Randy,

That axial end play is normal. The transmission axle flange #12 is
bolted to the threaded piece #3 by the bolt #14. The differential
gear #2 floats (purple arrow) on the splines of the axle flange
#12. It also can float on the splines of the threaded piece #3
but not when in place. The assembly #12, #3, and #2 floats
axially in the differential housing #1. That is the axial end play
you felt. There is also some radial clearance but you probably
can’t feel it by hand with gear lube in place.
IMAGE 915DifferentialNormal02
"
http://forums.pelicanparts.com/uploa...1119386974.jpg "
(C) 9/1972 Dr. Ing. h.c. F. Porsche A.G.


Now, what was causing your noise? Did it just go away?

Best,
Grady

BTW, I wonder how many wrong spec versions of Bentley
are out there?

Grady, you don't know how great those words from you were to read...really! :D I'll sleep much better, and drive better too, just having read them.

As far as the clunking noise, I haven't been able to tell if it's still there or not. I just got home from work and was going to head out and drive her around a bit to see. Perhaps it's just coincidence, but the axial movement of the flanges didn't seem as drastic after I got it all back together. Maybe the new seals were just a little tighter and didn't allow for the same ease of movement as the old ones.

I'll give her a ride and report back what I find.

Randy

"CLUNK!"

Well, it's still there. ARGH!!!!

I'm trying to pinpoint where exactly's it's coming from, but with my back to it, it's rather difficult to tell. It's definitely coming from the back end though.

At first it sounded like the outboard CV joint on the drivers side...right behind my left hip. Then, a few minutes later, it seemed to move toward the center of the car...one of the drive flanges or most like, one of the inboard CVs.

There was nothing I could do intentionally to make the noise, it just happened at random. The streets around my house are quite twisty, and there are several cul de sacs that I could corner in. Some hard, some more gentle curves. Again, it just happened when it wanted to. Even backing out of the driveway didn't produce the clunk 100% of the time.

I'm afraid to say this, but I really think it may be my CV joints...maybe one, maybe a couple of them. But this seems to make the most sense.

They looked okay when I had them apart though, that's what digs at me. I mean, I'm no expert with a trained eye, but I did look at them and noticed NO wear indications. Unless you've got a better idea, I'm afraid I'll be ordering a new pair of axles in the very near future. :(

Randy

Doug,

That was pretty much the gist of it.

1.) Pop this cap off.
http://forums.pelicanparts.com/uploa...1116691755.jpg

2.) Remove the circlip from the end. http://forums.pelicanparts.com/uploa...1119400982.jpg

3.) Cradle the sides of the CV joint and press it right apart.

Putting it back together was a bit more tricky, but basically, just the opposite.

Randy

This is a great thread!

I WISH my CV bolts would back out! :)

Randy,

Sorry.

How about a “better” description of the “clunk.”


Is it a single noise once and a while?

Is it a “snap” or a “thud” on the range of how sharp or dull the noise is?

Is it rhythmic with the wheels or engine speed?

Will it do it when costing, in neutral, or the clutch disengaged?



OK, on to your CV disassembly – assembly procedure. Did you support the CV by the inner race or outer race when pressing off and on? I can’t tell from ”3.) Cradle the sides of the CV joint and press it right apart.”

Best,
Grady

Randy,
I appreciate your attention to my question. I understand how to disassemble. I just was curious about the press itself and how you set that up. I don't have a shop-style hydraulic press. Did you use some other tool to make it work?

Thanks,

Doug

My car is in the shop with what sounds to be the same symptoms. I have not heard from my mechanic yet, but hopefully will have an answer soon. I'm learning a lot from thos thread, thanks Randy and Randy.
David
Ps my car only makes tha clunk in gear and clutch engaged

Yes, a single noise, occuring randomly. It does seem to happen practically every time I transition from my driveway to the street. There is a little dip where the lowered curb meets the asphalt.

Much closer to a snap than a thud. It has a "crisp and solid" sound to it. Similar to a slide hammer, or rapping the handle of a breaker-bar against a brake caliper (installed)

Nope, it's more of a single clunk, occuring when there is a change in attitude of the car. While travelling in a straight line, I don't think I notice it. Around curves seems to be the times when it happens.

Haven't really tried neutral, but if I am coasting with the clutch pedal depressed, it can and will make the sound. My driveway has a slope to it, and my car sits fairly low, so I tend to take the transition from into and out of the driveway at an angle. I usually am coasting with clutch disengaged at these times. Again, I do hear it most of the time during this transition.

The best way to describe where I supported the CV joint is with this pic. The red blocks serve to indicate the support block positions. Hope this helps!

http://forums.pelicanparts.com/uploa...1119409880.jpg

http://forums.pelicanparts.com/uploa...1119409911.jpg

Randy

edit: I suppose it would be nice to see the pics I spoke of. ;)

Randy,

The noise is consistent with a damaged CV. I would take a look. I know that isn’t what you want to hear but better safe ….

What may have happened is the outer race got supported and not the inner. Many times I’ll bet the CV will press on the splines without any damage. If it is slightly cocked and takes force, some of that force is transmitted to the cage and it can crack.

Now that you have the illustration, I’ll bet that is what happened. Notice the two arrows in the Bentley instructions.

The CV has to be pressed off and on with the tin piece pushed back and support the inner race (hub). The outer race should be free to move (axially and wobble) during this process.

Sorry ....

Best,
Grady

:(

Thanks Grady. I was afraid this was the case. Looks like I messed them up myself. That has to be the hardest part to swallow.

Rather than rushing out and buying a pair of new axles, I suppose it would be worth my time to just pull the axles apart and have a look/ Who knows, maybe it's only the inner CV joints. (Wishful thinking, I know...:( )

The alternative to this would be to just spring for the new axles, install them and be finished with them. Sounds easiest, that for sure.

Argh!

Well, thanks again for the info, Grady! As always, you were right! Definitely not what I wanted to hear. If nothing else, I hope this thread helps others when it comes time for them to mess with CV joints.

Randy

just spring for the new axles....

- nuh uh. you are too far in now. no wimpin' out and buying something...

BTW, if you install and remove the CV's 3 times, it gets easier to do - ask me how I know...

Randy,

If there's a way to repair my CVs, I'm all eyes!

I've got the newer axles, with the outboard CV incorporated into the stub axle. I don't believe these are repairable.

My axle:
http://forums.pelicanparts.com/uploa...1117151362.jpg

I know I can replace the inboards, but the outboards, from what I read, if they are worn, require the replacement of the whole axle.

If you know of a way, do tell. It's gotta be cheaper than new axles. :(

Randy

Randy,

When you had the axles out, did you do anything to the outboard CVs? Did any of the press loads go through them when you were disassembling or assembling the inboard CVs on the axle shaft?

I would suspect that only an inboard CV is damaged (probably left axle from your description.) You could get one CV and replace just the damaged one. You should be able to easily tell the damage. Run your finger around both ends of the cage. You should find a crack or broken cage pieces.

HELP
When you were doing this a month ago, I picked out about 10 pages in a Factory workshop manual and a friend scanned them and sent the file as e-mail (he uses the manuals all the time for his shop employees.) They have a .jsd extension and I can’t open them. Does anyone have any ideas? It would be worthwhile to compile an exact set of instructions for this operation. I can e-mail someone this file (2.7M).

Best,
Grady

Grady,

Tried sending a PM but your box is full. I tried an EMAIL.

I only have two in-boxes; snail-mail and e-mail (gradyclay@hotmail.com)

Best,
Grady

Like Grady said -- but, you know, the longer this saga gets, the less I like the "improved CV assemblies" - not sure what P AG was thiking...

Randy,

A few weeks ago I was talking to some PCNA techs about this subject. Their opinion (not PCNA’s) was that the bean counters and engineers are always at war. Nothing new there. The money side got rid of the Schnorr lock washers for a while and forced the use of the 923 (912E M8 bolts) axles and the weld-on 108 mm CVs. The result was a spate of CVs coming loose on brand new cars. Warranty claims soared. The engineers got the parts that should have been there from the start. The “Turbo” axles (actually a 928 P/N) are clearly what should be on the cars IMHO. I’ll do some searching to see if there is any campaign. Yes, they are more expensive to manufacture. You have separate stub axles, 24 M10 bolts, 24 Schnorr washers, 12 plates, and replaceable/serviceable CVs on the axles. Just like ’69; some overkill but last a long time (Those great big CVs were on ’69 912s also.)

It still doesn’t preclude torque the CV bolts just after assembly and some use and periodically at a service. I don’t think anyone has a handle on why we hear of so many CVs coming loose. The Bentley spec error and some people using M8 torque on M10 bolts are the only definitive things I have seen.

I would like to hear some feedback on how much the CV bolt turns (if any) when re-torque after the first installation. After a second torque, has anyone experience with painting the bolt-Schnorr-plate-cover with paint of nail polish to tell if there is movement?

Best,
Grady

Well, I didn't do anything "intentionally" to them. Intentionally, all I did was remove the boots, cleaned them out as best I could, greased them back up and installed new boots.

Unfortunately, when it came time to press the inboards back on, the load from the press DID pass through the outboards. Basically, I supported the outboards and pressed down on the inboards...supporting the outboards in the same location I indicated previously with the red blocks. So, there is a good chance that the outboards are toast too, I suppose.

The first clunk I heard last night would support that because like I said, it seemed to comes from right behind my left hip...outboard driver's side. After that, though, they did seem to come mainly from the center of the car.

I'll have to drive the neighborhood tonight with my wife and have her listen. Maybe, if she's lucky, I might even let HER drive so I can hear. :eek: LOL

Grady,

As far as the .JSD files, there are a few different programs that use .JSDs. The most likely one would be Paint Shop Pro . You can download a shareware version and check it out. I DID find this though...
http://forums.pelicanparts.com/uploa...1119467234.jpg

If you want, you can e-mail them to me at rcecale@hotmail.com.

THANKS!!!!! :D

Randy

Actually, PSP wont open this type file. I've tried several programs but with no luck.

It appears the source is Jet Suite Pro which is a program that is bundled with drivers for Oki / HP multi function machines. Only available on CD with the machine.

I managed to find a copy that works with Win 95/98 but not with 2000/XP/NT so I can't run. :(

Grady, Do you have access to 95 or 98 at home? I don't presently. I'll be happy to send if your email can handle a 40 M zip file. (Or I'll provide a link that will require registration so you can download).

Rick, I must have just missed your post before I left work. Really wish I'd have seen it. I'm pretty sure I have this software on one of our servers at work. Could have (and WOULD have) stayed late just to make these files available to everyone.

If you have the files and want to e-mail them to the above address, I can VPN into work and download the drivers for an HP OfficeJet 600. This should do the trick.

Randy

Randy, As long as you have Jet Suite Pro it should work.
I installed a large all-in-one package from a new HP MFM here at the office and it didn't fly.

I'll try at home and send the file to you now.
I'll also send the package software to Grady (if he wants) for future use.

Grady, Rick,

I was able to open the .JSD file you sent me. Found a program called eFax Messenger that worked like a champ.

Using eFax, I saved the .JSD as an .EXE which includes a small viewer, incorporated into the file. You can open it on any computer running Windows, just like it is.

If anyone else wants a copy, PM me and I'll send it right out.

Randy

I now have Grady's document in .PDF format if anyone else is interested.

Just send me a PM.

Randy

ok, just to clarify some things...

I have the 10mm bolts which will need replacing. They are installed w/ the moon plates, but I do not see the schnorr washers there. Everything fits well, but I have no idea what length of bolts to replace them with.

I don't have the facilities where I can just pull one out and measure while the car just sits there, so when I get in there, I'm going to have to get it done and move on.

To prevent a holdup, I'm going w/ the shotgun approach of getting 45mm 50mm and 55mm bolts, M10, 1.5 thread, 8mm hex. McMaster-Carr under the 45mm bolts has a choice of full thread or partial thread on the bolts. The 50mm and 55mm only come w/ partial thread. Is full thread an improvement or does it actually weaken the bolt?

thanks.

edit: can, or SHOULD, these be made from stainless?

edit 2: are the washers serrated on both sides or just one?

weakens - but I wouldn't worry too much about it

Regarding the inner clamps for the CV boots and the special pliers needed to properly crimp them: I've always discarded those damned things in the past and just used largish zip ties clipped off near the boot. Don't get them too tight, but enough so the boot can move a little. Not much motion there, so they last a long time.

ianc

Randy,

My humblest apologies. :(

I haven't been back to this thread for a while and am just now seeing this question. I was able to convert the file over to a .PDF you can open with Adobe Acrobat Reader. If you like, I can e-mail you a copy of it so you can see for yourself. The file is on my computer at work, but I can access it from here if you want it. No problems.

Randy

Grady:
I've been reading this thread wondering if I should re-pack my CV's. I've got an early 84 with the M8 50mm bolts with the 923 paper gasket on the ends. My CV's don't have the end cap & seperate from the axle flange (no friction weld there). Can this cap be installed as an upgrade and is it placed on both ends of the axle (axle & tranny flange)? Does the end cap replace the paper 923 gasket?
Regards,
J.P.

J.P.

I’m glad this thread got resurrected; there is still much detail to post.

To answer your question in a word – no. The end cap requires a different flange at both the stub axle and transmission flange ends. There are two points of contention. First the clearance dimples in the cap don’t clear the mating shape of the flanges and stub axles – there is interference. Yes, you can carefully Drimmel away clearance in these parts but it is way too much work for any return.
The other issue may come back to bite us. The CV or flange is relieved to accept the gasket. There is a completely flat surface (no relief) when the end cap was used. This changes the clamping pressure given the same torque on the bolts. The end cap also inserts an intermediate piece of steel between the CV and flange. I can’t tell you if the net result is to improve the clamping and reduce the likelihood of a CV bolt loosing its clamping or not. Paging Jim Simms.

It is a simple process to replace the CV boots, clean & re-grease, and assemble with new gaskets, CV bolts and Schnorr washers. The devil is in the details, ask Randy. Most (but not all) has been covered in this thread.

If you have any intention of anything more than minimal track use, I would replace the entire axle assemblies, stub axles and transmission flanges with the later “Turbo” 108 mm version (928 P/N.) That gives you end caps, M10 CV bolts and the much stronger CVs.

BTW, does your ’84 have the OE “moon” plates between the CV covers and the Schnorr washers? How often do you re-torque the bolts? Do they move each time? What torque do you use? Do you know the precision and accuracy of your wrench?

Best,
Grady

Grady:
My CV's don't have either the half moons or Schnoor washers. I had them cleaned @ 50K miles and now with 90K I'm contemplating another cleaning. When the tranny was freshened up @ 65K I found the CV bolts loose after 60-100 miles; at first I thought the mech hadn't torqued them properly, but after reading these posts, it looks like it's common to tighten them up after fresh gaskets are used. About a year and half ago the synchro's were replaced and I didn't check the CV bolts after engine instalation. I'm heading over to the car today so I'm going to do a random check.
BTW, during the 90's I used to to DE the car quite regularly and the CV's have held up very well. The LSD was set to @ 80% lock, I wonder if this wears the CV's more; what do you think?
j.p.

You need to use the half moons and esp. the Schnoor washers!

And yes do check the torque after a few whundred miles

Grady:
I got this M8 bolt kit from McMaster-Carr; it includes 25 M8 12.9 Metric Blue allen bolts (176,00 psi) and 100 M8 Schnorr washers. I'm surprised the CV's came from the factory without the moons and washers; I must have been very lucky they never came loose.
j.p.

http://forums.pelicanparts.com/uploa...1126400900.jpg

J.P.

Good for you.

Now, after you torque all the bolts to spec noting if or how much
they turn, remove one bolt. We want to inspect the condition of
the tin boot attachment where the head of the CV bolt sits. That
tin cover is very soft steel and probably the bolt heads have sunk
into it. This deforms the cover and leaves a raised lip around
where the head of the bolt sat – not good.

Measure the length of the bolt from under the head. (Measure a
new bolt and confirm it is 50 mm.)

Next find a suitable flat steel washer that is the same thickness
of the new or good used half moon washer plates that you are
going to use. This one measures 2.36 mm thickness.
IMAGE: CVWasherPlateM8a.jpg
http://forums.pelicanparts.com/uploa...1126405254.jpg
Using the used bolt and a new Schnorr washer and the
temporary flat washer, torque the bolt in place and confirm
the threads come out the other side of the flange. MIL spec
(and DIN) is 1 ½ turns of thread. Less than one turn is too little
and more than two turns in too much but acceptable under some
circumstances.

If you use a too long bolt, you must pay attention to the end of
the bolt clearing the transmission casting on the inboard and the
trailing arm on the outboard. The real problem with too long bolt
is that many threads are exposed to the road environment and
can collect grime and sand. When you go to unscrew the bolt,
that grime and sand is dragged into the threaded flange and can
do damage to the threads.

When finding a suitable washer, pay attention to the OD. Too
large and it will ride up on the tin cover where it transitions from
flat to clear the CV balls.

Through this 1-bolt exercise you have determined how long your
new bolts need to be. It is a fair assumption that all four CVs
are the same but pay attention when you do the final assembly.

Put the used bolt back in for now (with new Schnorr washer) and
torque to spec.

In your picture, the bag of washers doesn’t have the Schnorr
logo. Are they the real thing or simply radial toothed conical
spring washers. Schnorr washers have the teeth set at an
angle to the radius and are sharp.

Here is a prior thread.

Schnorr homepage

Adolph Schnorr GmbH & Co. KG
Stuttgarter Strabe 37
D-71069 Sindelfingen (Maichingen)
Germany

Schnorr Corporation
4355 varsity Drive
Suite A
Ann Arbor, MI, USA 48108
Phone 734-677-2683
Fax 734-975-0408

Here is the link for the Schnorr washer technical data sheets (pdf).

Here is their contact:
sales@schnorr.com


OK … please report back what the tin cover looks like under the
head of the CV bolt. If too damaged, you will want to replace
them with new tin pieces when you clean the CVs and replace
the boots.

When you get some half moon washer plates, you will want to
check for proper clearance fit on the tin covers (as you did with
the single washer above.)

Best,
Grady

Oops :rolleyes: To answer your LSD question – yes, it does add
some wear. It is probably about the same percentage as the
increase in rear tire wear from the LSD.

Grady:
I may have made a mistake in ordering the bolts. PET states the OEM units are 50 mm; now keep in mind my car came without the Schnorr washers and moon units; they may be to short if 50 mm is flush with the backside of the flanges, I'll need to check.
As for the washers, they're not Schnorr brand, rather Belville dual side conical serated washers (as per McMaster-Carr).
The teeth are pronounced but not sharp as you describe; should I get the real ones?
Looks like this car was a victim of the bean counters.
j.p.

From McMaster site:

Shape Belleville
For Screw Size 5/16"
Belleville Shape Serrated Top and Bottom
System of Measurement Inch
Inside Diameter Range .25" (1/4") to .349" (11/32")
Inside Diameter .25" (1/4") to .349" (11/32") .331"
Outside Diameter Range .4" (13/32") to .599" (19/32")
Outside Diameter .4" (13/32") to .599" (19/32") .512"
Minimum Thickness Range .02" (1/32") to .049" (3/64")
Minimum Thickness .02" (1/32") to .049" (13/64") .028"
Height .055"
Application Locking Washer
Specifications Met Not Rated

http://forums.pelicanparts.com/uploa...1126413386.gif

J.P. said; No big deal, you may just have some extra bolts. The important thing right now is to inspect the tin covers, find your existing bolt length and get the appropriate washer plates and other pieces.


J.P. said; I’ll e-mail Schnorr here in the States and ask questions and get the sales pitch. Porsche has been using their product since about ’66 so they should be able to provide some insight.


J.P. said; That seems to be the common perception. It would be interesting to have been a “fly on the wall” when they decided to only use 928 axles (108 mm CVs) and go back to using “half moon” washer plates and Schnorr safety washers.


I added this link to the pdf product specs in my above post.



Who on this Forum has the ability to measure the hardness of steel parts?
It would be very instructive to know the relative hardness of the surface under the CV bolt head, the Schnorr washer, the “half moon” washer plate, the tin CV cover, and the outer race of the CV.


Another issue that needs to be addressed is the compression of the gaskets (when used) and the compression of the sealant between the CV and the tin cover (when used). If those things must “settle in” to their compressed state before a final torque, we need to know that.

There is also the issue of the increasing layers of the “sandwich” that the bolts compress. On the latest version there is: The bolt, Schnorr washer, washer plate, tin cover, sealant, CV outer race, sealant, tin cover, and finally the threaded flange or stub axle. Some engine management and data acquisition systems use a tooth wheel under the CV bolt heads to sense axle (road wheel) angular speed.

With CVs that use a gasket, there is the issue of gasket edge parts getting between the steel clamping surfaces.


Let me repeat something that has been said many times. The CV bolts do not transmit the axle driving torque in shear or bending, they only provide the clamping force. It is the shear friction that transmits the driving torque and is from the high pressure provided by the CV bolt clamping force. This is the reason why it is so important to maintain the highest clamped pressure for the steel-to-steel surfaces.

Best,
Grady:)

Grady:
Here are some pics of the M8 washers. After looking at the Schnorr site; visually they seem identical. The flash reduces the black oxide finish. I have these in M10 and M12 in zinc finish, the width ratio seems reduced with the larger sixes.
j.p.

http://forums.pelicanparts.com/uploa...1126452935.jpg
http://forums.pelicanparts.com/uploa...1126452963.jpg

J.P.

http://forums.pelicanparts.com/uploa...1126456499.jpg
My recollection is that the Schnorr washers (lower) have a
pronounced and sharp “rake” to the serrations and that the
normal Belleview serrated washers (upper) have symmetrical
serrations. My perception is that a surgeon would want to be
careful handling a Schnorr washer with bare hands.

I’ll ask this question of Schnorr.

Best,
Grady

Grady:
I'll try to get the pics you requested of my CV's today. I'm very curious to see the condition under the bolts.
j.p
PS. I used a loupe to look at the serrations; they have clockwise pattern with the trailing edge having the bite. Not as pronounced as the lower image you show (Schnorr).
PSS. 'Just checked the M10 & 12 washers, those are quite dull.

proposed edit:

"It is the shear friction [and on some versions, the projecting pins] that transmit[] the driving torque and [it is generated by] the high pressure provided by the CV bolt clamping force." [That is why the proper torque is ESSENTIAL.]

BTW - any testing lab - including those in engineering depts. at Ag. Univ.s will have the machines to determine hardness. I know there are some students on this bbs that could prob. wangle their way in...