So your stub axles don't pop out when you jack up the rear. Or if you actually do manage to corner hard enough to get a wheel airborne I suppose.

Bear in mind I don't think anyone is suggesting it's a good practice to drive around without them. It's just the whole zealotry behind checking stub axle endplay is misplaced and misguided. All that really matters is that the c-clips are there, and the stub axles aren't hitting the pumpkin anywhere.

 

I agree with Paul on this one. Those clips are all about the cornering forces. When a car is going around a corner and since not all roads are exactly flat nor completely smooth the clips are there to keep the rear from allowing any additional geometry changes due to several factors inherent to the design:

The trailing arms have a bit of play because of the pivot point and overall design.
Sway bars have enough movement to be pretty useless to prevent this and not all cars had them anyway.
The shock mounts are the same way because of the rubber bushings and are for dampening the vertical forces.
The tires of that period had a lot of sidewall flex in them which adds to the problem.
The rear spring is mounted in such a fashion that movement will occur once the suspension is unloaded.

I can also see the clips serving another purpose as well. When the suspension is pushed to the extreme position which allows the axle to move further away from the center pin and then it returns with that equal opposing force the axle will hit the center pin that much harder causing more wear and tear on the rear carrier components.

I find it hard to imagine that the engineers at GM would require the axles to be machined, the clips manufactured and the installation performed just because it makes sense. They serve a specific purpose else the accountants would have removed them from the design.

This is all just my opinion and is not based on scientific facts gathered during controlled reproducible experimentation.

 

Have any of you guys who don't think yoke end play could possibly matter actually ever seen a close up video of what all goes on in an actuall (not theoretical) C3 rear suspension during high cornering loads?


OMG, hope this thing doesn't turn into another PCV or C6 wax debate.

 

No, but I'd love to see one.

On your second point, I wonder when this thread will get deleted like the last one?

 

Ok, I humbly disagree, and stand by my thoughts...

in the pictures below you will see (ok, yea yea ... i know it dirty, its all under 5K miles... man it gets dirty fast!) a very familiar site to most of us, so... you are saying with a very high lateral G force, with say high performance wheels pulling near 1g that the camber strut rods set ~2" below center axle take ALL lateral load in both directions all by them selves? keeping in mind that these rods are again ~2" below center axle, on a pivoting point at each end? and the trailing arm is what??? 3' long?.. made more for non-forward non-backward movement..... I am having a hard time believing this, but.... I could be wrong, I am not a suspension engineer...I am just going by observation and my past experience of having this problem..







but if I am not understanding something properly, please explain it to me in simple terms someone like me can understand... thank you..paul

 

As someone who has rebuilt many second and third gen. diffs, i've seen the damage caused by the stub axles being allowed to float without snap rings. The purpose of the snap rings is to prevent the stub axles from hammering the cross shaft when the rear of the car gets light, like crossing a rail road track at speed. Not to mention, the axles serve as the upper control arms to the rear suspension, and I don't see how anyone who understands suspension geometry can think it's ok to have play in your upper control arm. We stress so much about bump steer, but it's ok to let the rear move all over the place to save two snap rings? Really? What am I missing here? It's two snap rings. If you're trying to save weight, why not leave the bushings out of your front control arms too? Seems by what i've seen posted, the weight of the car and the lateral loads won't affect that either. Just my two cents.

 

I can see the c clips being left out with a dragvette 6 link setup with no problem, Probably the way to go. With no other upper control arm like a stock rear suspension it doesn't make sense to me.
The big issue with the OP that no one else seems to address is that he has about 1/4' of play at each side yoke. That means that about 1/2" of shaft x the shaft diameter of metal shavings and probably 2 c clips are mixed into his rear end fluid and is getting flung around and violently circulated throughout the bearings and gears. I just don't understand how anyone with any common sense let alone an engineer could figure this is a nonissue and will not cause further damage. These cars have close to 50/50 weight distribution.
The preload due to the weight of the car has been determined to be #300. When you hit a corner hard you have aprox #1800 of car weight pushing sideways @ 1G + Then hit a bump or pothole. The axle unloads and then slams into the center pin. Could see a cast posi case cracking from this. My math must suck but I do have common sense.

 

Thank god, I'm not the only one. I have yet to see a case break, but i've seen many cross shafts worn halfway through and stub axles so worn and mushroomed that i couldn't beat them out of the spider gears with a three pound hammer. I don't understand why people are making such a stand against common sense. Just put the snap rings in!

 

Thank you, True Blue.

 

You're not listening.

Nobody said that they shouldn't be installed. Nobody

What I said was the issue of endplay is vastly overrated because the stub axle is very rarely yanked outward in the first place. And when it is yanked outward it is not because of the loading of the suspension, it's because of the unloading. Those clips are not intended to support the weight of the car. Not counting Mike, I see at least 2 other people that understand this.

Correct, you unloaded the axle, the suspension relaxed, the c-clips are not supporting the weight of the car. They're just giving you a lower bound on the suspension travel.

Again, correct

I will reiterate. Nobody here said that they should not be installed. They should be to account for the extreme situations noted above among others. The points was that excessive endplay is not the end of the world as some would have you believe because it will not even come into play in 99.999% of the miles you drive.

 

What about all the metal shavings and chunks of c clip floating arond in the rear end?

 

The strut rod is in constant tension.
The half shaft is in constant compression.

The trailing arm assumes fore/aft loads only. The front trailing arm bushing (by design) must allow torsional movement to permit the trailing arm to describe a slight arc though it's up/down travel as viewed from the vehicle rear (camber change)

That's about as simple as I can state it.

 

I agree with most of what you say.... but

What I do not agree with you on is the "CONSTANT TENSION." Take a pencil put a small rubber toy wheel on one end and slide that wheel sideways by ether pushing or pulling on the pencil. If there is any grip on the wheel it will flex a little and want to put the pencil on end or over, thus the wheel IS trying to move or flex side to side, not just inward, but outward as well depending upon the direction of the lateral slide.... you can not control this movement with 1 strut rod 2-3" away from center..... Again, I go back to when I had a chewed yoke and had excessive movement allowed at the axil, and it felt like a boat on hard long turns...fixed it, problem went away.

so, please enlighten me how is it posable to always have at all times a positive pressure on the half shaft, and have 0 float or negative pressure at any time, even when the wheels are in hard turns of all sorts?

I believe what you are saying is that the half shafts ALWAYS have a load on them under ANY conditions short of hitting a curb of fatal accident...and I do disagree....

in the second to last picture, you can see that the rod attaches 2-3" below center axil, also where the shock attaches, also notice that the rod is on a pivot, thus letting the hub have greater freedom of lateral movement (what we do not want) so.... the only thing else to secure the hub from left right movement is the axil.

 

OK, please do this. Take out the half shaft and put the car on the ground. Which way does the wheel twist? How many pound pressure does it take (pushing at the center of the wheel) to keep it upright?

Clue: answer is 300 lbs.


Home work: Why is the answer not 0 (zero)?

 

ok.... lets just say for now you have 300 lbs of inward pressure, and yes I am sure you do have quite a bit of pressure.,.....

What I am saying is 300lbs of pressure can be over taken with a 3500 lb car...in a hard lateral skid or thrust, or even better a quick swaulum (sp???) thrust from one side to the other quickly.


also....I just want to clarify, you are saying the half-shaft, ALWAYS at ALL times, even in the most spirited of driving with hard shifts left and right, will have a positive inward pressure?

thats hard to believe

 

Your wasting your breath. No way will some members here admit that a 3500# car taking a hard curve will be able to overcome 300# of inward thrust. Some of us drive these cars like the sports car they were designed to be. And, again what effect does 1/2" x 1" of ground up metal shavings and pieces of c clip mixed into your gear lube have on the bearings, races, spyder gears and ring and pinion?

 

same here, about 3/8" of play for about 35 years no problems here

 

I'm with you, i'll move on.....

 

Last attempt (seriously)

Do a bit of math and answer the question above as to why the inward force is 300 lbs and not zero and all will become clear.

 

As I've only spent the better part of my life (and income) flogging race cars and C3's, given this glaring lack of experience I guess I should concede that slip angles, lateral loads, sidewall oscilations and other such forces apparently don't exist equally througout cyberspace...