Author Topic: HOW TO: Repair rear spinning/threaded wishbone bolt  (Read 24555 times)

Offline rubjonny

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There are several ways to fix this, the first way is to drill a hole through the top of the captive nut and re-tap it, then use a longer bolt.  Though this will only work if the captive nut hasnt broken away obviously! Before you all cry out what a massive bodge this is, its actually detailed in the official VW ElsaWin electronic repair manual.  Here is the printout detailing the repair in full:

If the captive nut has broken away but the threads are ok, you can pop out a panel in the footwell and tap a socket over the captive nut, then tighten it that way. Or remove it entirely and drop in a proper nut. (see pics below for the plate I'm on about) Either way this means you need 2 sets of hands to refit the wishbone/subframe, but its less scary than chopping and welding :grin:

Last way is to cut a hole in the footwell and weld in a new nut, the VAG part number is:
N 904 333 01 - welded nut, M12x1.5 - 2.55+VAT

Here is a nice guide on the process, I didnt write it though! The original was written by ewang3 :)

Quote from: ewang3
A few weeks ago I gave the suspension on my Mk2 valver a major overhaul. Polybushes, Eibach springs etc etc..

All was well until it started creaking like a mo fo. So knowing that polybushes do create a bit more noise than standard bushes for the third time I checked all the torque settings and the bushes. I found that the rear wishbone bolt (the one with the big round bush that bolts into the chassis leg directly under the floor) was spinning in it's captive nut making it impossible to tighten.. bottom!

It didn't feel like it was threaded, it felt like the captive nut had broken loose from it's tack welds and was just spinning with the bolt. Did a few searches on here and vortex and realised that it's quite a common fault.. not being able to find some good images on the fix I took a few on the weekend..

Access plugs in the floor are by no means big enough
to get at the bolt..

So I cleaned up the floor and made 2 cuts..

..with a 1mm plasma cut disc..

Heat the metal a bit with a blow torch and bend it back..

The bolt isn't actually a bolt, it's more of a dommed press fit flange thing.. and yes it was spinning with the bolt. The chassis is caked in wax so it needs scraping off before welding..

Weld the mother in place.. (a bit tricky)

Tighten the bolt NOW just incase the welds don't hold. Once your happy it's holding firm spray the whole area with fresh wax, bend the floor back into place and tack it back down..

Seam seal the welds, and replace the plugs with more seam sealer. Then paint the exposed metal with zink rich paint to stop any rust..

Replace all the underlay and carpet.. job done!

Took about 3 hours.. may take longer if the bolt is threaded as it'll need replacing.
« Last Edit: 12 June 2009, 08:02 by rubjonny »
Hello my name is John and I'm a dub addict.