Bolt drilling advice - Door striker bolts

[markh]

The previous owner has at some point replaced the triple square bolts with Philips head bolts. I'd never really paid attention until I decided to fix a rattly passenger door latch.

Correct bolts have arrived so I set about trying to remove the old bolts and of course the heads round straight away.

So I've got as far as drilling the heads off so I can remove the striker and have started drilling out the bolts but wanted to check:

a) I'm not going to lose the captive nuts (I assume not but would like to be sure!)
b) Do I keep drilling carfeilly through the middle and hope the thread collapses - I have no idea if they've been loctited in (or worse - it's A US car)
c) Other option? Eazy out etc?

[PeterK]

The nuts are on a plate & can’t go far

Try locking 2 nuts on the ‘studs’ & see if they’ll wind out. They may collapse now that you've drilled them, but you've nothing to lose.

Otherwise, yes just drill them out with increasingly bigger drills, maybe use a dentist pick to get the remnants out & finish off by running a tap down the threads

[Gary71]

If you have a welder then filing the centre of those lock nuts Peter mentioned will help to loosen things off as well with the heat that goes down the bolt.

Obviously some penetrating fluid wouldn’t go amiss as well.

Once at this stage I tend to use all the methods at it first time out to maximise chances of success!

[inaglasshouse]

Try locking 2 nuts on the ‘studs’ & see if they’ll wind out. They may collapse now that you've drilled them, but you've nothing to lose.

This plus Loctite on the nuts and an impact gun sometimes works for me. Very satisfying when it does!

[Gary71]

Oh yes, impact gun. Can free off even the most stubborn fixing!

[deano]

Penetrating fluid and let sit... then repeat

Add two nuts if you can thread them on... see if they turn freely

If not, weld nut to the ends to generate heat (obviously, protect your paint) and provide a means to remove/turn the bolts.

[911hillclimber]

Weld a nut is a v good approach.
Do not drill larger than the thread tapping drill diameter, iirc the screws are m8 so no bigger than 6mm drill.
This assumes you start on centre!
The captivating box on the inside of the wing could be well rust too, so slowly does it.

[Nige]

Also you can access the plate from the rear arches. There should be a cover over them to prevent crud ingress, might be worthwhile giving them a blast from the back and you'll also be able to see the state of the plate itself. If it's rusty then it'll probably crumble up if you put too much pressure on winding the knackered screws out.

[Bruce M]

First step is heat. From a blowtorch or (as I use) an electric heat/paint stripper gun.

If they used Loctite, particularly the red variety, it is disabled using heat.

If that doesn’t work, use more heat
Welding a nut on the end add a load of heat and as a bonus gives you something to put a wrench on.

Drilling is a last resort & often doesn’t end well.

[markh]

M8 nuts purchased from the local hardware store today so will update with results...

[markh]

Success!

There wasn't enough thread to lock two nuts and I don't have access to a welder at home so I carefully drilled them out and once I'd got a small bit all the way through switching to a larger one would eventually get them turning and I could then pop them out the back of the wheel well. In the end 3 out of 4 needed drilling.



Ran a tap through the thread to clean up.



Door strikers off, what was left of the plastic removed ready to be replaced and refitted.

[sladey]

Nice one

[911hillclimber]

Very satisfying!