Drilling undertray bolts out

[Mullen]

Edit... nvm.

[Nails]

If they drill them out they'll have to rethread them which will mean they will most probably be one size bigger. Unless they use a helicoil which would be rather expensive for the entire under of the car i think.

not if they do it properly. I had plenty to do after fitting my charge cooler and just centred propely. used a good 5mm drill and the remains of the rusted bolt comes out with the drill or the tap. Replaced with 6mm what I picked up from a local diy place.

[wenguin]

If they drill them out they'll have to rethread them which will mean they will most probably be one size bigger. Unless they use a helicoil which would be rather expensive for the entire under of the car i think.

not if they do it properly. I had plenty to do after fitting my charge cooler and just centred propely. used a good 5mm drill and the remains of the rusted bolt comes out with the drill or the tap. Replaced with 6mm what I picked up from a local diy place.

cheers! i'm grab mostly m6 and a handful of larger ones just in case!

anyone confirm the amazon bolts and washers are the right types?

[cosmos]

Not sure if M7 threads are generally available, that size from memory is for brake parts.
Once the middle of the bolt is drilled out the outer threads see a reduction in tension is the idea hence an easy out.
Build up to 4.5mm hole an use the first taper tap and hopefully cut into the original hole.

Good luck.