Moving Rear Axle Back 1"

[sharon.schmidt]

Our 1973 Bronco project is moving along and we almost have the frame stripped. We are planning on uncut, stock looking EB with a 2.5" SL and possibly 1" BL if needed for engine clearance under the hood and 31x10.5R15LT or 32x11.5R15LT tires. We have some frame rust repair to do including areas around rear shock mounts and about 20" of rear lower frame on each side. Any other rust areas we need to look for that are common? Anyway, we are considering moving the rear axle back 1" to better match the uncut rear venders and hopefully better handling. Plan on using this EB for a daily driver, road trips with occasional fire road and trail use.

What are the advantages/disadvantages of moving the rear axle back? Clearance issues?

 

[garberz]

Avantage is, it keeps the tires from rubbing on the leading edge of the fender opening, when left uncut. And a little longer wheelbase is always good.

Mark

 

[JohnJohn]

Take a look at this 1" leaf spring block that can also be used to relocate the rear 1" or 1.5" forward or backward.
http://www.offroaddesign.com/catalog/Zero%20Rates.htm
I used it to get a cheap 1" lift.

 

[Scoop]

I'm using Zero Rates to get 1 1/2" in the rear. They work well. Not really typical "blocks" because they become part of the spring pack.

 

[hyghlndr]

Take a look at this 1" leaf spring block that can also be used to relocate the rear 1" or 1.5" forward or backward.
http://www.offroaddesign.com/catalog/Zero%20Rates.htm
I used it to get a cheap 1" lift.

Any pictures of them installed?

Thanks

 

[lonesouth]

Any disadvantage to moving the axle back?

 

[Dbarnes72]

And it looks just that much better when the tire is moved back and centered in the opening.

 

[duffymahoney]

Any disadvantage to moving the axle back?

You might need a new drive shaft. Depends on your lift etc...

 

[sharon.schmidt]

Thought this might require a new drive shaft but we are putting in a new drive shaft anyway.

 

[Crush]

I used the same thing but from diy4x.com. Their ez inch blocks also becomr part of the spring pack. The top edges are rounded so they dont pinch the spring. Plus tgey are ready to accept a degree shim(if you need this for pinion angle)so the shim becomes part of the spring pack too

This is it installed on the spring

 

[DonaldDouchebag]

Take a look at this 1" leaf spring block that can also be used to relocate the rear 1" or 1.5" forward or backward.
http://www.offroaddesign.com/catalog/Zero%20Rates.htm
I used it to get a cheap 1" lift.

I have them, too! They come in a 2.5" width which is a bit wider than the Early Bronco 2.25" wide springs so I ground the sides of the blocks down towards the ends where the u-bolts rest.

They bolt to the spring pack so they're super secure.

 

[Hopstr]

If you don't want to raise your rear end you can use the RuffStuff spring perches. Correct your pinion angle at the same time.

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

 

[bronconut73]

You can just drill a hole in your plate and drill a corresponding hole in your perch and bolt it all back together? The axle will be as far back as you drilled the hole.

That way you don't lift the back of your eb up with a block of you don't want the extra lift back there.

 

[sharon.schmidt]

Since we are having to replace the rear shock mounts anyway due to rust, considering the rear inboard shock hoop? Looks like it might be better to avoid future rust problems. Are there any clearance issues? Exhaust clearance?

 

[DirtDonk]

Yes, well, it depends.
Exhaust routing is always a concern on EB's, and adding the shocks and a crossbar mount under there just means you have to be more creative in that routing.
It's very doable, and many have gone that route over the last 20 years or so. You do need to at least consider the shocks and the type of use you'll put the Bronco too when going this route as well. If you are wanting to opt for the innermost mounting position so the more laid over shock angle can take advantage of all other long-travel aspects of the suspension, a stiffer valved or adjustable shock would be in order. Say a custom valved Bilstein or adjustable Rancho RS9000.
Or add anti-sway bars to your list of things to do.

Reason being the more angle you add to the shock, the shorter the shaft and piston move for a given amount of wheel movement. This effectively "softens" the shock and you will feel more body roll in corners and have less damping from a given shock. So stiffer can be better in this instance.

Not trying to talk you out of it actually. We sell them (http://www.wildhorses4x4.com/product/Rear_Inboard_shock_hoop) and they enjoy a healthy following of happy users. But there are simply things you need to be aware of when making certain mods. Many of the parts require modifying something else to make them work to their best. Might not be an issue for you, but stuff like that is always worth bringing up.

Paul

 

[DirtDonk]

Oh, and while rust is always an issue to keep an eye on, I don't see an inboard hoop as being an answer to rust. If anything, that location would be just as prone.
Simply painting things, keeping them in good shape, general maintenance (washing after snow runs or when driving much on salty roads), and just generally using the truck regularly, goes a LONG way towards keeping the rust at bay.

EB's had a big issue with windshield frames rusting to dust. But I don't know many who've ever had a replacement rust out. Not because they're treated or fitted any better (although maybe they are a bit?) but because most Broncos these days don't live the same life they used to. Once you spend time and money fixing something, you tend to not let it get that way again.

Rear shock mounts are one of those things. If you simply drive it in winter on salty roads and never rinse it with fresh water, you're likely to have anything on an EB rust through.
I guess where the inboard hoop style might have an advantage won't be that it's any less prone to rusting, but that simply replacing a mount bolt is a lot easier and cheaper than replacing an entire mount.
So you've got a point there for sure.

Paul

 

[.94 OR]

I measured and had a reasonably custom length rear driveline ordered. Once that was installed I realized I needed the 6° shim so now with the pumpkin rolled up the driveline is too short. Thinking of drilling the perches 1" to the front and remounting. Feasible?

 

[sykanr0ng]

For a stockish Bronco I would replace the original rear shock mounts with the same type.
No point going with parts made for more radical Broncos.

But you will probably need to patch the frame, it often rusts there because water and mud get trapped under the rear shock mount.

Best to set the rest of it up then measure for the driveshaft, that way you can get the right size the first time.

 

[sharon.schmidt]

When we got to looking at the frame and rear shock mounts, Ford probably could not have designed a better rust trap (top of frame, behind the fender, right next to underside of bed, out of sight, etc.). We live on dirt (muddy when it rains) roads and since this is a daily driver, we will not be washing it every time it gets a little muddy. Anyway, the inboard rear shock mount design looks to be able to shed mud and water better.