Hi all, 

 

Being the complete **** that I am when I get impatient, I absolutely fubar'd the last thread on one of my drivers seats fixing point.

 

So the seat is held on by 4xM10 spliced bolts. The last one the head got rounded and I got impatient cause the rain was coming and drilled it out, but destroyed the thread in the process.

 

Anyone got any recommendations for how to securely fit another bolt in there 😂 thanks all

If the thread is still there and you haven’t gone right through then use a plug M10 tap and some locktite and should be grand.

 

if you have drilled right through and the thread is gone and now it is just a clearance hole then you will want an M12 plug tap and appropraite replacement bolt.

Edited 14 June, 20205 yr by BigJase88

Might be an idea to take it to someone less impatient for some help on this one.  Wouldn't normally suggest resorting to non-DIY, but this is quite a significant safety thing.

Is it a rear one, or a front one? Seatbelt plus airbag does the work restraining you in a forwards direction*, but the seat needs to stop you going the other way, so I'd've thought the front fasteners were most critical in that respect.

 

Edit: * but seatbelt clip is attached to seat, so that argument is flawed...

Edited 15 June, 20205 yr by Wino

Another quick point on this topic, as I'm in the midst of refitting a seat myself.  The screwthread on these bolts is M8, not M10, although the head fits an M10 XZN tool. 

 

There is such a thing as an M9 thread, so that's one re-tapping option, but you may be quite limited about what head types you can buy M9 bolts with, and what will fit in the available space. M10 will give more choice, but of course bigger heads again.

11 minutes ago, Wino said:

Another quick point on this topic, as I'm in the midst of refitting a seat myself.  The screwthread on these bolts is M8, not M10, although the head fits an M10 XZN tool. 

 

There is such a thing as an M9 thread, so that's one re-tapping option, but you may be quite limited about what head types you can buy M9 bolts with, and what will fit in the available space. M10 will give more choice, but of course bigger heads again.

Standard bolts are M4, M5, M6, M8, M10, M12, M16

 

M9 would be very specialist and few and far between. I have in example never seen an M9 bolt

 

could do with knowing the pitch as well 1.25, 1.5 etc

Edited 14 June, 20205 yr by BigJase88

The guide pins on FSIII brake calipers are an M9 thread, oddly enough. Came up in a recent thread where someone knackered the thread these go into on the bearing housing, and unfortunately helicoiled  M10 thinking that's what they were.... Even more off-topic, I looked carefully at one of these bearing housings the other day, and those M9 threads look to be part of pressed-in bushes, rather than tapped into the general surroundings. Might suggest they could be pressed out again and replaced, like for like.

 

Another option to maybe explore is cutting back (or removing carefully depending on your love for the car) some carpet in the neighbourhood of these captive nuts, to see how they get in there, and how replaceable they seem.