Mike, I sent you some PM's in an effort to keep peace and to calm feathers, I tried to make peace and understand your "math" and view. I did not beg for forgiveness...and it seems you are the first to insult others, but do not have the ability to say sorry.
it is you, that has proven NOTHING, and a video which shows just how wrong you are....

but it seems you have a narcissus type of complex. to bad...\\.... but you still have the mirror......


and my brakes? you had no input, but you sure do now hugh? well, we got it fixed, (no help from the self proclaimed expert here) and it was the valve, but i am sure by your math that it could not have been...

 

Mike, I have to prove not a !@#$ thing to you,But when your presented a video of what you said couldnt happen,you still dont admit that maybe your figures were off some. Instead you come back with excuses to support your bull!@#$.I know that when im told by one person im wrong about something I might argue, when told by a whole crew of people I might have to sit back and rethink my argument. Especially with video showing otherwise. This you will not do. Or maybe you just know everything about everything,which I know you think you do but....... Anyway Ill keep reading your bull!@#$ posts and such,you never know i might learn something else from you. Ive already learned that your perceived intelligence definitely doesn't match your IQ or common sense for that matter.So heres your insult from me,I figured since you liked to dish it out I would feed it back to you.

 

Great idea! Seems like that would resolve this debate once and for all!

A real man admits his mistakes and apoligizes when proven wrong. You resort again to personal attacks and hurl insults reguarding my intelligence, reading, comprehension and experience.
I expected no less from you.

my personal conclusion is that except for a few select members, most of them are keyboard mechanics with little knowledge about what actually goes on. They have their own big bang theory but make it sound like its a science fact.

I couldn't have said it better either.
Think about this quote as you tap on your calculator keys and spew out your next BS theory.

Imagine that! The video disproves this statement. I have seen many differentials on unmodified cars that have cracked posi cases at the pin. The only way I can explain this is the yoke unloading and slaming back into the pin with enough force to crack the case. Any other explanations?

 

Hi, i just had to chime in on this one
im working at nasa this summer and took this question to a few materials engineers, mechanical engineers, aerospace engineers, and other engineers, some of which also have older cars and are familiar with the subject.

anyways, all of these engineers (and i think a materials engineer would be a good source to answer this) have confirmed with total confidence that this cheap, unmacnined, stamped out retainer can withstand several thousand lbs of force, which is more than it will ever see in this sitatuion.

and yes, they did design it to hold the weight of the car. all chevy rear ends are like that. a co-worker of mine went through the same problem and said that putting that clip back on fixed his problem. but it is what holds the yokes in place, which hold the half shafts, which holds the wheel assembly tight in place.

 

And it's not actually the "whole weight" of the car it has to hold either. To get pullled out it's gotta be in the inboard wheel of a turn so the bulk of the weight is on the outboard wheel which is getting pushed to the inside. So really - all the clip has to hold is the weight on the unloaded wheel - untill the tire slides. I can see the clip holding that easily.

-W

 

which is all the more reason for this clip to be the problem.
the reason its there is to hold the yoke tight in place. nothing else holds it, and the clip holds nothing else... so this must be the purpose of this clip

 

I have to jump in here because I was one of the first to say the axle would pull out in turns on the first thread that got deleted. I even wrote an explanation of how and why.

The axle can pull out because the lateral G force can exceed the down force in a turn. Both forces pivot around the same point from the contact point of the tire. Very simple.

And the reason I quoted this part of Mikes post was because when I was just autocrossing with my stock size 255/60/15 tires, they tucked under enough to show wear an inch up the sidewall. If that contributes to the issue than my stock suspension, stock style and sized tire car has the same issue.

 

I disagree, If you stop the video at 1:46, you can see the left tire is loaded and on the outside of the turn and the stub is pulling out.

 

I posted this before, also in a thread that mysteriously got deleted, but if I remember correctly, that cheap looking stamped snap ring installed properly in treated metal, is good up to around 17,000 lbs.
I'm sure GM put it there for some of that capability.

Having some NASA engineers calculate this would be great. Obviously they are used to designing failsafe systems that cannot be fully tested.
Maybe they can use a real CAE program, instead of just a cad/cam to produce a pretty picture.

 

I'd like to see them calcs. 17,000 pounds for how long. A few microseconds?

Please. It doesn't take a mechanical genius to intuitively look at that thing and decide it ain't gonna cut it.

This design is junk. Haven't you heard of c-clip eliminator kits being put on straight axles? They used to walk right out of the housing until you got a crash.

 

The way I see it the c clip only ever contacts the flat inner face of the spyder gear during cornering. The c clip is spring steel snapped into a tight fitting groove in the axle. The axle is a splined slip fit through this spyder gear. Any force the c clip sees is tranfered from the axle to the spyder. This outward force on the axle would only be approx 1/2 the weight of the car (1800 lbs.) at 1 G minus the inward force created from the suspension design and down force. For this clip to fail it would have to shear around the curcumference of the clip or fatigue from repeated hard contact with the spyder. It is adequate for the intended use and minimal load it sees under most conditions. I have seen them fail. For them to fail there has to be a lot of pressure pulling out on the sideyoke repeatedly. If the clip is seeing this type of loading it is obvious to me that if it were not there the axle will pull out until the trailing arm bushing stops the outward movement of the trailing arm assembly. This is what you are seeing in the video. These are the facts and they are undisputed.

 

 

Here, someone with the time can figure out the load capacity of the snap ring with this link.

http://www.americanring.net/rings_thrustloads.aspx

 

Nothing on the stock configuration here is changed on the car in the video. The only difference is the offset trailing arms allow a 1" inset on the tires, the tire size is a little wider than stock and 16" wheels. An auto cross track is usually smooth and flat. Aggressive highway driving and the dips bumps and potholes encountered on the highway change the parameters also as I have raised time and time again. As Mike said this car needs clips. Your car needs clips if you drive aggressively even with a stock car. This suspension system first came out in 1963. Stock tires were 6" bias ply tires. The C Clip may have rarely been needed for yoke control with this tire as it would break loose and slide before it hit the G forces needed to pull the yoke out. The factory tire and wheel width were upgraded twice over the next 6 years then in 1973 radial tires entered the picture. The only change made to the rear suspension geometery in the 19 years this suspension was used, even though there were these tire and wheel changes, was the inner pivot point was raised in 1968. This is the tech and performance forum. There are many cars here on the forum that are mildly modified and have bigger, wider tires even than the ones in the video.

 

A couple of comments;

The drawing listed only shows the effect of a static load and because the shafts aren't level isn't taking into account the car weight. Also no where do I see any indication of what happens during a side load.

Good quality snap rings are made from spring steel 1070 or higher carbon so they are very strong when heat treated. They are loaded in shear and as long as they fit correctly and the groove in the axle doesn't elongate they will stay there. I had a stress Engineer do the calculations on the shear strength of the snap ring in an 1 inch axle and it can be from about 10,000 to 20,000 lbs depending on the material strengths of the axle and snap ring. The axles on my 72 had 135k miles and were barely worn. They Autocrossed for 12 years much of the time with 295/35/17 A Hoosiers. It is my understanding that the quality of axles supplied to GM over the years varied significantly. The best way to make an axle is to machine it from 4140 steel and induction harden it to about 1/8 inch depth. Induction hardening quality can vary tremendously from lot to lot and depends not only on the heat treating but also on the prior heat history of the steel, i.e. normalized steel induction hardens better than annealed. There are much cheaper ways to make these parts and we all know the GM quality was reduced to save costs over the years. This quality issue also goes for snap ring quality, they can be made from mild steel and not heat treated, therefore have much less strength. Some of this could have been that late 70's cars didn't have as high torque motors and someoned decided the stonger axles weren't needed.

The snap ring is in there for good reason the Video proves my seat of the pants experience that since a C-3 does not have an upper A arm the snap ring is needed to keep the axle from coming partially out and causing the tire to a very unsafe positive camber.

 

Finally

It would be interesting to test some NOS yokes for hardness, snaps too. If the hardness ran thru the depth of the snap ring cut, then the shear should be way up there.

On the snap ring, I doubt GM would be silly enough to resort to mild steel untreated, but you never know.

 

with all above.....

great video, it seems that the debate has been resolved... and a lot of interesting information...

 

The non-stock wheel offset (1" inch narrower track), severe tuck under of the tire contact patch and greater overall tire diameter all have a pronounced negative effect on the inward loading of the yoke vs. the stock geometry.

I am truly baffled as to why you or any of the others here cannot understand this.

 

I know why you cant understand why no one agrees with you, Because your closed minded, hard headed and not willing to bow down and say you can actually learn from people with equal or less education.Open your eyes man, your not the smartest person on here. We are here to combine knowledge and learn. Not to claim we know everything about everything. Think about it mike, How many questions do you post? All I ever see you post is answers to peoples questions, and with attitude that most people cant tolerate. Im not your daddy so ill stop now.

 

And as predictable as clock work, one of the trolls feels the need to waste more ink. Being that you've not contributed one bit of technical information to this thread, don't seem to be able to comprehend or acknowledge what others are saying (most remarkably the ones that do agree with the viewpoint), and are here only to be disruptive, why don't you just go away before you get this post locked?