Lowering rear f100

[calvinstoy]

Has anyone out there lowered the rear of thier f100 using the last method described in tecnical section, lowering basics, where you basically flip the front mounting bracket, redrill the frame, and bolt it back down. And did you run into any big issues with tire and wheel combos after doing it? I want to get some 17" wheels but I found a great deal on a set of 20" wheels and tires from a 5 bolt dodge, I am going to look at an take some measurements to see if they will fit.

[FORDification]

Sorry about the delay in answering your post, but I was really hoping somebody with more experience (either first or second-hand) would chime in, but since nobody has....

I haven't done this, but after thinking about it, the only thing I can think of that might be cause for concern would be that the flipping that bracket around would essentially rotate the rearend housing, bringing the front yoke up. That in turn might cause some problems with the driveshaft angle. Of course, that could easily be remedied by removing the spring perches and relocating them, to rotate the mounting point back to a stock location.

That's about all I can come up with just sitting here looking at things. Here's a pic just for the visualization:



If you were low-bucking your project, this would seem the best way to go, since there would really be little cost involved....it would just be mostly labor.

[dragtruck]

I've lowered the rear on 3 trucks so far,the best way is buying the drop hanger(front spring mount ) from truckn.com it has 2 holes for different heights,this is the only part to buy if you have the flex o matic rear shackle,then you will have to cut the spring pads on the rear end and redo your pinion angle.If you don't have the flex o matic rear shackle then the same company sells drop shackles.Removing the flat overload spring will lower it 1/2 inch but you can't carry the same payload.We got 3-4 inches lower with just the spring hanger with flex o matic ,and I got 5" with the hanger and shackles on my 67.

[wt4speed]

I know how to measure pinion angle. My question is do I measure and record the current angle and record it . Then duplicate it after I make the hanger and shackel changes . Okay now I can almost see this comming the flex o matic shackel ? I'am asumming that this is the set up currently on my '69 step side (now lovingly dubbed the "stepper" by my office mates at work ,jealousy I would imagine) as I ive been around suspension for awhile and dont recall ever seeing this one . It has a slipper type bracket comming from the shackel kinda down under and back up and over the eye or main leaf . Am i even remotely close

thanks again
Tony B
DFW area
6mine9 a.k.a. "the stepper"

[FORDification]

Yes, sounds like you have the Flex-O-Matic, especially if it looks anything like this.



This is a before-and-after shot of the parts on my project truck.)

As for measuring the angle, I'm not sure I understand what you're asking, but here's a couple links to check out:

http://www.steeda.com/-techtips/pinionangle.htm
http://www.drivetrain.com/driveline_angle_problem.html
http://www.quickperformance.com/PinionAngle.html

[willowbilly3]

I know the drag racers tinker with the pinion angle some for launching but we basically always set ti the same as the front yoke, either the one one back of the tranny for the one piece or the middle yoke on a two piece.

[dragtruck]

You want to make sure the angle of the driveshaft is the same at the trans or the center bearing if its a 2 peice DS,and at the pinion.1 degree difference is ok.Also after your done make sure that the u-joints are in phase one a 2 piece DS.To do this,look at one of your DS and see how the yokes are lines up,the rear DS yoke need to be 90 degrees off from the front ones.The easiest way is to loosen up one side of the leaf springs,remove the spring pad clean it up,bolt it back together,do the other side,then loosen each side up and you can put a bottle jack under the pinion and rotate the rear end,then you can tack the pads to the rear .It might sound complicated but its not.

[willowbilly3]

I think you can get wedge shaped shims to adjust the pinion angle so you don't have to cut off the pad and reweld it.

[DuckRyder]

I think you can get wedge shaped shims to adjust the pinion angle so you don't have to cut off the pad and reweld it.

Yes you can! You can also in some cases shim the transmission mount to change the front angle.

[cobraF100]

What about flipping the rear axle and putting it on top of the rear springs to lower it 3" then it you want more use the 1" 2" blocks ???

[willowbilly3]

Do you only get three inches by flipping the rear end? It looks like it would be more like 5 inches.
(Note, "flipping" is just a loosly used term meaning put the axle on top of the springs. if you actually did flip it you would have 3 speeds backwards)

[calvinstoy]

By "flipping" the axle, don't you have to do the "c" knotch in the frame? Looking closer at it if you just flip the front bracket and redrill the holes the new holes will be very close to the old holes, possibly creating a "weak" spot in the frame. It looks like the way to go is the aftermarket front brackets. We want to drop the front 2" and then level the rear (3-4") at first. Then long term we want to do the 3" drop front axles and level the rear some more with both shackles and front brackets (5" drop)requiring the"c" to be added to the frame. Thanks for all the responses and thanks willowbilly the manifold is sweet!

[willowbilly3]

Glad the manifold fit the bill. Keep us posted and take pictures for us so we can see how to do it (or not do it )

[bryantracing460]

I did the rear axle "flip" on one of my trucks and didn't have to C notch the frame. I also think you come closer to a 5inch drop when doing this. JMO

[import600]

i want to try and take my 2wd f100 down about 2 or 3 inches how should i go about this? i want to lower the front and back. everything ive read takes it down about 5 inches and is really expensive. thats just to low for me, im a tall guy. so 2 or 3 inches? thanks guys