Has anyone ever done a rear shackle flip to lift the rear of these trucks?
Mine's a 76 f100 and I would like to get rid of the factory blocks and maybe lift the rear a couple inches. I don't have a much money right now, so I wanted to see if you guys could give me some ideas on a diy shackle flip. Thanks.

 

hey dave...

the reverse shackle flip is pretty straight forward..jack up the rear, cut out the factory rivets (blue wrench and a hammer drill work best)...be sure to use grade 8 bolts to put it back together....I did mine in a couple of hours...be sure to get new shocks for the back too...you'll see why.

Good luck!

~grizz

 

If you use your existing hanger, you need to be aware of the shackle angle after the flip. It is recommended that you move the hanger foward slightly to obtain a 6 to 8 deg angle. By bolting the hanger on the opposite direction the shackle will be facing slightly foward, and suspension extension will be greatly limited and the ride will suffer.
By using a stock rear hanger, you will obtain around 2.5 inches of lift and this is usually not enough to eliminate the block.
Consider a kit, or consider using a hanger like the one found at the front of your rear spring. Using a hanger that will locate the shackle mounting point lower will net over 4 inches of lift and allow you to eliminate your block all together.
Look at the front fixed hanger at the front end of your rear spring, and imagine using an identicle hanger for your flip. This means that you will purchase a set of hangers that are identical, and use them at both ends. The front hanger will allow a great deal of lift
I also saw another post where you asked about the weight capacities, and the reason you loose capacity is because of the weight that is spread over a shackle in a tension, vs. compression design. The strength is in the shackle and not necessarilly in the hanger. Too much of a load, and the compression shackle will fold sideways.

 

It will move your axle ahead some in the fender well. It doesn't hurt anything but personally I don't like the look so I droped my front hangers down. I would make sure your slip joint is in good condition and is in far enough as well.

 

so bassicly all you do is torch out the 4 rivets on the leave spring hangers and turn them around? and then just run grade 8 bolts in place of the rivets?
thanks
Mitch

 

not turn them around flip them over....

but yeah.

Off road design has some spacers that give you 1" of lift but will allow you to move your axle back 1 1/2" in relation to the leaf spring center line. This will correct the tires moving closer to the front of the wheel opening.
http://www.offroaddesign.com/catalog/Zero%20Rates.htm

 

so if your standing on the drivesr side a the truck looking at the hangers. the left hangers goes to the right and the right hanger goes over to the right?

or do you keep them in place and turn them upside down?

or do you do the switcharoo and also turn them upside down?

lol sorry im dumb
thanks
mitch

 

I think you just flip the hangers over, no switching sides. I've got an 88 f250 parts truck could I use the rear spring/ front hanger to make the flip/drop to get the stock blocks out of there? Would I still have to drop the front to get the wheel centerline back in the middle of the wheel well? Does anyone know a way to beef up the stock shackle to maintain the weight raiting? Sorry for all the questions just trying to do this right, but cheap.

 

Guys:
just performing a shackle flip does very little to move the axle foward.
The axle centerline, and the front spring bolt remains the same. It only becomes a pivot. It would take about 12 inches (or more) of additional drop on the rear of the spring to make any real difference whatsoever.
Pinion angle is affected far more than the wheel base is. Since you are only lifting one end of the spring, the pinion angle will change with more drop at the rear of the spring, and the actual wheelbase will remain unchanged (within reason).
To make a major impact on wheelbase ( to make the axle move foward) it would require much more than a few inches of lift at the springs shackle end.
Understanding the difference between a compression shackle, and a tension shackle will resolve all of the questions above.
Now open a discussion about which design offers greater articulation, and the plot will thicken.
I believe while my 64" rear springs flex rather well (with a compression shackle), the short shackle actually limits articulation! I believe I can create far better results by going back to an inverted shackle design (like factory) and a long spring with a crazy long shackle.
Nice long progressive spring with a tension shackle (super long) should provide many, many inches of travel without a block, and with little requirement for any additional traction devices.

 

Well now I'm going to have to disagree ;-). Well, not entirely, but I'm sure you can get better suspension travel with a shackle in compression. Especially if you have arched leafs and you use somewhere around a 30-45 degree angle on the shackle (mounting the fixed portion of the shackle leaning towards the center of the spring).

This allows the shackle to work with the spring as it elongates or shortens. As your axle droops, the spring will bend more, causing it to shorten. This pulls the shackle down as it pivots enhancing droop. When the spring compresses, it flattens out and pushes the shackle back and up, enhancing compression. It also makes for a MUCH softer ride. So in some respect, you can adjust your ride softness by adjusting your shackle angle.

 

Wouldn't using a super long shackle in this confuguration actually lower your truck. You may get some wicked articulation but you could only fit stock Yugo tires on the truck.

 

Slow:

in another thread you posted a pic of your shackle hanger set up and it looks like its mounted with the shackle and hanger in a vertical position. Is this just the angle of the picture or is this how you had it set up? You mention angling the hanger to get the proper shackle range of motion, what kind of angle are we talking about here? Could you also leave the hanger verticleand just mount it forward an inch or so to get the angle you want? It seems to me the compression shackle is the best way to get the articulation and lift out of the rear suspension. The tension shackle seems like a heavier duty setup that will reduce some of the side loading and lateral flex you would get from the compression setup. Am I wrong here, or is my reasoning good on this one?

 

Yeah, I probably should have been a little more specific. In stock configuration it would be pretty low, but with very low mounting point it could have a rather long tension shackle and would work (in theory) better than the compression shackle. I have considered that clearance might be an issue, but not any more than a similar compression design.
Desert racers are using this design, and able to obtain mad travel numbers that can easily be utilized by us in a different application.
Even toyota and ranger guys are converting from factory compression to a modified tension style (exactly the opposite of us) to obtain better wheel travel and control. Even the leaf sprung trucks have a ton of travel.
By applying these concepts to a large truck, I believe I can still obtain a happy medium between stability, strength, travel / flex.
My compression set-up with 64" rear springs work very well, and they ride great. They flex like crazy (although I do kill bushings) and while the payload is limited, I feel that I can install a spring with even more arch and have less pre-load (so the spring becomes rather flat while under just the load of the truck empty) and the longer shackle will allow for far greater droop with less possibility of the shackle flipping "over center" which is so easily done with a compression style shackle.
See most aftermarket kits have a stop to prevent this, which limits the overall travel of the vehicle.
I like the compression conversion, I run one myself, but I have found, and reached its limitations, and believe there is a much better design, that has greater capabilities, and addresses some of the issues that we have run into with our compression style conversions.

 

So were you thinking something along the lines of droping the shackle hanger 3 or 4 inches and making the shackle 3 or 4 inches longer. I think this would maintain stock height and allow for the suspension travel you're talking about. I'm still not sure if you would get that much more articulation out of a setup like that. Please explain to me how the compression shackle is capable of more travel.

 

Yeah actually I had the idea of getting a little more nutz than that. Actually I have them on one truck already. I am waiting till the project comes a little further along, before I update my gallery, but if you would like to see what I am talking about feel free to PM me with an e-mail, and I will be glad to send you a couple pics.
You know what they say, a picture is worth a thousand words, lol.
I have tested it with a forklift and such, and it seems to work, but I have not driven it, or tested it yet. Should work, but there is still a little doubt.
I will look for your Pm.