rear hanger flip

[1971ford]

Just ordered 4" lift superduty springs from pro-comp for the front.
The rear still needs to be fairly stiff to be able to tow so i figure it would be best to keep the stock springs on and save money too and just do a hanger flip.

I'm just wondering how much 'lift" this will give, how it will change the way the suspension flex's in the rear, and if the driveline angle is OK with this amount of lift. Do i need shims? really don't want to put a shim with the factory "block', not something i'd want to do.

From looking at it, it appears the hanger flip will give about 3" of lift, and shouldn't affect the driveline angle much. I'm not sure how it will flex differently by looking at it. Will it flex better, and will it hold weight just as well (towing).

THanks! Doing the front springs and rear hanger flip one week from today.

[averagef250]

How much lift depends how you do the shackle flip. Move the rear spring eye 8" and you lift the truck 4". The pinion angle will be wrong. The factory blocks are pretty easy to mill to the angle you need once you figure it out. Mill the axle side otherwise you get a crooked block.

I don't like airbags for several reasons, I need the beefed up stock spring plus the overloads. The overloads don't work at all with a shackle flip. I ran 8" blocks that I made from 2X4 .375 tubing with 5/8 B-7 U-bolts. Had to retorque the U-bolts every 6 months or so, the wheel hop was worse than stock, but not terrible, but no other issues besides that.

For the truck going back together again, I'm going to install a pivot/kingpin in each block with an anti-rotation bar on the axle housing. This will get rid of all the wheel hop, reduce suspension bind and get rid of the long U-bolts. It will add some maintainence to make sure the joint in the lift blocks stays lubed/tight, but that's not a big deal for me.

Something to think about anyway.

[fordman]

wouldnt a rear hanger flip actually lower the truck in the rear? unless you moved the hanger down.

[1971ford]

Nope, even if you don't move it down it will lift the truck up, i'm just not sure how much. At least 2", i'm guessing 3".
You can see how it works by looking at a rear hanger/shackle on your bump. All that really matters as far as lift goes is where the spring eye is. with stock configuration the spring eye is something like 1/2 - 3/4 the way up the side of the frame, if you flip the hanger so the shackle points down, the spring eye will be more like in the bottom 1/4 of the frame i'm guessing. I'd have to look at it again..
if the eye lowers 5 inches or so, then like Dustin said, split that number in half and thats how much lift it will give you..

[1971ford]

How much lift depends how you do the shackle flip. Move the rear spring eye 8" and you lift the truck 4". The pinion angle will be wrong. The factory blocks are pretty easy to mill to the angle you need once you figure it out. Mill the axle side otherwise you get a crooked block.

I don't like airbags for several reasons, I need the beefed up stock spring plus the overloads. The overloads don't work at all with a shackle flip. I ran 8" blocks that I made from 2X4 .375 tubing with 5/8 B-7 U-bolts. Had to retorque the U-bolts every 6 months or so, the wheel hop was worse than stock, but not terrible, but no other issues besides that.

For the truck going back together again, I'm going to install a pivot/kingpin in each block with an anti-rotation bar on the axle housing. This will get rid of all the wheel hop, reduce suspension bind and get rid of the long U-bolts. It will add some maintainence to make sure the joint in the lift blocks stays lubed/tight, but that's not a big deal for me.

Something to think about anyway.

what tool do you use to mill the blocks? I was thinking about this earlier, just shaving the block at an angle.... just can't think of what tool i'd use. I work at a very well equipped welding shop, but i'm stumped.
You say the pinion angle will be wrong with a flipped hanger, what do you mean "wrong"? Not driveable? just vibration/u-joint killing? or no vibration, but just going to have shorter u-joint life and seal life?

[averagef250]

With the block in a vise at the angle you need, mill your angle with a fly cutter, face mill, whatever you have. Cast iron cuts like butter. The blocks are as-cast on the sides so you may need to square them up first to grip them in a vise.

To figure the angle I use shims to get the pinion angle where it's needed then set the blocks on an angle parallel, sin plate or even as simple as figuring out how high one side of the block needs to be and using a shim under that side to hold it.

Pinion angle- You'll be rotating the engine spring/axle/block setup about the front spring eye bolt. There is absolutely no chance the pinion angle will be right. I't will probably drive around the block, but it'll be far from right.

[BobbyFord]

Measure the pinion angle before the modification, then replicate the same angle via shims.

[1971ford]

No fly cutter or face mill, or anything else like those tools that i can think of at the shop. Darn...

I assume a shim is drilled completely through so that the centering pin clamps the shim to the leaf pack? Am i right thinking it's not such a good idea to run a shim with the factory block or is it not that big of a deal?

[averagef250]

When you asked what tool to use to mill the blocks I took that as you saying you had a mill, but weren't sure what tool to use in the mill to do the work; My misunderstanding.

Steel shims work fine, aluminum ones do not. If you have a way to change the angle on the block you don't have to order the shims or wait for them to arrive or find they're not the right angle or worry about them failing down the road.

[1971ford]

AHh, well that was my bad then. No mill at the shop, I used the term mill in the wrong way.

Well i suppose for atleast right now i will just run steel shims. Check on them every once in a while just for kicks. I always look over my trucks periodically just to know things are where they should be..

[FordTruck]

I did the shackle flip on my old 69 and it lifted it a pretty good bit. If i remeber right I think I used 6 degree shims.

[1971ford]

Thanks for the info. Funny thing is I was using your truck as a reference as to how much it would end up lifting me.

I'm having second thoughts on flipping the hanger, afraid it will take away tow capabilities. The leaf will flatten easier, squatting the truck more, lifting the front more, all not good for heavy towing..

My buddy bought a set of i guess they'd be called add-a-leaf's, one for each side, they are about 1.5 thick if i remember right and are something like 7" long, they have a slight arch to them and are drilled through for use of a center pin. Basically a block, but safer.
Now i am thinking i will buy a set of those and put them at the bottom of the pack, and i will add a couple leafs throughout the pack as i have several 2.5" springs laying around. Should be able to get enough lift out of this stuff to match the 4" lift thats going on this weekend.


I'll still need shims though although if fordtruck used 6deg. shims i'd assume i would need something like 3deg? Because by doing a shackle flip it brings the rear of the leaf springs down, moving the pinion up. By adding more leafs then i'd need to bring the pinion up not down, but not by a whole lot. Guessing something like 3deg but i will check angles before and after.

[FordTruck]

Sounds like a plan..i don't know if it hurts towing but I do know it makes the suspension stiffer and the truck ride worse than an old dump truck

[averagef250]

Spacing the axle away from the springs doesn't change the pinion angle.

[1971ford]

To a certain extent though, correct?
So if i add maybe 2 leafs and a 1.5" thick add-a-leaf to the bottom, i won't need a slight degree shim?
That's nice..