The Dreaded Captive Nuts

Subafury · Post by **Subafury** » Sun Oct 21, 2007 11:30 pm

i dont know about you guys over east but here in WA some of the regulars have had some problems with some of the captive nuts welded to the thin chassis rails of our L series.

The captive nuts im talking about are the 3 ones under lift blocks including the gbox crossmember one, and 2 others that all sit atop a plate attached to radius rod.

So far on Alex's, D3V1L's, AndrewT's, and most recently my car - due to lift kit and being driven hard offroad the small welds holding these nuts have torn and the nuts end up almost coming out of the chassis!

Its a little bitch of a problem, but we have so far resolved it by making new captive nuts - nuts welded to small bits of flatbar- and then these are put into the existing holes and mig welded to body. But because of the thin chassis steel holes are burnt through very easily, not to mention hard to get to.
ive got some pics of my repairs that ive done this week(ill put up in a minute). was wondering if anyone else has had the same problem/how they ve fixed it.

(btw this thread is probs in worng section but i was thinking along the lines of lift kit dramas etc.)

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Sun Oct 21, 2007 11:41 pm

Over here basically the same way as you describe. But lately i have been over welding the entire section under the floorpan with 4mm plate seam welded to the body this braces the nuts to a larger section of flooring.

Subafury · Post by **Subafury** » Sun Oct 21, 2007 11:47 pm

Pix of the captive nuts coming out of the car

very hard to get round rusted nut off.

holes where the nuts came through

had to sacrifice a bolt to get it out of the rail.

ill take some more of my repair once i find the camera.atm ive just tacked up the new nuts/plate to the chassis and its waiting on some proper mig welding.

D3V1L · Post by **D3V1L** » Sun Oct 21, 2007 11:57 pm

hahah what about my captive nuts??...at least all your cars where running or will be running after the repairs..my poor car ended up in the crusher,.....so be thankfull :P

dave

AndrewT · Post by **AndrewT** » Sun Oct 21, 2007 11:58 pm

Hey SubyWan got any photos of the more recent repair jobs of yours you've done?

Outback bloke · Post by **Outback bloke** » Mon Oct 22, 2007 5:58 am

It has been covered quite a few times. In my belief the only way to fix it properly is to do it from inside the cabin. Once the bolt is out like in the foto get a long screw driver and drive it right up through your floor.

Now you know exactly where to cut. Cut a U shaped piece about 50mm x 100mm long by 5omm. Fold the section up and over to get it out of the way.

Clean up the area above where the bolt was. Get some thick 4-6mm plate and fit as much of it in there as possible. Make sure you have a hole predrilled for the new bolt to go back through.

Put your kit back in and a longer bolt up through the hole, now put a nut on the new bolt and tighten every thing in to place.

Once it is all fitted and tightened, weld as much of the new plate as you can. Also weld the nut to captivate. Rust proof it all and then fold the floor back over the top. Weld it and then rust proof it.

If you have put a big enough plate in there you will never tear it out again.

AndrewT · Post by **AndrewT** » Mon Oct 22, 2007 11:48 am

That certainly does sound like the best method....are all three of these accessible from the interior? The furthest forward one doesnt look like it is.

Smokey · Post by **Smokey** » Mon Oct 22, 2007 12:19 pm

Nope, the inner front most one, gbox xmember from memory is not accessible through the floor, but it also hold very little weight. Its the two outer ones front and rear that are accessible and more structural.

The one that is not accessible is captivated to a small plate that is tacked to the underside in 3 spots only. I bent that whole area all outer of whack on my L.

Fixed mine by getting a new car to swap all the goodies over to.

BYB, would your method work as a preventive measure? ie could that be done with the existing nut still in place or would it have to be ripped out first and then strengthened. As I would like to look at options to ensure this doesn't happen again?

Smokey · Post by **Smokey** » Mon Oct 22, 2007 12:22 pm

Subafury wrote:So far on Alex's, D3V1L's, AndrewT's, and most recently my car

What style lift blocks are you guys all using? I have heard that more occurrences of this happening to tube style blocks rather than solid alloy?

Mine was tube also...

AndrewT · Post by **AndrewT** » Mon Oct 22, 2007 12:27 pm

Alex's is the hollow block/squash tube type (indentical to Matt's in those photos I beleive).
My BYB kit was missing these blocks when I got it all those years ago (second hand) so I made my own, mine are solid steel cylinders. But I think my captive nut damage was caused by a very severe incident (inattention in the dunes, drove off a small cliff, landed VERY hard).

I wonder if it would help to make these three lift blocks more as a single component to the lift kit, perhaps linked together at the top and bottom with some kind of plate?

YouTube · Post by **El_Freddo** » Mon Oct 22, 2007 12:33 pm

AndrewT wrote:I wonder if it would help to make these three lift blocks more as a single component to the lift kit, perhaps linked together at the top and bottom with some kind of plate?

I've thought about this with the front and rear assemblies being a one or two piece lift block (more like linked blocks). I don't know the logistics of this as i'm yet to get a lift kit in. I'm keen on this mod as i've found rust in one of my lower front chassis rails that will need attention sooner rather than later.

Gread thread by the way.

Cheers

Bennie

AndrewT · Post by **AndrewT** » Mon Oct 22, 2007 12:39 pm

The two lift blocks that are at the same level, my 6" kit actually came with these made as a single piece which mounts diagonally. The third one (the front one) is just a single block. I'm still going to try and link it to the larger piece with some flat bar at and angle some how.
I'm also planning to brace all these blocks with a piece of metal comming forward and bolting to the engine crossmember. That way for them to move towards the back of the car with an impact, they would need to pull the whole engine crossmember with them.
I'm hoping to have the only weak point as the radius rod....much easier to replace!

Smokey · Post by **Smokey** » Mon Oct 22, 2007 12:44 pm

I have often wondered this too and can't see any reason why it would not help to spread the load more evenly over the three captive nuts. However everyone I have ever spoken to has said otherwise, including hardcore 4x4 repair shop etc.

Allied Armament in the USA have their lift kit's3 blocks welded together...

This is their website. Left hand side is the Subaru specific link.

Also worth mentioning is that the original bracket for the radius rod effectively joined these captive nuts together at the body, so why should the blocks not be joined to one another also?

BrennyV · Post by **BrennyV** » Mon Oct 22, 2007 12:48 pm

ahhaha yummm guns and subaru lift kits :P

AndrewT · Post by **AndrewT** » Mon Oct 22, 2007 12:56 pm

yeah you can see how theirs are done in this pic...
http://alliedarmament.homestead.com/Liftkit01.jpg

Thats kindof what I want to do with mine.

Post by **Alex** » Mon Oct 22, 2007 2:42 pm

AndrewT wrote:Alex's is the hollow block/squash tube type (indentical to Matt's in those photos I beleive).

no, i have the solid alloy type.

alex

Subafury · Post by **Subafury** » Mon Oct 22, 2007 2:54 pm

AndrewT wrote:yeah you can see how theirs are done in this pic...
http://alliedarmament.homestead.com/Liftkit01.jpg

Thats kindof what I want to do with mine.

yeh same here i think i will weld all the blocks as one. still thinking of ways to strengthen the other side so it doesnt happen.

found a couple other threads with the same problem- looks like you have spent a lot of effort in repairing these hey Smokey?
see here http://www.ausubaru.com.au/showthread.p ... uts+ripped
and also i see the same problem can happen in the rear!!
http://www.ausubaru.com.au/showthread.p ... uts+ripped
also smokey would u mind puttin a couple pix up- the old links dont work.

to summarise from these threads it seems that the best way to repair is what i have done, except for the rearmost hole which should have a (6mm-ish) plate with new nut welded to it from the inside (ie cut a hole in footwell). the others arent accessible from there.
other ideas floating around in my head is to weld lift blocks as one, then to the engine x member or similar and also weld the blocks to the radius rod plate.

AndrewT · Post by **AndrewT** » Mon Oct 22, 2007 3:25 pm

Alex wrote:no, i have the solid alloy type.

alex

ahaha thats right, it was kindof a half-cast kit, some was hollow steel, some solid alloy. I should remember seeing as I was the one to bolt them in originally! derr..

fredsub · Post by **fredsub** » Mon Oct 22, 2007 4:48 pm

the Subamod kit i had, used a rectangular steel bar for the two diagonals.
The only minus was they didn't do the not crushable section for the bolts like your supposed to (as in the rta literature).
IMHO, I have a problem with the idea of those as 2 separate blocks, because there are angular moments about those bolts whenever in situation of climbing/descending, hitting hard etc etc..

Matatak · Post by **Matatak** » Mon Oct 22, 2007 7:15 pm

i got an idea....

get an MY