DIFFERENCE IN DRIVETRAIN AXLE BOLT

[rich10]

Hi, All. So I've done a outer cv boot replacement. I ordered the kit from Pelican Parts. They forgot to send the replacement bolt...
Old bolt is a hex-bolt. 27mm. Easy-peesy.
Went to the dealer, the replacement bolt and the one sent to me by Pelican is a 12-pt bolt. The new bolt is def not 27mm.
What size is it?
Are these bolts interchangeable? Is the 12-pt an upgraded product? Since the bolts are completely different, do I have to change the bolt on the other side or will it be ok to have the new 12-pt and the hex on the other?
What are the torque specs for the 12-pt bolt bc I know they are different than the hex?
Im really not interested in over-torquing this bolt considering where it is.

 

[high_octane3541]

I've never replaced an axle bolt

 

[eurocars]

I have also never replaced one and I've had my axles out a couple dozen times. There are two different styles but they are interchangeable

 

[rich10]

I've taken this from the Bentley forum.

"There is a lot of confusion regarding the torque specs on the drive axles bolts. Let me clarify with the latest information as I understand it.

There are 3 different axle bolts that were used and are in circulation.

1) A hex head bolt with a seperate washer (27mm head)
2) A 12-point shoulder bolt with ribbing under the head (24mm head)
3) A 12-point shoulder bolt with a smooth contact surface under the head (24mm head)

The hex head bolt is torqued to 200 N*m + 1/2 turn as stated in every source.

The confusion always creeps in regarding the 12 point shoulder bolt. If you have a ribbed version, this massively increases the friction between the shoulder of the bolt and the hub surface and, therefore, the torque to create the same clamping force is reduced significantly.

With a ribbed 12 point shoulder bolt, the torque spec is 70 N*m + 1/4 turn, as has been stated before.

The VAG group came out with a newer version of the 12 point shoulder bolt with a smooth mating surface under the head of the bolt more recently. This version of the 12 point bolt has the same torque specs as the original hex head bolt at 200 N*m + 1/2 turn.

The newer 12 point bolts (Part No. WHT005437) has no ribbing on the mating surface underneath the bolt head.

Remember, these bolts are all torqued into yield, and therefore stretch. Being stretch bolts, they must always be replaced.

Thanks,

John"

I guess I'll check the bottom of the bolt before I torque it to 200nm +180degrees...

 

[donjuan1jr]

The old 6 point bolt is 200nm...

The new 12 pt bolt is not.. don't rember the tq spec as I never use a wrench on those...nor do I ever replace them.

 

[rich10]

Is there a definitive answer on this?
Aren't they stretch bolts?
So many have said they dont even replace them.

 

[donjuan1jr]

They are a stretch bolt, hence the extra turn after torque yield.

I can get a number for u on the 24mm bolt later.

 

[B6 Passat]

 

[707Stang]

^^^ that takes me back

 

[rich10]

So the answer is...
If the 12-pt has a smooth surface on bottom face of the bolt then the torque is the same as the hex.
The tensile strength on both of the bolts on the front of the bolt=8.8 so the torques have to be the same.

 

[ROH ECHT]

Mine has been removed a couple times. I've watched the tech do this to replace the boots twice and for something else. He never replaced the bolt and when tightening the bolt he never torque spec'd it...only tightened the h3ll out of it with his impact. Nothing has come of it done that way to date with 131k miles on it.

If I ever remove the front bolt myself...I would replace the bolt and pull out the torque ratchet though. I did so when I replaced the rear hub bolts and the rear hubs.

 

[donjuan1jr]

I stand corrected...However have noticed the new ones are not ribbed in my parts department...they come with red thread locker on the threads tho. Just looked through my box and found i have a few extras of both...

 

[langer]

Good info. My Raxle came with the new version and I was confused as hell about torque specs initially.