74 EB Sandrunner under development

[sstlaure]

Trying to figure out my rear shock tie-ins, the tops will be essentially even with the hoops that are parallel to the top edge of the body tub. (@ 26" fully compressed in length. the shocks will intrude ~19" above the floor inside the body)

 

[sstlaure]

Shackles at full extension. I'll be going with 12" Travel front/16" travel rear King Bypass Shocks. Still trying to dial in the ride height. I'm thinking I may lengthen the shackles, but that would lower the rear ride-height a bit with my current springs. ?:? Not sure if I'd like it sitting a$$ low or not...

 

[sstlaure]

Still trying to figure out the cleanest method of tying the shocks into the cage. I'm going to add (2) more pads at the floor that are tied into the frame at the hoop going behind the front seats (where the rear seat fore/aft tubes tie into the main hoop.

 

[broncobsession]

Looks good. I've got 2 questions: where did you get the 78-79 radius arm brackets? and what bushings did you use to correct caster after installing said brackets? thanks

 

[Unregistered]

Can you explain the purpose these bushings serve?

I just mounted my cage to the body I still need to tie it to the frame... still time to make some changes... Does this allow a little flex so things are not so rigid?

-Ed



They're polyurethane suspension bushings from a late 70's Mazda RX7 (I think rear suspension). They are sleeved into 1 3/4" dia X 0.120 wall DOM tubing. I used 3/16" thick steel for the tabs. I believe that we got the bushings from Energy Suspensions. Give them the size details and they can give you the right part #.

 

[sstlaure]

Can you explain the purpose these bushings serve?

I just mounted my cage to the body I still need to tie it to the frame... still time to make some changes... Does this allow a little flex so things are not so rigid?

-Ed


The bushings serve to isolate the body from vibrations transmitted up through the chassis. (Similar to the polyurethane body mounts.) I just helps the body from getting tweaked during body flex. We jump our trucks a ton, so we want them built to take it. It's especially critical on my truck as I have the lightweight race Mallot body (has virtually no reinforcement, but it's super light)

I just found one of the boxes from the bushings, so if you want the part number for the bushing (fits perfectly inside 1 3/4" x 0.120 wall tubing) I can post it. Energy Suspensions makes it.

 

[sstlaure]

Looks good. I've got 2 questions: where did you get the 78-79 radius arm brackets? and what bushings did you use to correct caster after installing said brackets? thanks

Got the radius arm brackets from some guy in Florida (He had some junk 78-79 parts, and I've got access to a blast cabinet) I think I paid $35 or $40 for the pair. I posted a wanted ad on brocograveyard.com.

I believe I used the 7.5 degree kit from JBG. My suspension was raised 5.5", but then the rear rad mounting point was lowered ~3", so the net effect was a 2.5" change with respect to the radius arm/axle position. It seems to be about right.

 

[Unregistered]

I think your bronco will be ready for "x sports" once completed.

I too have a fiberglass body (kentrol) and will be taking it out to silver lake from time to time. I do not think I will be using it as you are planning but... since it is fiberglass would you recommend this as the preferred method of tieing the cage into the frame to avoid problems... Even in builds that are not as extreme.

I am familar with the glass body you have. I also owned one, do you have the one piece front clip? Is it set up to easily remove the entire front end?

Please post the details on the bushings...

-ED

 

[sstlaure]

I've got the separate fenders/hood/grille. Hood is held on with pins. I'll have to post the bushing details on Monday as I'm heading out of town tonight. You can see how we treat our trucks at the dunes at the attached thread.

http://www.classicbroncos.com/forums/showthread.php?threadid=47784

As our shocks attach through the floor to the cage, we've got a ton of load going through them, but the isolators would definitely help with any cage tie-in. (Make sure you lube the bushings to keep em from squeaking.)

We'll for sure be at Silver Lake over Labor Day this year if you want to check it out a little closer.

 

[Unregistered]

!@#$

Thats the only thing that came to mind

I want to witness that...

-ED

 

[sstlaure]

The bushings are Energy Suspensions Part # 11.3103G It is a Mazda Rear Control Arm Bushing, replaces the outside pivot bushing. Applications include 86-91 Mazda RX-7 (and cage tie-ins)

 

[77bronco_ed]

Have you done any more work... Keep us updated.

I am taking notes

 

[probaja]

pics

We needs more pics!!!!!!!!!!!!!!

 

[sstlaure]

Shocks and bumpstops are in the garage, fabrication will start up after Labor Day (no room in the pole barn at the shop to get the Bronco inside.) I'll take pics of the shocks and bumpstops and post them Monday.

 

[sstlaure]

Took some quick pics...Here are the shocks and bumpstops

 

[sstlaure]

Rear shock location (approximate, the shock body may or may not stay completely inside the body.)

 

[sstlaure]

16" Travel rear shock...Fully Extended 44" End to End.

 

[77bronco_ed]

sstlaure,

Just trying to follow along. ..
to re-iterate
expecting 13" vertical travel F/R from both axles basically targeting fro 80% of what the awesome green machine can do.

Modifications from stock suspension to date:

5.5 susp lift ...
National leaf springs and coils- target (130 lb/in) (rear mounts repositioned?)

*shackles modified?

*changed radius arm brackets to brackets from a 78-79 Bronco

*7.5 degree kit from JBG
*added cage “tie ins”-

*King Bypass shocks and air bump stops (how are you determining the position required?)

Any critical information not posted that would help those that may want to duplicate your suspension? key measurements for positioning?)

Thanks,

Ed

 

[sstlaure]

The latest plan (most accurate so far) has 12" front travel/16" rear. (5.5" susp lift, 2" body, I'm going to cut the fenders larger for more tire clearance)

FRONT
The front will use a 14" travel shock mounted in front of the coil to achieve the 12" travel (Still need to figure out exactly how I want to mount the bottom end to the radius arm, probably some bracketry on the clamp end of the rad arm) Used basic Trig to calculate the shock length based on travel. (If you need more info on this, let me know). Stock radius arms, 78/79 drop brackets, 7.5 degree bushings (still not sure about the caster, may need further improvement, still looks kind of steep). The arms don't seem to bind up the way they did in the 66-77 rad brackets. Top mounts will be custom hoops w/cross brace across the top of the engine

REAR
16" travel shock mounted straight on top of the spring perch (I'm probably going to machine something cool for the u-bolts and lower shocks mounts to be on...we'll see) The upper mounts for the shocks are in the roll cage, with the shock passing through the floor. I'm going to make some kind of center mounted single ladder link to control axle wrap.

Brett from King said that as long as the shock can bottom completely out, then they will perform correctly, so bottom out the susp. bottom the shock, and bottom the bumpstops, set this as full compression and work backwards from there.

In my case, I'm going to pull the leaves/coils to set the susp at full compression, because the rear axle will follow the radius of the ladder link and stay in the proper position. you could probably ratchet strap the suspension down, but be careful releasing the tension if you try it that way...(unfortunately speaking from experience %)%) Stupid strap.


Just for giggles...If a person were to offer a suspension system similar to what I am building...what would people be willing to pay for it??? It would include.....

> King Bypass Shocks/airbumps ($3K retail for shocks/bumpstops)
> Full cage tie-in to frame 6-8 pts (needed for rr shock mounts)
> Custom cage or fabricate mounts into existing cage
> Vehicle would have to be 2 or 3 seater.
> All tubing would be raw/unpainted 1 3/4" x 0.120 wall DOM

Got some funny ideas floating around in this head of mine. The way this truck is designed is a ton easier to fabricate than the green machine, we may have a marketable product if there is enough interest...(need good insurance for this kind of thing, that can't be cheap...people will do some seriously stupid things then blame everyone but themselves...)

 

[77bronco_ed]

It will be nice to see the comparison from the two different trucks....

I am thinking that once you get a chance to test it you may also come across a few minor things that you may like to have done differently or may even make adjustments to refine your plans.

How does this travel compare to stock?

Is the travel key? for the ability to handle the whoops and landings from the air born jumps? Does this soften the landing?




Thanks...