tue Aug 28, 2012 8:27 pm

Winner, I don't take much convincing.

How does that sound Taza?

taza · Post by **taza** » Tue Aug 28, 2012 9:04 pm

Sounds sweet to me!

d_generate · Post by **d_generate** » Fri Aug 31, 2012 12:08 am

You guys fix it and what method did you use?

stilson · Post by **stilson** » Fri Aug 31, 2012 1:16 am

Not yet.

I'm ready when you are Tarran.

stilson · Post by **stilson** » Tue Sep 04, 2012 7:59 pm

Sorted! Just hole sawed above and held the nut with a socket.

Vacuumed out the swarf and just have to put a bit of paint on the bare steel.

Glad to have it out of the way.

I think Taza has some pics if anyone is interested.

d_generate · Post by **d_generate** » Wed Sep 05, 2012 4:05 am

Sweet, pretty easy really isn't it? Worst one for me was the rear sub frame one as it's double skinned in there but the hardest to work out the position was the front gearbag X member as it was awkward to measure but I pretty much nailed it first shot, just have to follow the spot welds (some idiot had wound the thread out of the nut with a rattle gun as it was still there but the bolt would just spin, luckily there was room to place another nut on top and tighten it from inside because the box rattled like a pig on bumps and it had to go over the pits)

RSR 555 · Post by **RSR 555** » Wed Sep 05, 2012 11:42 am

So you're just leaving the hole there?? not filling it in? I guess it will save on weight

taza · Post by **taza** » Wed Sep 05, 2012 12:05 pm

RSR 555 wrote:So you're just leaving the hole there?? not filling it in? I guess it will save on weight

3 holes actually. I'm just going to put rubber plugs in, atleast then they can be easily accessed for next time

Wasn't too bad of a job, but I was pretty much over it half way through and considering it was 11pm at night

All good now though

stilson · Post by **stilson** » Wed Sep 05, 2012 3:37 pm

I've only got an arc or oxy. I think I'd do more damage than good.

d_generate · Post by **d_generate** » Wed Sep 05, 2012 5:03 pm

Yeah unless you make a massive hole it's a bit hard to re-weld the nut back in place, I left them off for convenience and luckily I did as I've had to get to each one at least once after I thought I'd finished with them, you could put a plate over them I guess but I really don't see the point.......can't see the rails bending without a massive hit that's going to do a heap of damage no matter what.