CV Joint, 12-pt bit size for bolts? Options

[dcecc1968]

Can't seem to find a reference for the size of this bit. Thanks for your help.
-Don

[jcd914]

Can't seem to find a reference for the size of this bit. Thanks for your help.
-Don

This is from a VW TDI forum page:

"The triple square, also known as XZN, is a type of screw drive with 12 equally spaced tips, each with a 90 degree angle. Its name derives from overlaying 3 equal squares to form such a pattern with 12 right-angled tips. Common sizes are 6, 8, 10, and 12 mm"

I believe the 914 CVs use the 8mm size bit.

Jim

[mepstein]

My local FLAPS had 4 different size bits for about $8

[injunmort]

triple square size 8

[wndsrfr]

triple square size 8

IMO replace them with 6point allen head and cross drill the heads for safety wire. Somebody here sells them...

[Chi-town]

triple square size 8

IMO replace them with 6point allen head and cross drill the heads for safety wire. Somebody here sells them...

Or cross drill the stock bolts and get the same security and save money?

I'll never understand why everyone swaps out for allen head bolts (IMG:style_emoticons/default/confused24.gif)

[dcecc1968]

Appreciate it fellas!

[jcd914]

triple square size 8

IMO replace them with 6point allen head and cross drill the heads for safety wire. Somebody here sells them...

IMO using 6 point Allen bolts is a mistake. In my experience the allen heads strip much easier than the 12 point triple square bolts. The triple square drive was designed to handle more torque than the older design of the allen heads.

The key to being successful with either style bolt is cleaning the heads of the bolts out so the tool fits all the way in so you have full engagement. Also make sure the threads on the bolt and in the bolt hole are clean when you assemble them. And use a torque wrench to get the correct torque on them.

The safety wire is a very good idea but kind of a PITA to wire them.

Jim

[Olympic 914]

The key to being successful with either style bolt is cleaning the heads of the bolts out so the tool fits all the way in so you have full engagement. Also make sure the threads on the bolt and in the bolt hole are clean when you assemble them. And use a torque wrench to get the correct torque on them.

I have found that after cleaning with a screwdriver or other pointed object, place the tool in and give it a few taps with a small hammer to seat the tool before trying to remove them.

[bdstone914]

triple square size 8

IMO replace them with 6point allen head and cross drill the heads for safety wire. Somebody here sells them...

IMO using 6 point Allen bolts is a mistake. In my experience the allen heads strip much easier than the 12 point triple square bolts. The triple square drive was designed to handle more torque than the older design of the allen heads.

The key to being successful with either style bolt is cleaning the heads of the bolts out so the tool fits all the way in so you have full engagement. Also make sure the threads on the bolt and in the bolt hole are clean when you assemble them. And use a torque wrench to get the correct torque on them.

The safety wire is a very good idea but kind of a PITA to wire them.

Jim

(IMG:style_emoticons/default/agree.gif)

[rick 918-S]

The key to being successful with either style bolt is cleaning the heads of the bolts out so the tool fits all the way in so you have full engagement. Also make sure the threads on the bolt and in the bolt hole are clean when you assemble them. And use a torque wrench to get the correct torque on them.

I have found that after cleaning with a screwdriver or other pointed object, place the tool in and give it a few taps with a small hammer to seat the tool before trying to remove them.

(IMG:style_emoticons/default/agree.gif) and replace the schnor washers. Proper torque is a must. Triple square bolts are harder to strip if the female is clean the the male can fully engage

[ClayPerrine]

(IMG:style_emoticons/default/agree.gif)

If you follow the factory procedure to replace the schnorr washers EVERY TIME you remove the bolts, and properly torque them, you will never have an issue with them backing out. The safety wire is a fix for the problem of "not following the directions".

[cuddy_k]

Triple square bolts are harder to strip if the female is clean the the male can fully engage

Usually the dirtier the female, the easier for the male to engage, but that doesn't apply to cars (IMG:style_emoticons/default/wink.gif)

Since this comes up every so often...

M8 Triple square:

https://www.amazon.com/Capri-Tools-30034-Tr...C125&sr=8-6

Schnoor washers:

https://www.belmetric.com/steel-c-4_39_1020...papv7dfk9do7kh7

[dcecc1968]

Great advice as always fellas!

[Rob-O]

(IMG:style_emoticons/default/agree.gif)

If you follow the factory procedure to replace the schnorr washers EVERY TIME you remove the bolts, and properly torque them, you will never have an issue with them backing out. The safety wire is a fix for the problem of "not following the directions".

(IMG:style_emoticons/default/agree.gif)

Id also add that from my experience most people don’t know what they’re doing when safety wiring.

I have a bag of 100 Schnorr washers. Send me a PM and I’ll throw some in an envelope for you. The ridges of the Schnorr washers lock the bolt in place. But you crush those ridges in the process of torquing the bolt. So, it’s a one time use only washer. Since people don’t follow the directions and change them after each use, they get to a point when the washer won’t hold the bolt and it keeps backing out. So they spend time and money on the safety wire solution. Safety wire isn’t meant to keep the bolt torqued, it’s there to stop a catastrophic failure if the bolt does come loose.

[Tdskip]

As others have suggested you REALLY need to make sure the head is totally snug in the CV bolt, I always tap it fully seated to avoid stripping them.

[Mikey914]

Or start by hand and get 3-4 turns in before going to the wrench.
Yes most folks aren't really good at safety wire, but it will keep the bolt from backing out.

You also do not need to do every bolt you can do every other.

[Rob-O]

Or start by hand and get 3-4 turns in before going to the wrench.
Yes most folks aren't really good at safety wire, but it will keep the bolt from backing out.

You also do not need to do every bolt you can do every other.

Assuming the safety wiring is done correctly. I’d say it’s 50% of the pictures I see if a safety wire job where the wire is done incorrectly, which would allow the bolt to loosen even with the safety wire.

[Valy]

Allen bolts are a mistake.
Use the original bolts, new washer and make sure the surface of the bolts, CV and drive flange are clean and DRY of any oil or grease. Also make sure there is no RTV there as some like to use it there.

The reason those bolts back up is that dirt and grease captured on above mentioned surfaces create temporary pressure that makes you think the bolt is fully torqued. Then the dirt gives up and the bolt torque goes out the window and even the washer doesn't help anymore.