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Rear Bumper bolts rusted/sheared off...
Posted: 11 Feb 2015, 14:06
by sternal
Afternoon...
I tried to remove my rear bumper at the weekend and one of the nuts broke off the other is so rusty it will need to be grinded off...
Once I've taken the bumper off the question is how to reattach ? The broken bolts I'm guessing will have to be drilled out and then is it spot weld new nuts in place and bobs your uncle ?
what bolts/nut size would I need ?
Is the correct way ?
Re: Rear Bumper bolts rusted/sheared off...
Posted: 11 Feb 2015, 15:59
by Woodyyellow
Not quite sure of the size of these bolts - probably 8mm but will check - if you drill the old bolt out very carefully, centring the drill, you should be able to reuse the existing captive nuts. Use a smaller drill first 3mm or so then enlarge upto 6.5mm, the remains of the old bolt will then be able to be removed, allowing you to rebolt the bumper on.

Re: Rear Bumper bolts rusted/sheared off...
Posted: 11 Feb 2015, 16:27
by Ralf85
Useful drilling tip that!

Re: Rear Bumper bolts rusted/sheared off...
Posted: 11 Feb 2015, 17:55
by itchyfeet
Yes M8
Re: Rear Bumper bolts rusted/sheared off...
Posted: 11 Feb 2015, 20:58
by Robsey
Yes it is an M8 bolt.
If the nut is still useable and attached to the van..
The core diameter is 6.8mm IF you are 100% spot on central when drilling.
But 6.5 is more than good enough.
At worst you might need to peel out the remnants of the thread with a scriber or a fine tipped tool such as an awl.
Be careful as the remnants will be sharp.
Then when done, clean out the thread with a M8 x 1.25mm tap.
If welding on a new nut, loosely fit up the bumper using a new bolt and a mild steel plain nut.
Obviously the nut will be held captive in the correct position, whilst you tack weld it to the van skin.
It goes without saying that you can only weld to clean metal.
Re: Rear Bumper bolts rusted/sheared off...
Posted: 11 Feb 2015, 21:28
by sternal
wow !
thanks guys for the useful help a job set out for me in a few weeks time.
just had a look on VW heritage and they suggest M10 ?
also what length 25mm ?
