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-   -   Rear spring shackle (https://www.fordbarn.com/forum/showthread.php?t=270927)

jhowes 10-15-2019 08:56 AM

Rear spring shackle
 

In rebuilding the rear axle, I replaced the shackles with new ones and the new sleeve bushings. I did not ream the bushings as they are already to large. You can now rock the spring back and forth (not in the car) a few inches. Any suggestions on how to repair this situation or is it OK the way it is? After all, the radius rods will keep the rear end where it belongs. Jack

Joe K 10-15-2019 10:04 AM

Re: Rear spring shackle
 

You don't tell us which car you have.

On the truck the 10 leaf spring is "tensioned" to the shackles. You have to somehow "compress" (and thereby extend the eyes) of the spring somehow (Victor Page in his book shows the spring compressor and blocks of oak and most today use a "spring spreader" - I have used blocks of oak and mass quantities of weight in the back of the pickup and a "bridge compressor" which is more akin to Victor Page's method)

But unsprung, the truck spring "pulls" the shackles together and out to perpendicular to the backing plates - not much movement there.

Under no load in the truck the shackles drop to about 15 degrees. Fully loaded about 30 degrees.

Other vehicles with lighter duty springs may be more "limber?"

Joe K

ryanheacox 10-15-2019 10:37 AM

Re: Rear spring shackle
 

The problem (or maybe not a problem) is that the shackle pin is maybe 7/16" and the bore of the bushing is over 1/2".



I installed those same shackles and was not impressed with the fit of the bushings but I've put a couple hundred miles on them and they seem okay. I've been toying with the idea of making an oil-lite bushing to replace the poor fitting one they come with.

rotorwrench 10-15-2019 10:47 AM

Re: Rear spring shackle
 

Something doesn't seem right with those figures since the fit would be too tight unless the bushing bore is reamed. The two parts should be close to each other in size. At least within a few thousands. Parts that are usually reamed for best fit are still relatively close in size to begin with . If not, the parts aren't made correctly or they are the wrong parts.

Joe K 10-15-2019 01:05 PM

Re: Rear spring shackle
 

Quote:

Originally Posted by ryanheacox (Post 1809842)
The problem (or maybe not a problem) is that the shackle pin is maybe 9/16" and the bore of the bushing is over 1/2".

Normal bushing reamers are 0.570 (A 14.5mm drill is commonly used for this as the fit is not precise) 37/64 (0.578) is close but if you're running small on the shackle 9/16 (0.5625) is the next smaller Imperial size.

The difference between a 9/16 shackle spindle and 14.5mm is only 0.008 which I judge a little generous but would work for this. 0.004 might be my preferred target.

The vendors ARE selling a "critchley type" adjustable reamer for this use to shave that 0.008 down.

Joe K

Floats 10-15-2019 01:15 PM

Re: Rear spring shackle
 

Hi Jack,
I have had the same problem, loose fitting shackles. On enquiring, the vendor replied that they are correct and that is the way they get them.
I was not impressed, however living on the other side of the world, I could not argue and decided to fit them regardless. I must admit, strangely they seem to be working fine.

ryanheacox 10-15-2019 01:30 PM

Re: Rear spring shackle
 

Quote:

Originally Posted by rotorwrench (Post 1809844)
Something doesn't seem right with those figures since the fit would be too tight unless the bushing bore is reamed. The two parts should be close to each other in size. At least within a few thousands. Parts that are usually reamed for best fit are still relatively close in size to begin with . If not, the parts aren't made correctly or they are the wrong parts.


You're right, I typed 9/16 and thought 7/16:rolleyes:

Patrick L. 10-15-2019 02:04 PM

Re: Rear spring shackle
 

It would have been nice to know just how much clearance there was. I don't think there is probably anything to worry about. They sound as though they should be loose enough to take grease easily. I've seen some come tight enough to fit but not accept grease.

Floats 10-16-2019 06:47 AM

Re: Rear spring shackle
 

From my post #6
If I remember correctly, I could put a match stick in one side.

jhowes 10-16-2019 07:58 AM

Re: Rear spring shackle
 

Mine sound just like Floats. You can put a match stick in between the pin and the bushing. My car is a 2-door 1931 with a leaf removed from the rear spring. Better ride??? Thanks for your replies. Jack

Patrick L. 10-16-2019 08:24 AM

Re: Rear spring shackle
 

That sounds like too much 'slop' to me even though I tend to like a tad loose. I think I would spin out new bushings.


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