Every problem gets worse than the last.

[AudiSport]

A person could bolt the old pump back on and use it as a jig. But last time I did it the engine was out…

[Tom]

A person could bolt the old pump back on and use it as a jig. But last time I did it the engine was out…

Yes, although the bolt holes are bigger than the bit so you'd still want to use a drill bushing in the hole. McMaster sells them is endless sizes, so I'm guessing you could find one that would work well.

[Richey]

I give up. I tried a few more things and none of them worked. I have a friend that's going to print the jig for me.

What insert am I looking for at McMaster?

So sorry to hear that. Such a bummer. If I had the power, I would outlaw screw extractors. More often than not they seem to snap off and just make the problem 10 times worse. But we might have a solution for you here on carpokes! Get yourself a cobalt drill bit and watch this video.

[AudiSport]

A person could bolt the old pump back on and use it as a jig. But last time I did it the engine was out…

Yes, although the bolt holes are bigger than the bit so you'd still want to use a drill bushing in the hole. McMaster sells them is endless sizes, so I'm guessing you could find one that would work well.

The drilled hole has to be bigger anyway for a time sert

[Tom]

I give up. I tried a few more things and none of them worked. I have a friend that's going to print the jig for me.

What insert am I looking for at McMaster?

It depends on how you plan to repair the threads. You want the inside diameter to match the size of the drill bit you plan to use. I'm a believer in good old fashion heli-coils for things like this. They are stronger than the original threads, remove minimal material, are available everywhere, and allow for a second chance with a time-sert if something goes wrong. For an M6 heli-coil, you would use a 1/4" or 6.3mm drill bit (tungsten carbide if you can find it). For a 1/4" or 6.3mm drill bit, use McMaster 8492A141 (7/16" OD, 1/4" ID, 3/4" high). I'd get several to help ensure the jig is perfectly centered over the hole -- or otherwise be very careful to line it up perfectly. If you would prefer to time-sert it, or want to try a smaller reverse bit in hopes of backing out the stud, you'd want to pick a drill bushing with an inside diameter to match the bit.

If your friend can print in nylon-cf (or other very hard plastic), you can probably get away with printing the drill bushings using the free downloads that McMaster offers for these parts. Cheaper, with a chance for a weekend repair, though I've never tested it that way. You can download the drill bushing in STEP format from McMaster, which a lot of printers can use without any conversion (such as my Bambu printers). If nothing else, they'd be cheaper than the steel ones for purposes of registering the jig over the hole (with the steel one used for the drilled hole itself). Whether you order the steel ones or print them, you might want to JB weld the drill-hole bushing into the jig. Printers vary in dimensional accuracy, so if your jig is not 'just so' the insert can spin. Not the end of the world, but one less variable to worry about if you JB weld it in place. I'd also use a bit collar, like shown in the video, or electrical tape in a pinch, so you don't drill too deep and into whatever is behind the hole. Good luck, we're rooting for you.

step-bushin.jpg (115.28 KiB) Viewed 601 times

insert.jpg (67.29 KiB) Viewed 601 times

[AudiSport]

Time serts come in regular and “big-sert” if you have an enlarged hole from a failed helicoil or failed previous time sert..

I had to do a big sert on a head stud that had a failed reg sert due to improper install length by someone else to hold the appropriate torque

[Tom]

Time serts come in regular and “big-sert” if you have an enlarged hole from a failed helicoil or failed previous time sert..

I had to do a big sert on a head stud that had a failed reg sert due to improper install length by someone else to hold the appropriate torque

I'm old and stuck in my ways. I'd use Time-Serts for head studs for sure. For the water pump stud, it kind of feels like bringing Cristal Champagne to a tailgate party. But I suppose that's kind of the Porsche way...

[AudiSport]

Time serts come in regular and “big-sert” if you have an enlarged hole from a failed helicoil or failed previous time sert..

I had to do a big sert on a head stud that had a failed reg sert due to improper install length by someone else to hold the appropriate torque

I'm old and stuck in my ways. I'd use Time-Serts for head studs for sure. For the water pump stud, it kind of feels like bringing Cristal Champagne to a tailgate party. But I suppose that's kind of the Porsche way...

I like the steel sleeve with a steel bolt so you don’t have that galvanic corrosion

[dr bob]

I'll add that I often use an indexing punch through the drill bushing first. That puts a dimple dead center in the end of the bolt. Deep enough to functionally flatten any angle on the fractured bolt end.

Removing the extractor sort of obviates this option though. Too tough to dimple very much if at all. It's careful work with a manual punch and a small hammer to get a center dimple and also flatten the end so the drill won't walk around.

---

I'm not sure I'd ever put thread-locker on these bolts. There's just no practical way to get sufficient heat through the bolt and the water pump housing to soften it for removal, as that large aluminum mass behind it will transfer a pretty impressive amount of heat. I generally use only new steel bolts, split lock-washers, a thin film of anti-seize, and an appropriate torque driver at six lbs/ft. I try and clean all the bolt holes with a thread chaser, followed sometimes with a bottoming tap, some air then brake cleaner then air again to clear any debris. Glasses/eye protection of course.

[Richey]

This is what I'm thinking. I measured one of the studs and it's showing the threads are about 12mm deep. I'm guessing the stud bottoms out so that's likely my depth. I've got a choice of 9mm and 12mm as a close match. I don't know that 12mm would go in flush so I think the 9mm would provide enough thread and just let the stud hang out the back of the insert.


https://www.mcmaster.com/products/threa ... size~m6-2/

I give up. I tried a few more things and none of them worked. I have a friend that's going to print the jig for me.

What insert am I looking for at McMaster?

It depends on how you plan to repair the threads. You want the inside diameter to match the size of the drill bit you plan to use. I'm a believer in good old fashion heli-coils for things like this. They are stronger than the original threads, remove minimal material, are available everywhere, and allow for a second chance with a time-sert if something goes wrong. For an M6 heli-coil, you would use a 1/4" or 6.3mm drill bit (tungsten carbide if you can find it). For a 1/4" or 6.3mm drill bit, use McMaster 8492A141 (7/16" OD, 1/4" ID, 3/4" high). I'd get several to help ensure the jig is perfectly centered over the hole -- or otherwise be very careful to line it up perfectly. If you would prefer to time-sert it, or want to try a smaller reverse bit in hopes of backing out the stud, you'd want to pick a drill bushing with an inside diameter to match the bit.

If your friend can print in nylon-cf (or other very hard plastic), you can probably get away with printing the drill bushings using the free downloads that McMaster offers for these parts. Cheaper, with a chance for a weekend repair, though I've never tested it that way. You can download the drill bushing in STEP format from McMaster, which a lot of printers can use without any conversion (such as my Bambu printers). If nothing else, they'd be cheaper than the steel ones for purposes of registering the jig over the hole (with the steel one used for the drilled hole itself). Whether you order the steel ones or print them, you might want to JB weld the drill-hole bushing into the jig. Printers vary in dimensional accuracy, so if your jig is not 'just so' the insert can spin. Not the end of the world, but one less variable to worry about if you JB weld it in place. I'd also use a bit collar, like shown in the video, or electrical tape in a pinch, so you don't drill too deep and into whatever is behind the hole. Good luck, we're rooting for you.



step-bushin.jpg



insert.jpg