Porsche 911sc locking platencv joints important?

[Jvdv23]

I have changed the cv joints on the rear axle of my 1980 SC. When tooking the old ones off, I noticed it did not have the locking plates.

Where are these plates for and it is it important?

Thx. Joost

[davewood]

I have just replaced my drive shafts on my 83 cab and the locking plates weren’t there either

[Drbraunsr]

//http://forums.pelicanparts.com/porsche-911-technical-forum/222537-reconstructing-constant-velocity-cv-joints.html[/URL]

See post #12 by Grady Clay (expert - RIP) and you'll have enough facts to determine whether you need the moon plates or not.

[walt]

I think the moon plates act as a lock washer as they aren't allowed to rotate. I've used them and I have also used schnoor washers.

[mepstein]

They are softer metal than the stub axle and let the bolt, dig in a bit.

[RWebb]

Grady was quoted recently as to 3 functions - do a search in the last week to find it

[Walt Fricke]

Just note, when considering how necessary these locking (moon) plates might be, that Porsche both used and didn't use them. As long as the mating surface between CV and flange is dry, and the bolts are torqued (and retorqued) to spec, the joint will not fail.

[RWebb]

or... the joint will not fail often enough to cost more in liability to the manf. than the total costs of making the part, stocking it, distributing it...

[Iciclehead]

I never used them on my 911....just a good set of washers. Main thing to note is all those gaskets compress and will loosen the bolts over the first few miles, so retorque after a bit is the key to the kingdom.

To me, those CV bodies are pretty big and heavy, I can't see what additional load spreading those plates would bring other than preserving the surface of the CV joint.

Dennis

[ClickClickBoom]

Originally Posted by Iciclehead

I never used them on my 911....just a good set of washers. Main thing to note is all those gaskets compress and will loosen the bolts over the first few miles, so retorque after a bit is the key to the kingdom.

To me, those CV bodies are pretty big and heavy, I can't see what additional load spreading those plates would bring other than preserving the surface of the CV joint.

Dennis

What you are describing is settlement, a well understood engineering concept. Reread/read the CV Reconstruction thread. Grady explains what the original factory rationale was, and multiple authors add plenty of solid engineering input.

[Ian Comerford]

I could be wrong but think the moon plates were added when the thickness of the metal casing was reduced significantly as a way of applying a preload and not distorting the metal. Earlier joints had much thicker metal that was not susceptible in this way.

[ClickClickBoom]

Originally Posted by Ian Comerford

I could be wrong but think the moon plates were added when the thickness of the metal casing was reduced significantly as a way of applying a preload and not distorting the metal. Earlier joints had much thicker metal that was not susceptible in this way.

You are wrong.