Duff's monster 4-link install *PROBLEM*

[chuzie]

Affirm on the 2" of body lift.

 

[bluesbish]

I know this thread has been going for a long time now, but I just wanted to add that I was looking into this kit about 4 years ago. I think at that time it had not been out too long. I called duffs and had about a 10 minute conversation with them about my rig and this rear suspension system. They told me flat out that they do not reccomend this system for rigs that will see highway driving above 45mph. That was the end of the conversation and I never thought about it again untill reading this thread today. just wondering if this is still what they are telling customers interested in this system.

 

[fdezone]

I noticed this "chris" dude also experienced issues back in '08. Have you tried PM'n him to share stories?

Hard to compare with the rigs SpareParts posted since they're not 9" applications.

A few differences of note between yours and Chris' (most comparable):

1. Used adjustable coil buckets (greater coil stand-off on top).
2. High-clearance lowers with bushings at axle vice heims (both sit above the axle).
3. Only 2 "Rancho RS9000" shocks (those 4 linear shocks look ridiculous).
4. Lower shock mounts sit lower (mid-line on the axle tube).
5. Shocks angle more towards the center than forward (as they appear in pics).
6. Upper shock mount tube is raised in the center (body lift dependent).
7. No bump stops, limiting straps or sway bars on either.

chuzie

chris (http://classicbroncos.com/forums/showthread.php?t=131871)

chuzie

chris (http://classicbroncos.com/forums/showthread.php?t=131871)

Not sure that helps, I just feel for you brother.

 

[chuzie]

They told me the same thing about the highway driving. Basically they do not recommend it but they drive theirs on the highway. I think it more of a liability issue so they need to cover themselves and I completely understand that.

Initially, I had to relearn how to drive my rig as I had an extremely stiff suspension prior to the conversion. The first ride around the neighborhood, I thought I was going to roll it over or something due to the large amount of lean that I was not accustomed to.

Well, the rig was not going to roll; not even close. The days of going around corners at ridiculous NASCAR speeds are over. I have had the rig at 90MPH on the interstate. I feel it is stable and I am comfortable with it. I have made high speed maneuvers and felt safe but wish I had a sway bar installed in the rear. Don't get me wrong, if you act like an idiot you are going to bite it. A sway bar should have been part of the kit although I understand the difficulty involved with including a universal sway kit. I think the Rodeo sway bar setup is the best way to go in terms of universal applicability but I have not installed mine yet.

Thanks for the pics of the other rig. Definitely some food for thought. Hope it will give me some direction for a solution to some of these issues. I have not contacted him but certainly will.

 

[blazinchuck]

whats up with the bent links?? was that another option or the 1st design?

im diggin the inboard shock set up with rancho 9000! looks cleaner

 

[SOLID1970]

I have been following along as I have not had a chance to get under my bronco due to my work load. I will probably get to it next month but I am just curious what my next move should be? The 4-link suspension is all installed but I have not installed the upper shock mount yet. I put the bar in place, but have not decided where it should go. Should I just move it forward and get longer shocks, or is there a problem when the bar is moved forward? I will surely install a rear sway bar and bump stops. Also, I don't really want the 2" body lift. Last time I was under I thought that a 1" body lift would still allow enough room for the upper shock mount, but I haven't had a chance to measure the distance between the upper mount and the body with the 2'' blocks. Any help with this would be greatly appreciated. I do think it's a good system but I just want to avoid the shock bottoming out issue before I go any further. Thanks. John ps. looking for a link to the best rear sway bar setup.

 

[chuzie]

According to Duff's I am the first and only person with these issues so, in theory, you should be fine to install the upper shock mount per their instructions. Maybe tack it in pretty well and then flex it out and see what happens.

If all works out as planned, you should not need bump stops as the coils are supposed to completely compress before the shocks do.


I am pretty sure a 2" is mandatory to get the front hoops installed. I have 2" and had to beat the crap out of my wheel well to get them to fit. Not sure about the clearance from the body and the rear upper mount though.

Here is the link the to sway bar info. I have all the parts, just waiting to resolve this shock issue before I install the sway bar.

http://classicbroncos.com/forums/showpost.php?p=1722477&postcount=17

 

[chuzie]

UPDATE:

Today, we tested the 4-link using the same RTI ramp and formula. The front scored 1117 (105/94x1000) and the rear 1160 (109/94x1000). Now we did move the rear axle back 2" which was accounted for in the calculation. Unfortunately, the rear outboard shocks have been an issue since day one. Next week I plan to eliminate the lower tabs on the truss and fab new ones on the lower part of the axle tube. This should give me the needed travel / compression to prevent crunching more shocks.

Once I create the new mounts and verify it fixes the issue, I will have to get new shocks from Duffs since mine were destroyed from bottoming out.

More to come...

 

[01Dudley]

Good talking to you this morning and we will get the shocks out to you today. Can't wait to see the completed project.

 

[chuzie]

Got the replacement shocks installed. Thanks for sending them out so fast.

Unfortunately, I am still not happy with the amount of body roll from sudden turning movements. Ordered a set of monotube shocks to test and see if the extreme roll is reduced as compared to the hydraulic shocks.

Actually, I have considered multiple possibilities to fix this roll issue.

The first was a anti-sway bar. Considering how soft this system is, I am surprised an anti-sway device was not included in the first place.

Next, I considered multiple iterations of shock options between hydraulic, nitrogen, and monotube among the four different positions and even considered going inboard only.

For now, I am going to try the monotube on the outboards to try and handle some of the roll since they are 250 psi and leave the inboards hydraulic to help dampen some of the vertical movement over the axle.

If that doesn't work, I plan to replace the inboard hydraulics with nitrogens. Of course, if all that turn out to be overkill, I may end up ditching the monotubes and running nitrogens all the way across.

FWIW- My RTI score increased from to 1,160 to 1,436 with the pesky outboard shocks removed thus allowing my rear wheel to fully compress into the wheel well.

More to come....

 

[KyleQ]

Nice - get some shots form further away, I'm wondering how that setup compares to my 11 pack rear setup. I've never been able to lift a tire so far - and I've twisted my Bronco up really good.

 

[chuzie]

Nice - get some shots form further away, I'm wondering how that setup compares to my 11 pack rear setup. I've never been able to lift a tire so far - and I've twisted my Bronco up really good.

Probably because between your axles and tires you have a ga-jillion pounds of weight pulling those springs down! ;D

 

[chuzie]

UPDATE:

I fabbed a set of lower shock mounts using .025 wall 2x2 and welded them below the axle tube to eliminate the lower tabs on the truss. They are super stout so I am not worried about them hitting rocks. Installed Skyjacker M95 monotube shocks on the outboards and left the Duff's hydraulics on the inboard positions.

THIS IS A COMPELTELY DIFFERENT BRONCO!!!!

Corners like a champ, much less lean, super stable, better traction, super extension and compression and overall a much better experience.

I really think 4 hydraulic shocks for this system is just too little for the demands we place on it. What I have now is a good combination but wonder if some nitros in lieu of the hydraulics on the inboards would be too much.

Anyway, I am also thinking about getting another set of monotube shocks for the front and am willing to bet they will eliminate any need for a sway bar.

The Duff's system is good buts needs some tweaks. No one has yet to figure out why we had to jam the upper coil mounts so high above the frame to get the body level. That is what caused this mess in the first place. Oh well, I guess I just got the luck of the draw on that one.

If I find my new RTI score I will be sure to post it. Just not sure where I misplaced it!

 

[Madgyver]

bumping up an old thread because David posted a pic of me.. find it..

 

[Yeller]

bumping up an old thread because David posted a pic of me.. find it..

You made me look....... sure enough, standing around with a few other famous peeps

 

[Madgyver]

you made me look....... Sure enough, standing around with a few other famous peeps

........