Why do xzn bolts exist?

[bbob203]

Especially smaller than 8mm.. Stripped every 1 but 2 (6mm) out of both 020's im taking apart. Im replacing them with flat head 12.9 socket cap bolts. I followed all the steps cleaned out the heads with brake clean made sure they were 100% free of oil and debris... So i drilled the heads off.

[CRSMP5]

 

you tapped socket in with hammer too?? if not thats your fail... ive never had the 6mm xzn in 020 give me such fits.. but id use a impact driver if i felt they would strip.. but at min.. tapping the socket in will mushroom the bolt into case and let them release with lots less work...

[bajacalal]

Especially smaller than 8mm.. Stripped every 1 but 2 (6mm) out of both 020's im taking apart. Im replacing them with flat head 12.9 socket cap bolts. I followed all the steps cleaned out the heads with brake clean made sure they were 100% free of oil and debris... So i drilled the heads off.

I think they do it because it expedites assembly at the factory, by allowing further automation of the process- machine grabs the bolt head, the triple square pattern is self-aligning, the bolt is threaded in and torqued to spec, the tty bolt can't be overtorqued as easily, the amount of wrench turning by individual workers is minimized.

But I hate non-standard hardware on all my cars I've owned and I try to replace as much of it as possible, whenever feasible.

[smokeinmirrors]

triple square bolts: I've had 100% extraction success by using the socket in conjunction with vice grips to spread the load.  I definately still replace them with hex heads upon re-assembly.

[bbob203]

Any idea where to get m7x1.25 flat head allen or torx bolts to replace these with.

[Syncroincity]

Any idea where to get m7x1.25 flat head allen or torx bolts to replace these with.

FASTENAL, if you have one near you.

[libbydiesel]

I've never had any issues with XZN bolts provided they are actual OEM bolts and not cheap aftermarket copies.  They're actually less prone to stripping than allen head bolts at the same torque.  I thought the axle bolts were 8mm xzn.  Any chance you're using the wrong size bit?

[CRSMP5]

4 6mm ones behind 5th gear in 020....

i think his socket crap.. i bet i have 4 bbob..

[8v-of-fury]

I thought the axle bolts were 8mm xzn. 

Correct you are.

[burn_your_money]

They're actually less prone to stripping than allen head bolts at the same torque.

Very true. XZN FTW

[theman53]

I personally think a good grade socket head "allen head" as some call them are way better. I replace the CV ones every time I switch the cv joints out for a Socket head.

Fastenal...competition to me, but 9/10 times they will not have it in stock no matter how common it is. If you go to a store and they have it consider it lucky, as I don't even carry M7 stuff, they hardly ever do.

If you go the socket head route go SPS Unbrako or Holochrome for the best results.

[bbob203]

Fastenal has no m7 bolts listed on there site in flat socket cap.

[theman53]

Fastenal has no m7 bolts listed on there site in flat socket cap.

Yep, I said 9/10 and I was being nice.

[bbob203]

Fastenal has no m7 bolts listed on there site in flat socket cap.

Yep, I said 9/10 and I was being nice.

So man can you get me some? m7x1.25x15mm


RE:crsmp5 yes i think part of it was junk xzn bit from advance auto only place i could find an m6 xzn same day.

[bajacalal]

The problem I find with the triple square is that the torque is applied to the points, which works fine when the fastener is new, but when it is corroded or dirty it doesn't make good contact. The axle bolts are hard to tap in securely with a hammer because of their location. An allen bit applies torque to the flats of the hexagon which I think are less likely to strip, especially if the tool is not perfectly seated in the hole.