Please help me feel better about my CV-Axel installation

[FL911SC]

Car is a 1979 SC Targa with a non-LSD 915 transaxle and stock 3.0L.

Late last week I removed the axles from my car to have them cleaned and inspected as the cause of a loud bang sound (here).
On Friday I sat down to order the needed gaskets for the reinstallation. I needed some help understanding what the parts manual was showing so I gave the folks at Pelican a call. I have a huge amount of faith in the Pelican team, but I need a better understanding of the answers they gave me.

1) According to the parts manual, only two gaskets (#19 figure 1) are needed (one per side) for my transaxle type. I asked the person at Pelican and he confirmed this and said the gasket would go on the top of each side (axle to transaxle joint). My questions, if the joint at the transaxle is effectively the same as the one at the wheel hub, why is only a gasket at the top needed?

2) I asked about the “moon” plate/lock washer (#22 figure 2) which my car didn’t have, but I have seen these as a recommended part in the forums. Turns out, according to the parts manual, these are only for Sportmatic transmissions. Since this is the case, why are people recommending them for non-sportmatic installations?

3) Washers… The first time I removed the axles there were no washers (#21 figure 2) on the bolts. Also according to the parts manual there should not be a washer. At the recommendation of several threads I ordered and installed the M8 Schnorr washers. When I was installing the newly rebuilt axles, on the outside of the car (both sides) the bolts seemed too long and were hitting something not allowing the hub to turn. I backed the bolts out and added a split type lock washer in addition to the Scnorr to give me the clearance needed for the axle to turn.
For this go round, I have ordered a thicker two part Scnorr type washer to replace the Schnorr and split lock washer.
The question is, if there were no washers from the factory (per the parts manual) and I used the exact same bolt length plus a Schnorr washer for the reinstall, then why would the bolts be too long causing them to run something on the other side of the wheel hub?

Sorry this is so long, but I try to be clear with my questions. Thanks for reading through it and for your responses to help me feel better about installing the axels correctly.

~Keith
Figure 1


Figure 2

[L8apex32]

Couple of things from my experience. I have an 1981 SC. The bolts that hold the axle on are different lengths on the inside (by tranny) and outside (to hub). Organize yours in groups, by length first. Someone can probably tell you which way the longer ones go or, if you have a conflict, switch the long ones to the other side.

As far as replacement axles, replacement axles usually come with the correct bolts to work with the new axle - at least for the inside if my memory serves. Again, bolt length matters and it is different inside to outside. And, the thickness of the axle hubs (on the axles) are different between OEM and what you can get now from vendors - so stock length bolts may not work with aftermarket axles.

These bolts are available from hardware stores if you find you need a set a little shorter or longer.

My understanding is that Schnorr washers are the correct washer.

I have had my bolts back out on the race track, and so have others. It is important to torque these bolts to the correct torque, and to use the washers, to prevent them from backing out. I believe 28 ft-lbs is the spec and I know of at least one mechanic who uses 32 ft-lbs and found 32 to work better.

I hope this helps.

[FL911SC]

Thanks L8apex32.
The axles and CVs are original, but were rebuilt. When I put them back in, I did use brand new bolts (ordered from Pelican) since several of the originals did have damaged heads. When I ran into the problem of the wheel not turning during the install, I compared the old and new and they all looked to be the same length. I kept some of the old ones as spares so I will look at all of them and check the lengths.

Are the two ends of the CV the same, or is there an inside and outside CV to allow for the different length bolts?

[L8apex32]

If I recall, the axles are symmetric. It must be the hub/flanges that are different which causes the need for different bolt lengths.

[OsoMoore]

I've done both sides' axles of my 79 SC targa non-LSD.

I have not used any washers, but have heard good things about them. I did discover that one side (I believe the transmission-side) has less clearance and requires shorter bolts than the other side. The issue is that different boots add different amounts to the length of the hole in which the bolt goes.

First type boot

            |--|
   /--\/-\/-|  |
--          |  |
--          |  |
   \--\/-\/-|  |
            |--|

Second type boot

            |
   /--\/-\/-|
--          |
--          |
   \--\/-\/-|
            |

Because of the thinner collar on the second type, a bolt which was the right length is now too long. I believe 50mm was the correct length for my bolts with the boots I obtained from PelicanParts.

Also be careful when torquing the bolts. The 101 projects book has the incorrect torque spec for the bolts! If you try to torque them to 61 ft/lbs you will break them off. Instead they should be torqued to 34 ft/lbs.

Finally, a week or 100 miles after you install the new joints, take your wheels off and re-torque the bolts. Do this again the next week. The second time, you should find they do not need any tightening at all.

[Trackrash]

Sorry to hijack, but I have a couple of questions that are related.

If grease is on the bolt's threads could that lead to the loosening of the bolts?

Does anyone ever use locktite on the bolt's threads?

[FL911SC]

Osomoore,
Thanks for the information on the boots. That is interesting and helps since I have been racking my brain trying to understand why bolts that worked once didn't work after the rebuild, when nothing was changed except the boots.

I usually get my torque values from Bentley since they are easier to find, but thanks for the heads up.
Lastly, I was aware of re-torquing the bolts after 100 miles.

Any one have any thoughts on the gasket question?

Thank you.

[FL911SC]

Originally Posted by Trackrash

Sorry to hijack, but I have a couple of questions that are related.

If grease is on the bolt's threads could that lead to the loosening of the bolts?

Does anyone ever use locktite on the bolt's threads?

Yes, grease on the bolts can absolutely lead to them loosening. You need to clean both the bolts and the holes before the final installation of the bolts.

As for locktite, I haven't read of anyone using it. To be honest, the Schnorr washers (found on the McMaster-Carr website) do an outstanding job of holding the bolts. You still need to do a re-torque 100 miles after your installation, but after that you should be good to go.

[RDM]

I will be putting my driveshafts back on tomorrow. Was going to be today, but life intervenes….

Mine had two gaskets per joint when I took them apart, so they'll go back in with 2 gaskets per joint. I have new bolts, and am now hoping I don't have the problem you're having since all the bolts I ordered are the same. No point in worrying; tomorrow I'll know.

[pete3799]

If your stub axle has a recess for a gasket and the boot has a recess you'll need 2 gaskets per CV ( 8 total). Measure the thickness of the CV's you may have some that are thinner than the others.

[stormcrow]

Keith,

One of the things you need to pay attention to is to make sure the bolts extend through the housing with at least two threads showing. When I replaced my CV joints the metal boot ring lip was thicker then the one I was replacing

I installed the new CV joints along with new boots. Torqued everything down and figured everything was OK. Well about a week later after I did a second check on the torqued bolts, the drive shaft on the drivers side came apart.

What I found out was that the bolts did not protrude through the housing and as a result came loose. When I installed the new bolts there were long enough to allow me to put a lock nut on the end.

Haven't had a problem since. So make sure you pay attention to the bolt length - it needs to show two threads after being torqued down.

[FL911SC]

Thanks to all who provided some valuable feedback. It is amazing, and a little intimidating to me, how much of these cars is "figure it out as you go".

Based on my previous installation and from all the feedback here, for my application, it would seem the following will be the case:
~ I will stick with the M8x50 bolts and adjust the length as need using lock washers. I don't think they are too short but will ensure there is proper thread engagement.
~ I will use four gaskets (no just two as the parts manual states) placing one at each end of the axle. I don't think I need two per end.
~ And of course I will retorque all 24 bolts after 100 miles to 34 ft-lbs.

Lastly, since no one commented on the "moon" spacers, I will assume they are not applicable to my situation and won't worry about them.

Thank you again to all.

~Keith

[ClickClickBoom]

Read this:
Reconstructing Constant Velocity (CV) Joints
If you still have questions, re-read.
Sorry to say, lots of less than accurate advice/ideas in the previous posts in this thread. Beware, the 8MM bolt is a 12.9 grade and in this application is very close to its design limitations, so proper attention to detail is required.

Originally Posted by Grady Clay

As everyone can see, there is much opportunity for mischief. The wrong torque can be used, the wrong parts installed, a PO “quick fix” left in place, and much more. This Forum has had way too many accounts of CV attachment problems. This is a serious life-and-death situation if a CV comes loose at speed or at just the wrong time.

Best,
Grady

[hbkramer]

Waynes book torque values are correct. The poster above did not read them correctly....There are different torques for M8 and M 10 hardware !