Propshaft bearing securing bolts – sheared

[Trev16v]

When removing the propshaft from the G60 Syncro, two of the bolts that secure the propshaft bearings into the transmission tunnel sheared. I tried to address one of them today and unfortunately I somewhat cocked it up, having drilled into the bolt stub far too off-centre such that I’ll have damaged some of the captive nut’s thread, and so trying to extract with an extraction tool is going to be hopeless (I did try, but didn’t want to force it any harder).

I think I’m probably going to end up drilling out the spot welds for the brackets from the inside of the car so that I can replace the captive nuts neatly on the bench, and then TIG the brackets back in again after.

Or, could those captive nuts have enough meat to accept being re-tapped to whatever the next size is – say, M9? (Current size is M8, 1.25 pitch thread.)

I did also wonder if the brackets with the captive nuts that are spot welded to the tunnel have a separate part number and could be ordered, but could not find them on ETKA.

Cheers,

Trev

[Chris S]

The captive nuts are classed as part of the bodyshell & are not listed seperately in ETKA,

The nuts should be able to stand tapping out to 9mm, try it & see you have nothing to lose by trying!

also depending on how damaged the thread is? you may find that new M8 bolts will fit tight enough in the old threads, and even better if you loctite them.

[Trev16v]

Thanks Chris. I did try to drill and re-tap, but I didn’t do a very good job.

I’ve put some new weld-in nuts. I’m going to drill the spot welds out and remove those two affected brackets, repair them on the bench, and then TIG them back in I think.

[86 Syncro]

It still baffles me as to why VW decided to use captive nuts for so many applications on these cars, as opposed to simply making a threaded bracket that welds to the body…

You will hear of this problem alot from people changing the front lower control arms as well, as it seems that the captive nuts are only held in place with a couple of spot welds…

[Trev16v]

With the shell rotated on the jig, the option I chose in the end was to just cut out the old captive nuts that had the sheared threads, and weld in new little plates with new nuts welded into place. I did try to drill out the old studs first and rescue the existing nuts, but I made a mess of that.

After welding in the new pieces with the new nuts, I tapped through again just to remove any distortion from heat.

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