How much (is too much) axial play in the side yoke if pulled and pushed away from and towards the rear diff. housing???
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Re: C3 .. side yoke play ??
Dale-----
In my opinion, .05" (or, ABOUT 1/16") is the absolute maximum end play that should be present. I've never seen a published GM spec on this although I've looked mightily for one. In any event, when you get to about the above-referenced end play it can very well mean that the stub axle end has worn and, most importantly, has worn through the case hardening. Wear after this point on the stub axle will progress very rapidly, so attention is needed to avoid "surprises".
To some extent, end play can also be induced by wear on the posi clutch pack. If this is the case, then that needs attention, too, so going into the rear end is in order.In Appreciation of John Hinckley -
Re: C3 .. side yoke play ??
Dale&Abigail...In Charlie Smith's rear end class at Bloomington, he indicated once you are around 0.030, it's time to address the clutch packs and/or the side yokes. His personal preference was to address it at 0.020, and he sets them up at 0.000 - 0.002, and they settle in to around 0.005-0.008. Both the clutch pack and the yoke end wear affect the end play....I happen to have a posi pack/case 4 series case he set up with new Eaton clutches, and it is at dead nuts zero play with new side yokes.....CraigComment
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Re: C3 .. side yoke play -reply??
thanks guys for the input and information .. sounds like you have led me to a winter project .. I guess I'll get out the heater for the garage out of storage . By the way can this condition make the rear a little "skidish" .. kind of side to side thing ??Comment
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Re: C3 .. side yoke play -reply??
You Bet!!!
It will corner like it is on "rails" when the camber is stabilized while bouncing around corners.
Hard to believe until you experience it yourself.
OldSlowVetteComment
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Beg to differ-
The inward force on the side yolks through the geometry of the rear suspension during normal driving is tremendous. The amount of side loading required to unload the yoke exceeds the traction capabilites of the tires. There's many people who run around with NO circlips holding the yokes in- (meaning unlimited side play) and experience no handling difficulties.
This subject has been bashed around recently- please check the archives.Comment
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Re: Beg to differ-
I wonder why Duntov had those clips put on????.... although he doesn't specifically mention the clips in his SAE paper discussing the design of the C3 chassis suspension.
I agree though, they are not needed under normal straight and level circumstances.
But........ how about going around corners fast..... and then add in an undulating pavement which begins to cause major body and chassis roll......
Hey... I don't want to argue about it.
Maybe the clips are there to keep the spindles from falling out during assembly, weren't the chassis put together upside down on the production line?
Anyhow, when I replaced mine, which were badly worn, there was a bigtime improvement in cornering performance. So my recomendation is still "you bet"
OldSlowVetteComment
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Re: Beg to differ-
I can tell you this much - Charlie Smith, world nenowned Corvette rear end rebuilder/specialist, made a believer out of me in his advanced class. He won't even use the current 0.055 clips that GM sells, he only uses the original 0.064" clips (Tom at International Axle has some nice ones too). The clip grooves are cut for the 0.064 thickness grooves. He won't get in a corvette with a yoke problem, and has known friends killed in high speed lane changes. Granted, there is a lot of inward pressure on the yoke ends, use your own judgement, but those clips are not there just for assembly...CraigComment
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A little common sense please-
Do a little math - figure out how much tensile force/shock load a .064" thick snap ring can withstand. Now multiply that by hundreds of thousands of cycles. = Disaster. Guaranteed failure.
No designer in his right mind would choose a snap ring set up to withstand such forces for even one cycle, never minds something both safety related and expected to last 100,000 miles or more.
Try to find any application on any car where tensile load is controlled by a snap ring.
If there were any tangible outward forces on the yokes:
1) why would GM not design a more secure arrangement, similar to a front or rear wheel bearing?
2) If the end play was critical to handling, why was there no effort to adjust/control it during original manufacturing or service?
My belief is that only time there is zero or negative load on the yokes is when the rear wheels are off the ground- GM put the snap rings there to facilitate assembly of the car, and to prevent the yokes pulling out during routine tire changes etc.
This subject reminds me of the rotor rivets legend.........Comment
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Re: A little common sense please-
Mike - clearly, the snap rings are not intended to control massive amounts of outward force, rather, to secure the assembly. The issue Charlie had with the 0.055 vs 0.064 snap rings was that they allow end play in the yokes even when the clutch packs are shimmed correctly. By the way, GM DOES have end play limits in the overhaul manuals and they do worry about this play. He also feels GM's 3 link design is weak, that's why there are 4 link setups that can be used for racing, that do provide positive control of the suspension without relying on snap rings to control outward movement. He gave 3 or 4 stories of his friends being killed by vette yokes being worn out to the point where the snap ring had fallen off inside. Jungle Jim Lieberman was killed in Chicago in a lange change problem caused by squirley handling on worn out yokes. Anyway, everyone has the right to thier opinion, I do understand that normal driving conditions is forcing the yokes against the center cross pin in the posi case almost always. But if you are going to throw your car into some fast maneuvers in an autocross course etc, and there are some bumps that could cause the rear to lighten up, why risk it? I have been on autocross tracks and seen one whole side of the car in the air do to corneing G's...I wouldn't want that snap ring missing. If you want to debate him on this point, feel free, I am just relaying his key message from the class, that he felt so strongly about to make the point over and over....for others to consider and use their own judgement. He has torn apart over 8000 rear ends and I guess I feel he knows his stuff, and does extensive racing as well. If you just cruise around in your vette and never drive it har, you can probably feel safe, but, if you ever need to make an evasive rapid move to avoid a collision, why would you not want to have some margin of safety. By the way, the rotor rivets is different...the rotor is held in place by the wheel and lug bolts, not at all the same...flame away if you wish, and I can email Charlies phone number if you want a heated debate with him! CraigComment
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Re: A little common sense please-correction
I will retract my statement about the overhaul guide giving these end play limits, that was from my notes for Charlies class. However, it doesn't negate the importance of insuring the yokes are not worn through the case hardening. The key to the end play is to evaluate how much of the case hardening is left, as when it wears through the yokes wear very fast, then the snap rings fall off. Sometimes they wear so badly that the yoke begins to rub on the differential carrier casting....CraigComment
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Re: A little common sense please-correction
Go get um Mike. I`m with you. But I`m also tired of arguing the point.Comment
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Re: A little common sense please-correction
This seems to be a very highly debated issue ... very interesting reading .. everyone has valid points and I thank all of you for your inputComment
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Re: A little common sense please-correction
Hey guys....peace! I was only trying to convey a message that was drilled at me in a BG class. So help me see what I am missing, if I recall my physics correctly, there is a primary moment of force upward that the leaf spring is counteracting downward to support the car. Then there is the inward component of the force based upon the pivot fulcrum where the strud rod connects to the spindle support, and the halfshaft counteracts that rotational force and keeps the spindle support from rocking inward. So part of the upward moment is transferred inward againt the yoke. So say the car is 3000lb, for kicks lets say it is divided in 4 so one rear corner supports 750lb. Given the 3 link concept, with the primary vertical weight transfer being handled by the spring, it would seem the short arm leverage distance of the spindle support would only be transferring a small part of the force inward...maybe 100lb or less....not tons of force. Please don't take this as an argument, I am just trying to understand why you think this force is so large that an abrupt side force outward on the yoke in a cornering action would not allow the yoke to pull out of the carrier....and sorry if I have created a holy war, this sounds like one of my college engineering physics classes from 25 years ago!...thx, CraigComment
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Let's move on to more interesting stuff-
who's up for a debate on:
synthetic oils
pertronics ignition
DOT 5 brake fluid
SS fuel and brake lines
NCRS bashing on the CF forumComment
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