Half shaft torque spec

[Mark]

Just changed GV boot...what a pian!!

How many ft/lb of torque to tighten each of the 6 bolts and inside and outside when connecting the half shaft to the ZF and the wheel?

Thanx
Mark

 

[Tim Kay]

Mark, I've always used 74 ft lbs on my 930 cvs

 

[DaveM]

Most importantly red loctite all the bolts. Otherwise they vibrate loose regardless of torque.

 

[Seymour Snerd]

Most importantly red loctite all the bolts. Otherwise they vibrate loose regardless of torque.

There are several methods for this; others include putting the bolts in meticulously dry and using schnorr washers (what the Porsche factory does, I believe), safety wiring them, and using Stage-8 locking bolts (Imports Locking Turbo Bolt Kits | Locking Bolts).

There is a lot of discussion about this on the Pelican Parts and Rennlist forums, since it's a constant issue in the Porsche community.

Also, BTW and FWIW and ICYDN one side of mine uses 12-point socket head screws known as "triple-square". These are not compatible with torx or any other six or 12-point bit, and at the torque levels involved you can strip them with the wrong bit.

 

[Seymour Snerd]

There is a lot of discussion about this...

Here's good but long thread on this subject, post 11 in particular.

http://forums.pelicanparts.com/pors...-constant-velocity-cv-joints.html#post1922501

 

[Cliff Beer]

Having had CV axle bolts come loose before...even with the right amount of torque (I use 75 ft/lbs) and locktite blue, I now use wire locked CV bolts. McMaster Carr sells a nice assortment of 12.9s of different lengths with drilled bolt heads.

I was driving home one night after work many many years ago and boom! No go. Looking under the car (porsche 944 turbo) one CV axle was completely undone....conveniently only about a block from a hardware store. There I was in a business suit crawling under the car sticking CV axle bolts back into the CV...I swore I would never have that happen again!

 

[Seymour Snerd]

....using Stage-8 locking bolts (Imports Locking Turbo Bolt Kits | Locking Bolts).

You may notice that Stage-8 does not list the M10-1.25 thread needed for one side of our driveshafts. However, when asked they supplied me with a set for the same sort of price.

Cliff -- The only wire-lockable fasteners I'm seeing on McMaster are inch, not metric. Are you sure that's where you got them?

I found them in 1.5 thread here http://www.fastenersavings.com/socket-cap-screws-crossdr-pl-110745.html but no 1.25 mm.

IAE you can always drill them yourself (what fun): https://www.pegasusautoracing.com/productdetails2.asp?utm_expid=10520551-6&RecID=9718&utm_referrer=https%3A%2F%2Fwww.google.com%2Furl%3Fsa%3Dt%26rct%3Dj%26q%3D%26esrc%3Ds%26frm%3D1%26source%3Dweb%26cd%3D2%26ved%3D0CEEQFjAB%26url%3Dhttps%253A%252F%252Fwww.pegasusautoracing.com%252Fproductdetails.asp%253FRecID%253D9718%26ei%3D2ZDgUJHbEKLhiAKk-IDIBA%26usg%3DAFQjCNHnQfBxBMNZnq1Maj55oik6noJLsw%26sig2%3DzH8AiVggYI7SzCia_iilYA%26bvm%3Dbv.1355534169%2Cd.cGE or https://www.pegasusautoracing.com/p...usautoracing.com/group.asp?GroupID=SAFETYWIRE


If you're interested in the Schnorr lockwasher method, Mcmaster does not list them as such (Schnorr is a brand name and they make a lot of different kinds of washers). McMaster lists them as "serrated belleville spring" lock washers, for example catalog number 96445K251.

 

[Mark]

As it turns out, replacing CV boot was a pain only because I could not get half shaft removed.

Having removed the 12 inside/outside bolts, the inside end of the half shaft came right off the ZF. However, I must have done a pretty good job sealing the outside end of the half shaft to the carrier with gray rtv.

Am sure outside CV will go at sometine just looking at it, any ideas on how best to break the seal between the outside half shaft and the carrier?

 

[Seymour Snerd]

any ideas on how best to break the [grey silicone] seal between the outside half shaft and the carrier?

Spec sheet says it's good for 450 degrees F. continuous so I don't think heat's going to help. Next thing I can think of is a good sharp chisel... :cry: and then cleaning up any hopefully-small deformation with a file afterwards. Maybe dribbling gasket remover would help, but I doubt it.

BTW (thinking about what to do after you get those joints apart) some people don't seal the mating surfaces at all, instead making sure they are very flat and smooth (sand paper on a glass plate, etc.), and maybe wrapping tape around the outside to control whatever lube makes it through the joint. You want the mating surfaces very flat anyway since the torque resistance is provided by the friction between the steel surfaces anyway, not by the fasteners themselves. Having nothing between those surfaces helps assure that after the fasteners are torqued the clamping pressure does not decrease due to any kind of compression. Apparently after '84 Porsche quit using seals and instead put a cap that covered the outside of the joint.