Reconstructing Constant Velocity (CV) Joints

[rcecale]

Originally posted by Grady Clay
Randy,

Confirm a few things for me:

1) What is the Type Number of your transmission? 915/72 or 915/73?

The tranny is a 915/73.

2) Was there was an end cap on the inboard CV joint that didn’t come loose?[/QUOTE]

Yes. The end-cap on the axle that did not come loose is still intact. (See pic below) The axle that disconnected lost it's end-cap. To get it home, I connected it back, without the end cap. There is now a spray of grease I need to clean up underneath the car.

3) Was there no gasket between the CV joint and the transmission flange? Is it a flat surface without a step for the gasket?[/QUOTE]

There is/was no gasket between the CV joint and the flange on the passenger side. The driver's side is/was presumably the same.



4) What is the length of the “cheese head” bolt (socket head cap screw)? That dimension is measured from under the head of the bolt to the end of the threaded end.[/QUOTE]

The shank is right at 50mm. (Not 52mm)

5) Does the bolt diameter measures nominal 10 mm?[/QUOTE]

The unthreaded part of the shank is 10mm in diameter.

Thanks, Grady!

Randy

[Jack Olsen]

Note: I changed the title of the thread.

[rcecale]

Thanks Jack!

Randy

[Joeaksa]

Excellent thread. Everyday I learn something its a good day!

JoeA

[Grady Clay]

Randy,

Here is a diagram of the ’86 parts:

IMAGE: Axle86Carrera01
"
"
(C) Dr. Ing. h.c. F. Porsche A.G.

The big issue here is the mid-year change that left out the
previously used CV joint gasket #13 (930.332.297.00) and
replaces it with an end-cap cover #19 (928.332.267.01). When
this change was made it was necessary to also change the stub
axle #3 (from 930.332.232.00 to 930.332.232.04) in order to
eliminate the step that received the gasket. On the axle
assemblies (911.332.024.14) that use the friction-welded outer
CV joint there wasn’t any change at the outboard end. The CV
flange at the transmission also changed (from 930.332.209.03 to
930.332.209.05) in order to eliminate the step that received the
gasket. These changes occurred with the change from
G15.69/70 (transmission 915/69 or 915/70) to G15.72/73
(transmission 915/72 or 915/73).

From what I can tell, your ’86 has the later configuration.

It appears you could use the repair sets #18 (928.332.924.02)
for the inboard ends of the axles. I don’t think you can use
repair sets #11 (923.332.037.00) because it fits the 100 mm CV
joints. Use #18 for the outboard ends and slide the parts down
the axle shaft while the inboard CV is removed. You end up with
two extra #19 end-caps.

You should disassemble and carefully inspect the CV joint that
came loose. Keep all the parts in their same original position. It
is possible that the parts (particularly the cage) were damaged
as the axle flailed about. If damaged, you will need a new CV
joint #5 (930.332.034.00). All the CV joints will benefit from
careful cleaning and new molly grease. I notice the quantity of
grease specified changed from 90 g to 100 g in ’87 with no other
changes to the late ’86 axle assembly.

Note: if the boot #10 and the joint flange #9 aren’t in place, it is
possible to get enough angle on the CV joint for the balls to pop
out and the joint disassemble. It may be possible to get
sufficient angle even with the boot and flange in place.

You should carefully clean the internal splines in the hub (#1)
with a brass wire “tooth brush.” You should similarly clean the
external splines and threads on the stub axle. Coat everything
with WD-40. Just prior to assembling the axle into the hub,
make sure the contact surfaces on the inboard end of the hub
and outboard end of the stub axle are perfectly clean. Don’t
drag any dirt or grit in there as you put the axle assembly in the
hub.


One thing I haven’t figured out is the CV bolt specified for use
with the gasket is M10x60 (900.067.118.01) and the bolt
specified for use with the end cap is M10x50 (900.067.123.01).
That is a big difference! Is this a typo in PET? Is there
something that different in the stub axles and transmission
flanges? The critical issue is when all is said and done that the
bolt penetrates the flange sufficiently.

Note that PET doesn’t specify a Schnorr washer. Be sure and use
them anyway. Remember, the raised ID goes under the head of
the bolt.

Best,
Grady

[rcecale]

Thanks Grady!

To coin a phrase VaSteve has used in the past...You, sir, are the Bomb-digity-om!!!!

Heading to a wedding this evening. Printing this info so I can read it and absorb while I'm there. Formal gatherings and me are pretty much like water and oil!

Randy

[Grady Clay]

Experiment:
Was 32K .jpg in above post.
Trying 800x919 = 114K .jpg (about as large as Pelican will accept).
Original image "Axle86Carrera01" is 1507x1731 = 7.46M .bmp
"
"
(C) Dr. Ing. h.c. F. Porsche A.G.

Best,
Grady

[randywebb]

you want a helper for that big nut - don't let the socket get tilted...

And - Grady - what is the function of the cover 928.xxx? I've always wondered if I should add it to my older CV setup.

[Grady Clay]

Randy,

I think there are several reasons:

First I think Lobro marketed it to Porsche as “Everyone else is using it – MB, Audi, VW, BMW.” I first saw end-caps on the CVs on a McLaren CanAm car in the late ‘60s or early ‘70s.

Second, it is easier to assemble during the manufacturing of the car. No juggling of the gasket while trying to get six bolts started.

Third is probably the contamination of the bolt threads with CV grease. I can’t imagine PAG being able to assemble the earlier axles and keep the bolt threads and clamped surfaces free from moly grease.

I’ll bet the end-cap provides a better grease seal than the gasket. Porsche has gone to great lengths to reduce the “leaks oil & grease” image. No one likes to pull in with their $80K++ and everyone downwind scatters. I think there are some German federal regulations on leakage of anything.

In 09/84 Porsche published the reason as:
“The CV joints of drive shafts for 6 and 8 cylinder engines have been standardized.
“The CV joint diameter of 911 Carrera has been changed from 100 to 108 mm (as already for 928 S/911 Turbo and 911 Carrera Turbo Look). Change does not apply to early U.S. production. An end cap is pressed on for CV joint sealing. The formerly applied seal is omitted. The recess required for this flat seal in the CV joint flange (transmission end) and drive shaft (wheel end) is also omitted.”

Part of my research next week is to see if Lobro put some sealant between the pressed on tin pieces and the CV joint.

Yes, if I were specifying a 911, it would use the 930.332.037.04 drive shaft (axle assembly) that has the end caps, the 930.332.232.04 stub axle, the 930.332.209.05 CV flange at the transmission, the (moon) plates) 911.332.191.00, M10 Schnorr lock washers, and slightly longer M10x52 than standard 900.067.123.01 M10x50 12.9 CV bolts (cheese-head screws).

Best,
Grady

[rcecale]

Unfortunately I wasn't able to do anything with my car yesterday. Home improvement chores got in the way again.

Checking out the e-mail I received from our host, it looks as though the parts I ordered Friday are on the way. I'll call today and see about making changes anyway. Thinking I should have waitied until I had the axles apart to see exactly what I had before placing my order.

Well, I still have time before anything arrives, so I'll still work on getting my axles off and then get some pics. this is getting really interesting.

Grady, Randy, really appreciate all your assistance with this.

Randy

[rcecale]

Rats! This stinks!

Finalyy have some time to get back to work on these axles, and find I have NO 32mm socket. Gonna have to wait for tomorrow. Called a buddy from work who said he'll bring it in. So, maybe tomorrow I'll have more than just these 4 pics...



Now THAT'S a spacer!






Looks like the 32mm nut is P/N 900-910-093-02, the self-locking nut. I think I already know the answer to this, but what are your feelings about re-using this nut?

Randy

[randywebb]

I wouldn't re-use a self-locker - kinda depends on the the locking feature. Jim Sims can best advise you if you tell him about the nut. But, why not just play it safe...

"Home improvement chores got in the way again"
- see if you slept in your car, you wouldn't have that problem
(BTW, my eyes are still recovering from the bleach mixture I used 12 hrs ago to kill mold so I could paint the house).

[rcecale]

Originally posted by randywebb
(BTW, my eyes are still recovering from the bleach mixture I used 12 hrs ago to kill mold so I could paint the house).

Haven't you seen this thread????

It just makes sense to replace the nut. Home Improvement chores would be the least of my worries of that thing were to back off of there. I'll add them to the list for round 2 of parts ordering.

Randy

[Fishcop]

Randy, double check the nut size... I've got my hubs apart at the moment for a bering replacement and my nut is definitely 30mm (but it is a much older car - 1969).

Cheers

[rcecale]

John,

I'll take another look with my 30mm. I tried that last night but it seemed the 30mm was just spinning as though it wouldn't go all the way onto the nut.

I've got my buddy's 32mm socket right here, so either way, I should have it apart this evening.

Randy

[randywebb]

Huh - thx for the link. So, if I succeed, it proves I am "dumber" than a retired marine?? I better check this out with some other people I know with hard heads and weathered necks...

[rcecale]

It takes a whole lot of effort to be THAT dumb, Randy! For guys like me, dumbness is second nature!

For instance, I was able to get the axle nut off, after a marathon session with my impact wrench. Popped the axle loose and it started sliding out from it's little hole and BAM! Now it seems the shock absorber is in the way.

Okay, sould be easy enough. Just remove the lower shock bolt and swing the shock out of the way, right? Right? Or, is there something I'm not seeing?

I realize when the shock bolt comes out, the rest of the tire suspension assembly is gonna wanna drop down, right? (I really hate not know the correct nomenclature for these parts. I guess this is where that Bentley's would come in handy.)

Just how heavy is this stuff? I have a brick up underneath the brake disk to support it, but I'd hate to remove that bolt and subsequently crush that brick!

Anything else I should be wary of?

Thanks!

Randy, I hope the eyes are feeling better!

Randy

edit: Oh, almost forgot. The Axle Nut? Definitely a 32mm. 30mm was just too small.

[randywebb]

You got the joke (I guess). Not much fear factor to a pip squeak dictator if you tell him a bunch of intellectual guys are sitting off his coast playing chess .... No comment on tactical innovation ...

Be wary of the brick - I'd put a block of wood under there ASAP. Concrete blocks (& bricks) will fail catastrophically in compression. I know a pic of you bench pressing a 911 will look good to your buddies, but only if it is taken in the first minute or so...

Places like recycle centers, wood treatment plants, etc. will have culls or seconds -- usually the ends off of something they didn't want. I have a nice collection gathered that way - a short 4x4 or 6x6 will be fine.

Well, let eh saga continue...

[rcecale]

Always ready for a good joke! I can take it!

Good thinking, about the brick. Maybe I'll go raid the firewood pile and see if I can't locate a suitable substitute. May have a landscaping timber I can cut to fit.

Just how heavy will those parts be? Is that the Swing Arm...the Trailing Arm...? Enquiring minds are dying to know! Will it be one of those things I can muscle into place with one arm while positioning the bolt with the other. (Keep in mind, I've never been able to bench-press my P-car...not even for a few seconds!!! )

Randy

[rcecale]

Well, I've never claimed I was the sharpest tool in the shed. Pretty much wasted another evening trying to figure out a way to go forward with removing the shock bolt. Was just about ready to call it a day and turn in when it dawned on me. How bout using the jack underneath the wheel brake and lift up on it, releiving some of the weight from the shock bolt. That way, when the bolt comes out, I can lower the arm assembly as slowly and controlled as I want to. It worked on F/A-18s like that...jack under the wing for support, then a wheel jack under the axle lever. Releive weight/pressure and the shock pins came right out.

Any issues with doing it this way I should know of?

Randy