Moving rear axle back

[honeycoon_]

Hi everyone, I would like to get some bigger tires (33s) on our uncut Bronco. We currently have a 1" body lift and a 2.5" suspension lift on 31s. I would like to avoid grinding off and re-welding where the leaf springs mount to the body, as I would like any change I make to be reversible.

Has anyone used an offset block like this one before? What is your experience? Did you use this exact product or something different?

Another option we are considering is shortening the rear axle just slightly. Any experience with this as well? Is one better than the other, or is a combination best? Thanks in advance.

 

[DirtDonk]

Should get lots of good answers to that one. Lots of different ways, but I bet most have used the block. There are the blocks, new perches with multiple hole locations, even drilling a new hole all the way through the spring packs (instead of, or in addition to). But that latter one does not get used often I think because it's a pain.

When you say shortening, it sounds like you want to narrow the whole rear end to tuck under the fenders more?
A lot of work, but very doable and probably has been done. Though not often here I don't think. You need to remember that the inner wheel tub is also part of the equation, so would come into play. More so if you have wider tires, or are planning to go off-roading a bit where you twist up the suspension. Even with the stock width you can rub the inside of the tire on the wheel tub.

Good luck!

Paul

 

[honeycoon_]

Should get lots of good answers to that one. Lots of different ways, but I bet most have used the block. There are the blocks, new perches with multiple hole locations, even drilling a new hole all the way through the spring packs (instead of, or in addition to). But that latter one does not get used often I think because it's a pain.

When you say shortening, it sounds like you want to narrow the whole rear end to tuck under the fenders more?
A lot of work, but very doable and probably has been done. Though not often here I don't think. You need to remember that the inner wheel tub is also part of the equation, so would come into play. More so if you have wider tires, or are planning to go off-roading a bit where you twist up the suspension. Even with the stock width you can rub the inside of the tire on the wheel tub.

Good luck!

Paul

Thanks Paul. Yes, I meant narrowing the width of the rear axle. How do people alter the inner wheel tubs? I'm looking at getting 33x10.5x15s if that helps at all. Would like to go with the blocks if they are a solid option, as they seem the easiest as well as the most "reversible" option.

 

[chuckji]

I’ve also considered using these on my LUBR.
One thing to keep an eye out for, I believe these blocks are wider than Bronco leaf springs so you might need to machine/trim them down to fit between the U bolts.

 

[Revelation]

EDIT:
Just saw the update where you want to narrow the axle. That will require not only the axle tube to be narrowed by cutting off the outer, narrowing the tubes and welding on new outers. Best to have that done at a shop that can ensure alignment is correct then you will need the axles narrowed.
As for the wheel tubs, just have to add an inch or 2, But that will do away with the factory rear seat.

 

[mp]

I have used that exact product with great success. I have 31’s on an unlifted, uncut bronco.

 

[honeycoon_]

EDIT:
Just saw the update where you want to narrow the axle. That will require not only the axle tube to be narrowed by cutting off the outer, narrowing the tubes and welding on new outers. Best to have that done at a shop that can ensure alignment is correct then you will need the axles narrowed.
As for the wheel tubs, just have to add an inch or 2, But that will do away with the factory rear seat.

Ideally I don't have to narrow everything. The blocks would be my first choice.

 

[DirtDonk]

If you keep with the narrower 10" wide tire theme, you should not have to modify the axle. As long as you put those tires on wheels that have the proper backspacing that is.

Paul

 

[DirtDonk]

I like my wider blocks. In fact, I might now do this to my '68 when it's time for tires next time. The gearing is perfect for off-roading, but a bit short for the street so taller tires would be a benefit. And look good too!

My 1" blocks on the '71 were just a hint wider than the springs and I was also up-sizing to 9/16" diameter u-bolts. So I filed notches in them where the shanks of the u-bolts traversed the blocks so they had nice pockets to ride in.
Back then I had no fancy tools or skills, so I just used the round side of a half-round file. Worked slick as all get out since the blocks were just cast-iron.

Paul

 

[Hinmaton]

I have a set of these on my truck, stretching my wheelbase to 95”.
They work really well, but they are designed for wider leafs with shorter leaf stacks, so I had to buy longer bolts.

Sent from my iPhone using Tapatalk

 

[904Bronco]

I bought that block for my 69 Project... "Mater"

I have a 2.5" lift and decided to go with a block so I could set the housing back... Best laid plans...
With a degree shim thrown in the mix, which required a longer centering pin, it just looked to "Rigged" to me. An accident waiting to happen. So I used it as a lift block for now.

A better way to go, In MHO, would be to replace the perch on the housing with a longer one... With different pin positioning points.
I see it working well with a stock suspension though..

 

[gnpenning]

That block looks like a great addition to the front of my plow truck.

 

[.94 OR]

I changed perches on mine so I could get the rear offset and turn the pinion up to match my lift at the same time.

 

[hammer189]

I used these. Very happy with them.
https://www.ruffstuffspecialties.com/R1991.html

If the truck is together, you can figure out if you need to adjust the pinion angle before you take it apart.
These are a much bigger contact area than stock.
The old perches are easy to cut off with a grinder.
I cut 1 side off at a time. Set the old side at level and then tacked the new side at the corrected pinion angle using a welding degree gauge. Cut the other one off and made sure the 2 were level when tacked. Burn in and paint. Easy, and I am a crappy, self taught welder.
I never noticed until much later but some broncos rear axles are not even left to right. If yours is off you could correct it at this time by moving the perches left or right.
Mine is about 1/4" off to one side.
Good luck, David

 

[Broncobowsher]

Few thoughts...

Gave up on shifting the axle back. There is a crossmember right behind the housing. Any significant push back would put the axle into the crossmember.

As for narrowing the axle, you can generally get away with different offset wheels to accomplish the same thing. Spend some time studying width and backspacing.

Not any good way to go wider and keep an uncut fender. The street rod market has a ton of wheel tubs that can be spliced into your muscle car. Trouble is the Bronco frame is right there.

 

[rguest3]

Yep. Ruff Stuff. They have the Spring Perches (Great for anti axle Wrap) and the Top plates both with 3 Holes for adjustment.

 

[Crawdad]

I used the same kit (EZ-Inch) from your first post. I moved it back one inch, not the 1.5”. You will need longer u-bolts. Be mindful of the driveshaft you have might be too short. Look at post 95 and you will see my install https://classicbroncos.com/forums/showthread.php?t=229232&page=7 .

 

[honeycoon_]

Just found this new product from James Duff: https://dufftuff.com/product/lubr-lift-block-axle-alignment-plate/. It shifts the axle back 1.25". Probably gonna get these, as they are made by Bronco people for Bronco people.

 

[eb-nutt1]

Just found this new product from James Duff: https://dufftuff.com/product/lubr-lift-block-axle-alignment-plate/. It shifts the axle back 1.25". Probably gonna get these, as they are made by Bronco people for Bronco people.

I wonder what the thickness is on these? Kinda in a similar situation, and was about to order spring perches from Tom's with the 1" fore/after holes relocate...already have 2.5" rear springs and don't want any more lift height with it being a half cab.

 

[honeycoon_]

I wonder what the thickness is on these? Kinda in a similar situation, and was about to order spring perches from Tom's with the 1" fore/after holes relocate...already have 2.5" rear springs and don't want any more lift height with it being a half cab.

I believe they're 1/2". I believe that the dimensions they have on the page are wrong. I called them today and they're going to check and give me a call back with the dimensions. I'll post here when they do.