FLORIDA

My rear end is shaking -No not that one- differential end play. I have a 65 roadster with new rear wheel bearings and traing arms but I can shake the wheel and see the half shafts move in and out at the diff. I have removed the rear end and plan to disassemble tonight.
What is the allowable end play?
The suspension depends on this similar to the upper control arm - right?

Chuck Gongloff

Yes, it is similar to an upper control arm. Many don't think of it that way, but that's what it is.

Sounds like the ends of the yokes are worn. As they wear, you get more and more end play. Sometimes, they wear so much that they wear down to the grove where the "C" clip retains them.

Then the "C" clip falls into the diff, and usually gets ground up.

I can't give you a number as far as "allowable" end play.

I'll bet that when you take it apart, you'll find that the ends of the yokes/stub axles are worn WAY down.

Off the wall question. How is your rear camber? Can you adjust it to specs without bending the control rods?

Often, excess negative camber and the inability to adjust it is a dead giveaway to worn stub axles/yokes.

Post a pic or two when you get it apart.

Chuck

larrywalk

You'll be ok at up to about .090 of in/out freeplay on a side yoke; when it reaches that much, it's time to pull the diff and do some rebuilding.

No one likes the fact that there is no published limit, but at least the yoke is nearly always inward loaded. In fact some (not me) claim that they haven't used the retaining snap ring for years!

66since71

The end play looks and feels like a lot more than it actually measures. Before you start tearing it apart, buy or borrow a dial indicator and measure it. You'll be surprised.

Harry

FLORIDA

If retaining snap rings are not required then does that mean the end play does not matter due to the yokes always under a load from the weight of the car?

Chuck Gongloff

Yes, sort of. I've never seen a yoke pop out, although it might be possible if you got airborne, or maybe if you had the car on jackstands and the yokes were VERY worn.

Your end play question sorta goes back to what I posted before.

The stub axles/yokes and half shafts form the upper "A" frame of the rear suspension.

As the yokes wear, the entire assembly moves inward/medially.

That decreases the effective length of the upper A frame assembly.

That increases the negative camber of the rear tires/wheels.

That's why I asked you about the rear camber adjustment. A dead giveaway to excessively worn yokes is excessive negative camber that cannot be adjusted with the strut rods....without BENDING them to pull the bottom of the tire in.

Ever wonder why you see so many bent strut rods under the rear of Corvette's? They were not damaged in an accident, etc. They were purposely bent to enable more inward adjustment to compensate for worn yokes.

Chuck

Mike Ward

There was a huge discussion about this on the C3 board last year. What came out of it was that a car modified for autocross and driven under all-out autocross conditions could partially unseat a yoke affecting camber. A stock car driven under legal street conditions would never exhibit any signs, wheel alignment aside as Chuck mentioned.

Watch this video and make up your own mind:

http://www.youtube.com/watch?v=FIFZM...gnxkA&index=40

FLORIDA

That is great evidence of the system in action, serious action with heavy load.

TheSaint

Looks to me that the movement is at the wheel and not the diff.

MiguelsC2

excellent!!