[N_Jay]

So, I am working on replacing the headliner on the Cayman, and found that some asshole (probably the one who fixed it up after it's original accident) used the wrong screw to hold one sun visor in place.

From the head (Philips, not Torx) I knew a) it was the wrong screw, and b) it was forced in!

So now do I:
a) Just use a new screw of the force threaded size.
b) Try to re-tap the threads to the first metic size that holds, and use that.
c) Drill out the 6 pop rivets holding the piece of metal, and tack weld in a new nut of the proper threads, then pop rivet back into place.
d) Other (looking for ideas)

It is not a structural piece. The sun visor mount is a piece of steel pop riveted onto the windshield frame after the body is painted. It is unpainted, possibly galvanized, and held in place with 6 large headed aluminum pop rivets.
(I will probably have to do some searching to find similar pop rivets)
The threads look like they are part of a nut, that I assume is tack welded to the back side, but I don't see any sign of wedding heat marks. (Maybe some kind of spot welding?)

Pictures will follow.

[worf]

... found that some asshole (probably the one who fixed it up ...

Don't get me started on the stupid shit I have seen done to 928s over the last 25 years by both "professional" and DIY owners. I have no conclusive evidence to support that the former group is on average better than the latter.

That rant written...

From the head (Philips, not Torx) I knew a) it was the wrong screw, and b) it was forced in!

So now do I:

The first question I have is: what is the thread of the OE fastener? I assume you can determine this by looking at (all if necessary) another fastener.

If the fastener has a "machine thread" (e.g. M5 x 0.8 or M6 x 1.00 etc.) then my go-to thread repair is a TimeSert. The "kits" are not cheap. But it's arguably the best thread repair "technology." Inserts are available in various lengths for pennies. I've used the 5mm-long variety on occasions on 928s and that length is probably what you're looking at if what I suspect is true, is true.

The threads look like they are part of a nut, that I assume is tack welded to the back side, but I don't see any sign of wedding heat marks. (Maybe some kind of spot welding?)

I have seen this mechanism on the 928 in many places, so it isn't a bad guess.

If there is indeed a square (or whatever) nut welded to the back of the metal bracket then I think it very likely that the original fastener is a machine thread type and thus the TimeSert would be my first choice.

This depends upon how much free space on the back side of the nut is available as you need 5-ish MM of free space behind the insert for the various bits.

a) Just use a new screw of the force threaded size.

Last resort.

b) Try to re-tap the threads to the first metic size that holds, and use that.

Then YOU are "that guy" that "fixed it last time."

I did this once many, many years ago and I regret it to this day.

c) Drill out the 6 pop rivets holding the piece of metal, and tack weld in a new nut of the proper threads, then pop rivet back into place.

TimeSert. If you have zero space behind the nut then you might have to remove the bracket to do the TimeSert.

The main problem I see with welding on a new nut is getting it in exactly the right spot and/or not "killing" the bracket.

(I will probably have to do some searching to find similar pop rivets)

A *wide* variety of pop rivets are available from McMaster-Carr. I, just recently, got a selection of (IIRC) 4.9, 5.0, and 5.1 MM rivets for 928 work.

Apropos rivets, I just bought a Millwaukee M12 (LiON) electric rivet gun and it's the bees knees. Way better than the manual and air-powered ones I used to use.

[N_Jay]

... found that some asshole (probably the one who fixed it up ...

Don't get me started on the stupid shit I have seen done to 928s over the last 25 years by both "professional" and DIY owners. I have no conclusive evidence to support that the former group is on average better than the latter.

That rant written...

From the head (Philips, not Torx) I knew a) it was the wrong screw, and b) it was forced in!

So now do I:

The first question I have is: what is the thread of the OE fastener? I assume you can determine this by looking at (all if necessary) another fastener.

If the fastener has a "machine thread" (e.g. M5 x 0.8 or M6 x 1.00 etc.) then my go-to thread repair is a TimeSert. The "kits" are not cheap. But it's arguably the best thread repair "technology." Inserts are available in various lengths for pennies. I've used the 5mm-long variety on occasions on 928s and that length is probably what you're looking at if what I suspect is true, is true.

The threads look like they are part of a nut, that I assume is tack welded to the back side, but I don't see any sign of wedding heat marks. (Maybe some kind of spot welding?)

I have seen this mechanism on the 928 in many places, so it isn't a bad guess.

If there is indeed a square (or whatever) nut welded to the back of the metal bracket then I think it very likely that the original fastener is a machine thread type and thus the TimeSert would be my first choice.

This depends upon how much free space on the back side of the nut is available as you need 5-ish MM of free space behind the insert for the various bits.

a) Just use a new screw of the force threaded size.

Last resort.

b) Try to re-tap the threads to the first metic size that holds, and use that.

Then YOU are "that guy" that "fixed it last time."

I did this once many, many years ago and I regret it to this day.

c) Drill out the 6 pop rivets holding the piece of metal, and tack weld in a new nut of the proper threads, then pop rivet back into place.

TimeSert. If you have zero space behind the nut then you might have to remove the bracket to do the TimeSert.

The main problem I see with welding on a new nut is getting it in exactly the right spot and/or not "killing" the bracket.

(I will probably have to do some searching to find similar pop rivets)

A *wide* variety of pop rivets are available from McMaster-Carr. I, just recently, got a selection of (IIRC) 4.9, 5.0, and 5.1 MM rivets for 928 work.

Apropos rivets, I just bought a Millwaukee M12 (LiON) electric rivet gun and it's the bees knees. Way better than the manual and air-powered ones I used to use.

Thanks man.
1) Yes a machine thread.
2) Plenty of space behind to do whatever is needed.
3) also like times-sert, but probably overkill for just holding a sun visor mount.
4) Difference is using a Tap to form the new threads instead of the screw itself.
5) The bracket is substantial enough that I am not worried about destroying it (other than discoloration) by tack welding.
6) thought that your times-sert was crazy overkill, till I realized it would save me 6 pop rivets of some odd (I am sure uniquely german) size.

Guessing that the screw is 4mm or 5mm unless there is a common size in between.

Lucky I have a sample of an un-f-ed up on on the drivers side.

And I share your disdain for (so called) mechanics who take stupid shortcuts.

[N_Jay]

Ok, just looked up the m3, m4, and m5 time-sert kits.
$108 each.

Anyone have one a can borrow?

What ever size it is, if I buy it, I will never strip another one of that size!

Anyone ever use "E-Z LOK"? (Duh!, just noticed that they are for wood. )

[worf]

Like I said: the kits aren’t cheap.

You can try rethreading with a tap. Since the clamping force required isn’t much, you don’t need a lot of “good threads.”

It surely doesn’t hurt to try.

Whether it works or not depends, of course, upon exactly what wrong fastener was forced into place.

Rivets from M-C will be cheaper than the shipping and I bet they will have whatever “odd” size is required. I was mildly surprised at how many zillions of sizes they offered in several different materials.

The other really cheap option is Helicoil which you maybe able to find at a good local h/w store. But, I won’t bet that it’ll work in a “nut context.” But, again, won’t hurt to try if a tap doesn’t work and you’re no worse off except for $10-ish.

[worf]

Anyone have one a can borrow?

What size do you need?

[fpena944]

Ok, just looked up the m3, m4, and m5 time-sert kits.
$108 each.

Anyone have one a can borrow?

What ever size it is, if I buy it, I will never strip another one of that size!

Anyone ever use "E-Z LOK"? (Duh!, just noticed that they are for wood. )

I'll ask my dad tomorrow if he has something that can work in his stash.

[N_Jay]

Anyone have one a can borrow?

What size do you need?

M5-0.8

[N_Jay]

Well, Rivets are about $20 shipped for 25, so I might go that way.
I think I have a manual pop rivet tool somewhere.
Will have to practice my welding a bit.
Heck, I could probably use JB-Weld.

First I am going to see if a new M5 screw hold, but betting the threads are buggered way to bad.
Based on the "wrong" size screw was fairly tight and its head was buggered up so someone put some effort screwing it in.

Blue is the hole with the nut behind it. Red are three of the 6 rivets.

image.png

Only on-line picture but no reference for part #1

image.png

[XR4Tim]

Part number is 98755542202 for the passenger's side.

[fpena944]

Well, Rivets are about $20 shipped for 25, so I might go that way.
I think I have a manual pop rivet tool somewhere.
Will have to practice my welding a bit.
Heck, I could probably use JB-Weld.

First I am going to see if a new M5 screw hold, but betting the threads are buggered way to bad.
Based on the "wrong" size screw was fairly tight and its head was buggered up so someone put some effort screwing it in.

Blue is the hole with the nut behind it. Red are three of the 6 rivets.

image.png

Only on-line picture but no reference for part #1
image.png

Dad has the tool you're looking for but not the right size. Sounds like you're figuring out a different solution though.

[N_Jay]

Thanks for checking.

[worf]

I've got M6x1.0, M8x1.25, M10x1.25, M10x1.5 M12.1.5.

No M5 though.

Try the tap. Helicoil, or...

[worf]

Heck, I could probably use JB-Weld.

... I have used JB-weld for thread repair for low-clamping force holes when no other workable alternatives were practical.

My rule in situations like this is: if the proposed fix might work, and if it has no chance of making the problem worse if it doesn't work... then... why not?

Tap, Helicoil, JB-weld...

There are some other thread repair technologies between Helicoil and TimeSert in terms of start-up cost. Might google that...

[N_Jay]

Heck, I could probably use JB-Weld.

... I have used JB-weld for thread repair for low-clamping force holes when no other workable alternatives were practical.

My rule in situations like this is: if the proposed fix might work, and if it has no chance of making the problem worse if it doesn't work... then... why not?

Tap, Helicoil, JB-weld...

There are some other thread repair technologies between Helicoil and TimeSert in terms of start-up cost. Might google that...

Actually we're looking at going the other way using a new nut but JB welding the nut in to place instead of tackwelding.

[worf]

Actually we're looking at going the other way using a new nut but JB welding the nut in to place instead of tackwelding.

You’ll need to make a “mound” of JB-Weld.

How much have you played with that stuff?

[N_Jay]

Actually we're looking at going the other way using a new nut but JB welding the nut in to place instead of tackwelding.

You’ll need to make a “mound” of JB-Weld.

How much have you played with that stuff?

More than I care to admit.
Plan would be a light coat under the nut, a well antiseized bolt nice and tight, and then filet in the six sides of the nut upto and just over the top edge.

[worf]

Plan would be a light coat under the nut, a well antiseized bolt nice and tight, and then filet in the six sides of the nut upto and just over the top edge.

Ok. As long as you realize from experience that JB-Weld doesn’t “like” to be glue.