Move axle back: Relocate Spring Perch?

[diggs00]

Thinking of moving my rear axle back 1". To do this I was looking at purchasing and relocating new leaf spring perches for the 9" diff.

I plan to go with WH 2.5 inch lift, 1" body lift in the future. Current setup is a 2" body lift with stock suspension.

RUFFSTUFF Perches:
https://www.ruffstuffspecialties.com/catalog/88PERCH.html

Question:
How do I get the correct perch angle on the axle shafts to meet the pinion angle needs of the future WH suspension?

This stuff is all new to me.

 

[Rustytruck]

2-1/2" lift usually doesn't need drive shaft correction and the fact the your moving the axle back even helps with the angle slightly. You will probably need a new driveshaft though with the combination of lift and distance. My 2-1/2 inch lift moved the driveshaft back some but didn't need a longer one. Its been going good for well over 20 years and the truck hasn't been babied off road. But my truck is an automatic, sticks can be trickier.

 

[hammer189]

I did this exact modification. I did the pearches 1 at a time to try and keep the angles I needed.
I cut 1 pearch off, then set the other axle pearch at 0 degrees. Then I set the new axle pearch so the pinion will be up about 6 drgrees when both are done. Tack welded in place. Removed other pearch and set the new one to be even with the other new one. Then burned them in. I read a bunch of comments here and 6 degrees seemed the average number guys came up with. I have no idea if it was correct because my truck doesn't move yet. Hoping for the best.

 

[garberz]

Set your pinion angle by welding the new perches on with the new suspension installed and the Bronco fully equipped. Cut the old ones off, clean the housing up, set new perches in place and install U-bolts. Set desired pinion angle, tack, disassemble and weld them up.

Mark

 

[DirtDonk]

Yes, don't guess.
Best to make the move when you are ready to do the springs as well. Don't modify it now, then drive the Bronco for an unknown stretch of time while the pinion is potentially mis-aligned for the stock springs.

You can set it up without the springs installed of course (by setting the frame and axles at the expected distance from each other of approx. 8.5"), but driving it much with the wrong angle would be counter-productive.

Either that, or expect to re-angle the new perches when the new springs are installed.
As Rusty said, it's not guaranteed that you'll need a new angle from now, but it's a very distinct possibility.

Paul

 

[Slednut10]

Make sure you get the correct width perches for the EB 2.25" springs

https://www.ruffstuffspecialties.com/catalog/R1991.html

https://www.wildhorses4x4.com/product/Anti-Wrap_Leaf_Spring_Perches/Bronco_Leaf_Springs

 

[Broncobowsher]

Put it together without welding, at first anyway. Weighted and finger tight U-bolts will allow you to spin the axle in the perches to get the angle you want. One it is correct for YOUR bronco, tack them, pull it apart and burn them in.

Fix the angle of the dangle before you think about a new driveshaft. Pinion angle changes scoot the pinion in and out as the axle rolls. What you measure with bad angles will be different than what you need with good angles.

 

[Scoop]

Have you considered using “zero rates”?

http://www.offroaddesign.com/catalog/Zero Rates.htm

 

[migs]

The easiest thing you could do right now is to drill a new hole for the locating pin in the existing perch 1" forward of the current hole, and don't forget to do the same to the clamp plate on top of the spring.
that will move your axle back and then you could wait to weld on new perches when you get new springs if it becomes necessary to address the angle.

 

[74BroncoCO]

My non-stock 9" spring perches already had a hole 1" forward. Easy as loosening things up, muscle the axle 1" rearward and tighten it all back down.

Here's some reading, particularly the stuff on the right side:
http://www.4x4wire.com/tech/pinionangle/

Or google proper setup pf pinion angle and pick your poison!

 

[Joe473]

The easiest thing you could do right now is to drill a new hole for the locating pin in the existing perch 1" forward of the current hole, and don't forget to do the same to the clamp plate on top of the spring.
that will move your axle back and then you could wait to weld on new perches when you get new springs if it becomes necessary to address the angle.

Good advice, I did this on mine with no issues. Just keep in mind combined with new springs with lift you may need to install shims to get pinion angle right. The benefit to this is you fine tune your pinion angle with shims let the springs settle and then burn in the new perches later at the correct settled in angle.

Sent from my SM-G960U using Tapatalk

 

[EB70]

I did the same thing. 2 1/2" spring lift, 1" integrated body lift. Bought the pads and assembled, measured, tacked. Pulled axle down and welded/painted.

No vibes at all with 37" tires. Drives great.

 

[Crawdad]

I did the Easy-Inch bolt on kit. Moves it back 1” or 0.50” you pick. You set these on the original perch locations. It also raises ur back end up 1” as well. I can weld but we’ll out of my league determining the angle and width of the dangle.

 

[Scoop]

I did the Easy-Inch bolt on kit. Moves it back 1” or 0.50” you pick. You set these on the original perch locations. It also raises ur back end up 1” as well. I can weld but we’ll out of my league determining the angle and width of the dangle.

Sounds the same or similar to the Zero Rates. The Zero Rates become part of the spring pack which makes them different than blocks.