C4 vs C3 differential side yoke wear differences?

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The Artist formerly known as Turbo84
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We're all familiar with the problem of C3 side yoke wear, and the resulting slop in the suspension, but I rarely hear anything similar when discussing C4 rears. Any reason for this? I've never had the need to pull a C4 rear apart, so I'm not up to speed on the design detail differences here.
 
We're all familiar with the problem of C3 side yoke wear, and the resulting slop in the suspension, but I rarely hear anything similar when discussing C4 rears. Any reason for this? I've never had the need to pull a C4 rear apart, so I'm not up to speed on the design detail differences here.

C4 has a upper strut, the axle floats in and out as necessary....as I recall it was a SLA setup, like C3 with the axle shorter than the strut....there are two arms going forward too, one on top, other from the bottom, diffy is tied to tranny with a strut running around/parallel to the driveshaft....there is a rear toe adjustment too, really simple, no shims....I forget it's location though....

I remember changing rear hubs on a C4 years ago....not so bad, really....

bolt in and not cheep, but at least a bolt in, no shims and play adjustments, all that crap...

:yahoo:
 
We're all familiar with the problem of C3 side yoke wear, and the resulting slop in the suspension, but I rarely hear anything similar when discussing C4 rears. Any reason for this? I've never had the need to pull a C4 rear apart, so I'm not up to speed on the design detail differences here.

C4 has a upper strut, the axle floats in and out as necessary....as I recall it was a SLA setup, like C3 with the axle shorter than the strut....there are two arms going forward too, one on top, other from the bottom, diffy is tied to tranny with a strut running around/parallel to the driveshaft....there is a rear toe adjustment too, really simple, no shims....I forget it's location though....

I remember changing rear hubs on a C4 years ago....not so bad, really....

bolt in and not cheep, but at least a bolt in, no shims and play adjustments, all that crap...

:yahoo:

Gene, what does any of this have to do with my question?????
 
The first line of his response was on topic. He just wandered a bit. :eek:
Because the C4 rear susp has an actual upper control arm (strut), the halfshaft doesnt have to be the upper control arm.
That keeps the side yoke from being driven into the differential cross shaft and being worn down.
 
We're all familiar with the problem of C3 side yoke wear, and the resulting slop in the suspension, but I rarely hear anything similar when discussing C4 rears. Any reason for this? I've never had the need to pull a C4 rear apart, so I'm not up to speed on the design detail differences here.

C4 has a upper strut, the axle floats in and out as necessary....as I recall it was a SLA setup, like C3 with the axle shorter than the strut....there are two arms going forward too, one on top, other from the bottom, diffy is tied to tranny with a strut running around/parallel to the driveshaft....there is a rear toe adjustment too, really simple, no shims....I forget it's location though....

I remember changing rear hubs on a C4 years ago....not so bad, really....

bolt in and not cheep, but at least a bolt in, no shims and play adjustments, all that crap...

:yahoo:

Gene, what does any of this have to do with my question?????

It does, kind of. Gene says C4 has an upper strut that takes the load off the halfshaft as being the upper suspension member. This is however not true, the toe link does not unload the halfshaft at all. When it comes to camber control the C4 suspension works the same as the C3 stuff.

The C4 stuff is parkerized on the inside (at least mine is, or it's something that looks like parkerizing) that will probably keep the wear down.


You do have a good point here, I haven't heard of C4 stub wear issues either.
 
I not so sure the toe control has no effect here.

On a C3, the lateral forces that compress the axle are from the lower strut rod pivot. This is directly in line with the lateral force on the tire.

On a C4, the same lateral forces (on the tire) cause a rotation that is countered by a diagonal line defined by the lower strut rod and the toe control rod. This diagonal line is not in line with the lateral forces acting on the tire (essentially horizontal).

Seems like the toe control rod has to be countering some of these lateral forces.
 
I not so sure the toe control has no effect here.

On a C3, the lateral forces that compress the axle are from the lower strut rod pivot. This is directly in line with the lateral force on the tire.

On a C4, the same lateral forces (on the tire) cause a rotation that is countered by a diagonal line defined by the lower strut rod and the toe control rod. This diagonal line is not in line with the lateral forces acting on the tire (essentially horizontal).

Seems like the toe control rod has to be countering some of these lateral forces.

Wouldn't that be only IF the upper/lower arms were not in line vertically/side view with the axle center???

:bonkers:
 
Wouldn't that be only IF the upper/lower arms were not in line vertically/side view with the axle center???

:bonkers:

Maybe I can explain it this way. Say you have a traditional upper/lower arm suspension as Gene describes. For the sake of the example, lets say the upper control arm is replaced with the toe control rod. In this example the upper control/toe rod would bear all the lateral forces.

OK, let's rotate the pivot center of this upper control/toe rod 10 degrees counter clockwise. Now you have the lateral forces acting on the tire (which are basically perpendicular to the road surface) transmitted through an 80 degree angle. Some of this compressive force is countered by the upper control/toe rod and some is countered by the axle.

A C4 toe control is rotated about 30 degrees from perpendicular? I don't have one here to look at but I speculate that (even at this greater rotation) the control rod is countering some portion of this lateral force.
 
Used (worn) C3 yokes

So, Got to thinking. Given this wear issue, are used C3 yokes just paperweights? I've got a few of them laying around from different rear ends (a couple sets with the HD caps), and I'm just curious what, if anything, to do with them outside of tossing them in my scrap iron pile.
 
I think some place rebuild them. They ad a tool steel wear end replacement insert or some such thing. I think if you find the place that does it they may buy cores
 
C4 has a upper strut, the axle floats in and out as necessary...

The side yokes are fixed in the carrier and do not float.The yoke end play is set by changing the thickness of the C clips used to retain yokes into the side gears.

C4rear-1.jpg
 
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C4 has a upper strut, the axle floats in and out as necessary...

The side yokes are fixed in the carrier and do not float.The yoke end play is set by changing the thickness of the C clips used to retain yokes into the side gears.

C4rear-1.jpg


Yoke endplay is set by shimming the clutch pack/spiders. The c clips can not be changed to a thicker/thinner size. That's a clean looking setup.
 
C4 has a upper strut, the axle floats in and out as necessary...

The side yokes are fixed in the carrier and do not float.The yoke end play is set by changing the thickness of the C clips used to retain yokes into the side gears.

C4rear-1.jpg


Yoke endplay is set by shimming the clutch pack/spiders. The c clips can not be changed to a thicker/thinner size. That's a clean looking setup.

Yes, it is clean....

with the upper and lower struts, I would see no reason for any clips of any type on the diffy yokes...why bother?? they not going to move outward, they not moving inward, but the cross shaft would stop it if they did....

so?? long as the splines where engaged on the side gears, WTF is the problem??

:gurney: I look at it like those silly spring clips on the end of the spline shafts of a FWD car, why bother?? the thing is bolted end into the front hub, and even there, 150 ft lbs of torque on that nut?? BS, I tap them down secure, put on the nut and tap that jamb flange into the axle shaft....been doing it that was forever now...never a problem....why would a RWD car with same essential arrangement have a problem..??
 
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with the upper and lower struts, I would see no reason for any clips of any type on the diffy yokes...why bother?? they not going to move outward, they not moving inward

The trailing arms are SLA , being rubber bushed they allow the upright / spindle to flex and change camber unless otherwise controlled.
If you have the suspension assembled without a halfshaft there is a lot of freeplay just pushing suspension by hand.

Across the car there is only the camber arm at bottom; the fixed length halfshaft performs the function of the top arm/ wishbone / link to maintain camber so it's movement must be limited.
Jag IRS pictured is the same setup

Jaguar_IRS.jpg


You are correct on FWD cars; the strut is fixed at the top , the bottom arm is fixed and the halfshaft cannot go anywhere.
 
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with the upper and lower struts, I would see no reason for any clips of any type on the diffy yokes...why bother?? they not going to move outward, they not moving inward

The trailing arms are SLA , being rubber bushed they allow the upright / spindle to flex and change camber unless otherwise controlled.
If you have the suspension assembled without a halfshaft there is a lot of freeplay just pushing suspension by hand.

Across the car there is only the camber arm at bottom; the fixed length halfshaft performs the function of the top arm/ wishbone / link to maintain camber so it's movement must be limited.
Jag IRS pictured is the same setup

Jaguar_IRS.jpg


You are correct on FWD cars; the strut is fixed at the top , the bottom arm is fixed and the halfshaft cannot go anywhere.

Don't you mean struts, upper and lower, somehting your diagram don't show...(I dunno jack about Jag rear ends, been way too long)....

the forward arms are indeed SLA, but no matter of the struts and that 1/2 shaft...the thing does not need retained in the diffy anymore than any FWD car, the way I see it.....

that pix, looks like what I remember a C4 as being...pretty close...strut on bottom, strut on top, the I see the ends of the forward arms/struts on the housing....NO??

:thumbs:
 
Don't you mean struts, upper and lower, somehting your diagram don't show...
I see the ends of the forward arms/struts on the housing ....NO?? :thumbs:

There is no top strut from the diff center to the upright on a C4 ; only the bottom camber arm and halfshaft.
C4 D36 shown but same setup

C4D36.jpg



The C4 rear is identical to the Jag pictured
 
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