Rear subframe captive nut spinning
 

I am replacing the rear upper arms on my 2001 conn se, and the job was going well until torquing up the inner bolt on the subframe. Got to about 60lbf and then "crack" and the captive nut started spinning.

Feeling with my fingers over the top of the subframe and there appears to be a cavity where i can feel the end of the bolt.

If i take the subframe off can the captive nut be replaced with a normal nut, and bolt it in with the subframe off the car?

Once done will it then fit back in with the arms fitted?

Because it is spinning i cant now remove it either.

Does anyone have a subframe off the car that they could take a picture of the captive nut arrangement for me? Is it a proper nut welded in? Or one of those square ones. I was just wondering if a suitably sized cranked spanner would fit in the gap to hold it.

On a positive note, removing the subframe will give me chance to do a proper job of repainting it and protecting it, but it all depends if it is possible to get it back in the car with the arms on

No pics sorry, but the nut is just a cylinder with a flat plate where it welds to the subframe, you might be able to get hold of it with mole grips, but its much easier to remove the subframe, you can replace with a nylock nut once you have removed the damn thing!

Pics below showing the welded slots which hold the subframe nuts, stupid idea :shrug: try getting a chisel into the hole and giving the slots a good bang in hope they will loch onto the nut ? Arctic

Now that is a stupid design. Even if they retained the slots you would have thought they could have used a hexagon nut for just such occassions as this. There is just room to get a short stubby spanner in if it was hexagonal. To make it round is a kind of booby trap for mechanics.

From feel i would say its probably the slots that have come off. In the photo there they dont look especially strong, and even when new I wouldnt have given them much chance of holding 89 lbf's.

If you've a MIG with a narrow head you can put a good sized spot weld to secure the captive nut without removing the subframe through the drain hole adjacent to the captive nut ;)

You have to be accurate though as you don't want to weld the bolt to it, tricky as you have to sight it then weld it blind, certainly not for the faint hearted ;)

Have done this in the past saves having to drop the entire subframe ;)

Russ

No MIG, my thoughts at this moment are to try dropping the subframe down sufficiently to improve access to the top of it, then get some grips on the round nut so i can try and undo the bolt again, then remove the round nut and replace it with a hexagon one that i can get a spanner on from the top.

Worst case if i cant get it done that way then remove the lot. From the looks of the subframe bolts and washers i need to get some new ones ready for the task.

Look on the bright side David it's a better design than the Freelander rear subframe captive nuts. :getmecoat:

They are in a closed box section beneath the rear floor, so to get to them if they break away you have to cut through the floor. :eek:

https://i.imgur.com/foPD4OH.jpg

That looks terrible. Not even an access hole above it. The factory must have had great faith in their welding skills.

I must be honest and say that i had expected sub frame removal to be a heavy and difficult job, and i had visions of the securing bolts shearing off leaving me with a bigger problem, but in the end it was easier than i thought. If i were to do the arms again then i would do it this way from the outset.

My time served 6 sided impact socket had become worn so started slipping, but took delivery of a new sealey wall drive impact socket and they all came out nicely.

Good to see you managed it David.
Sorry I was not any help. :bowdown:

Pictures will follow in the next few days. It is all off the car and on newspapers on the dining room table being painted.

All looks good, and nearly ready to go back.