cv joint bolt torque.

[Sydcad]

well I replaced both cv joints (axles) in a caddy 2008 model and the passenger side bolts came loose. What I've managed to find out is it is not common nor uncommon...it happens sometimes. I am looking for the torque settings in NMs and have seen differing values given of 44nm and 70nm. Does anyone have the correct value for these m10 bolts. cheers in advance.

[ECUMotorsport]

The correct torque for the M10 Joint CV Bolt is 80Nm.

[Sydcad]

yeh cheers I saw that somewhere. After further investigation it turns out these are M8 and apparently the torque spec is 40nm for a new bolt. Sounds about right for that size and with a bit of locktite threadlocker they might stay in this time. If anyone with a service manual torque spec can confirm it would be highly appreciated.

[C Chis]

Assuming your referring to item 12... for a 2004-2010 van

12 - Multi-point socket head bolt

Always renew after removing

Specified torque according to version (there are 3 different drive shafts depending on model):

Specified torque M8 x 48 → 40 Nm
Specified torque M10 x 23 → 70 Nm
Specified torque M10 x 52 → 70 Nm




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[Sydcad]

thanks C Chris that is much appreciated. They are the 12 point torx type not the hex head which apparently is a different torque again. So 40 it is then. Cheers.

[Sydcad]

while on the subject of bolts, these things don’t look like anything special. The six bolts that came loose on the drive side of the transmission were stripped of their thread so obviously not high tensile. So what are they and has anybody substituted another bolt that wasn’t marketed as a CV Joint bolt? A bolts a bolt right?

[Doc]

You say the removed bolts were obviously not high tensile but in my opinion (and experience) if the bolts are not properly tightened they will be worked loose in such a way as to destroy the threads.
The force on these bolts is sheer so high tensile to me is maybe not suitable or necessary. I can't picture a situation where these inner CV bolts will experience and tensile force other than that of tightening to the output flange cup.

[Crazy7ony]

If it's bolt number 12 on the pic then when I worked at audi these should always be replaced when removed and also number 11 the plate washer also replaced. The bolts were also torque to nm plus and angle afterwards. I've never had them come loose following this as per workshop manual. Hope helps

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[Sydcad]

I agree it is when the bolts are not properly tightened they will unwind but the thorough stripping of the thread surprised me considering these bolts are supposedly a high strength/high tensile bolt according to the property class they belong to. I guess the tensile strength refers to the bolts breaking point only, not the threads. They were supplied with the new CV axles but are not of the same property class they were replacing. The originals are 12.9 and the substitutes are 8.8. Obviously the lower the property class, the lower the tensile strength and subsequent torque setting.
I imagine also the most tension they would be subjected to is the initial torque when installed but considering they would also be prone to other detrimental factors including heating, cooling and vibration, working in a constant velocity environment, I would have thought a high tensile bolt would be a prudent choice.


the difference in torque requirements between 8.8 and 12.9 is substantial. It's a mystery to me how they can both be right for a CV joint application.
note: the following is just an example of a general usage and not specific to a CV joint environment.

[Scoobysrt]

I was under the impression 8.8 are normal steel bolts just heated and quenched, not high tensile.

[Sydcad]

it's debatable if the terms 'high tensile' and 'high strength' are exclusive or interchangeable and if there is a difference.