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[another_mike]

Hi guys, I I rarely if ever post. But read many of the threads on this forum in particular that one’s relating to 4 x 4 vans. I too have have a coil spring 4 x 4 van that was built using a mix of U-Joint parts and other off-the-shelf parts. As soon as the van was drivable there was the infamous DW. But was quickly and easily remedied by simply adjusting/adding greater negative caster. I my case, granted this was quick and easy as I have a 4/5 link system. If searching through the Internet for answers for DW the vast majority of information is basically the same as the comments here in this post, throwing parts at it, adjusting toe etc though if you dig deeply you will find some info that caster is the culprit in modified coil sprung vehicles. I don’t believe that worn parts are the inherent cause of DW on modified 4x4 coil sprung vans/vehicles, its a caster adjustment. Finally my observation on dual steering stabilizers, why demonize a product that is proven to help steering issues related to lift and big tires. To the OP I hope that this helps solve your DW! To MG you were my inspiration to go coil sprung, thank you! My coil sprung van rides almost as smooth as my old independent Toyota PU.



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Greater negative caster? I always thought it was more positive caster that was needed. How much negative caster do you have?

edit: i guess you didnt say you actually had neg caster, but whats your caster now? whats your lift/tire size?

 

[Chuxideas]

Hi guys, I I rarely if ever post. But read many of the threads on this forum in particular that one’s relating to 4 x 4 vans. I too have have a coil spring 4 x 4 van that was built using a mix of U-Joint parts and other off-the-shelf parts. As soon as the van was drivable there was the infamous DW. But was quickly and easily remedied by simply adjusting/adding greater negative caster. I my case, granted this was quick and easy as I have a 4/5 link system. If searching through the Internet for answers for DW the vast majority of information is basically the same as the comments here in this post, throwing parts at it, adjusting toe etc though if you dig deeply you will find some info that caster is the culprit in modified coil sprung vehicles. I don’t believe that worn parts are the inherent cause of DW on modified 4x4 coil sprung vans/vehicles, its a caster adjustment. Finally my observation on dual steering stabilizers, why demonize a product that is proven to help steering issues related to lift and big tires. To the OP I hope that this helps solve your DW! To MG you were my inspiration to go coil sprung, thank you! My coil sprung van rides almost as smooth as my old independent Toyota PU.



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Greater negative caster? I always thought it was more positive caster that was needed. How much negative caster do you have?

edit: i guess you didnt say you actually had neg caster, but whats your caster now? whats your lift/tire size?

6ish inch lift 35” tires. Caster was adjusted by hand/feel whatever, simply by equally and incrementally make adjustments at the rod ends. Until DW disappeared. Also, I did forget to mention that a badly balanced tire did make DW worse in my case.


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[java]

Caster is what helps self center, I can see additional caster helping....

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[Jeffer949]

Greater negative caster? I always thought it was more positive caster that was needed. How much negative caster do you have?

edit: i guess you didnt say you actually had neg caster, but whats your caster now? whats your lift/tire size?

Curious of the thought process on the less or negative caster. Could it be that the castor is what is trying to return the wheel to straight and with the tire weighing so much the enertia pushes it past straight and then it just goes back and forth?? Thus less castor would mean the tire would not try to self straighten as much??

 

[Hyperdrive]

It is so interesting to see people have issues with conversions and then a ton of people have great driving rigs with zero issue.

I have over 20,000 miles on my MG/Expo Coil Conversion. 8,000 this winter on a trip through Mexico on some awful roads and wonderful dirt where to be honest we beat on our Van pretty good. No DW or any issue on my van. Michael has been wonderful to work with and I can confidently say is liberal with his time.

Good luck solving your issues.

 

[Chuxideas]

Hi guys, I I rarely if ever post. But read many of the threads on this forum in particular that one’s relating to 4 x 4 vans. I too have have a coil spring 4 x 4 van that was built using a mix of U-Joint parts and other off-the-shelf parts. As soon as the van was drivable there was the infamous DW. But was quickly and easily remedied by simply adjusting/adding greater negative caster. I my case, granted this was quick and easy as I have a 4/5 link system. If searching through the Internet for answers for DW the vast majority of information is basically the same as the comments here in this post, throwing parts at it, adjusting toe etc though if you dig deeply you will find some info that caster is the culprit in modified coil sprung vehicles. I don’t believe that worn parts are the inherent cause of DW on modified 4x4 coil sprung vans/vehicles, its a caster adjustment. Finally my observation on dual steering stabilizers, why demonize a product that is proven to help steering issues related to lift and big tires. To the OP I hope that this helps solve your DW! To MG you were my inspiration to go coil sprung, thank you! My coil sprung van rides almost as smooth as my old independent Toyota PU.



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Greater negative caster? I always thought it was more positive caster that was needed. How much negative caster do you have?

edit: i guess you didnt say you actually had neg caster, but whats your caster now? whats your lift/tire size?

6ish inch lift 35” tires. Caster was adjusted by hand/feel whatever, simply by equally and incrementally make adjustments at the rod ends. Until DW disappeared. Also, I did forget to mention that a badly balanced tire did make DW worse in my case.


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So I went back to my notes and found that we have 7° of positive caster.


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[ohsix]

Hi guys, I I rarely if ever post. But read many of the threads on this forum in particular that one’s relating to 4 x 4 vans. I too have have a coil spring 4 x 4 van that was built using a mix of U-Joint parts and other off-the-shelf parts. As soon as the van was drivable there was the infamous DW. But was quickly and easily remedied by simply adjusting/adding greater negative caster. I my case, granted this was quick and easy as I have a 4/5 link system. If searching through the Internet for answers for DW the vast majority of information is basically the same as the comments here in this post, throwing parts at it, adjusting toe etc though if you dig deeply you will find some info that caster is the culprit in modified coil sprung vehicles. I don’t believe that worn parts are the inherent cause of DW on modified 4x4 coil sprung vans/vehicles, its a caster adjustment. Finally my observation on dual steering stabilizers, why demonize a product that is proven to help steering issues related to lift and big tires. To the OP I hope that this helps solve your DW! To MG you were my inspiration to go coil sprung, thank you! My coil sprung van rides almost as smooth as my old independent Toyota PU.



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Not to derail this thread, but what kind of 4 link system do you have? I don't think I've seen one on a van.

 

[Jeffer949]

So I went back to my notes and found that we have 7° of positive caster.


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a quick google search says spec is 2-7.5deg. so 7 is really high.

 

[Farfrumwork]

High caster angles are generally equated to stable steering. BMW's use a LOT, and in my experiences with Subarus people add caster to well over the normal Fuji specification (in order to get a BMW-like steering feel).

Another non-expert here, but I saw the video and thought 'suspension geometry'.

It is weird that this van has what looks to be severe DW, when others report little or no DW on very similar setups. The engineer in me asks - what's different? I have a hard time believing that the frame is the culprit, but I'm imagining that geometries will vary greatly between different 'hand built' 4x4 systems.

 

[watson.robin]

Not to derail this thread, but what kind of 4 link system do you have? I don't think I've seen one on a van.

Yes, I'm also curious.
I'd love to see a pic of it too if you've got one.

 

[Myvanisbetter]

I had a coil sprung conversion (not MG) with some pretty surprising death wobble, which turned out to be a combination of 1 failed steering stabilizer of a dual set, plus warped brake rotors and a stuck caliper. Made for a scary ride anytime I touched the brakes.

I'd take a close look at those calipers like Brad mentioned. Mine had stuck and gotten so hot the plastic calipers crumbled upon removal.

Good luck!

 

[Fork-N-Road]

After you have everything cleaned up, I would DEFINITELY have your alignment and drag link checked out. I was texting MG while my van was being aligned and though the as-is kit was going to be close to factory spec, my alignment guy "Dale" (who I have known for 25+ years and is well respected locally) told me I was going to have DW issues without the cams that were installed. Dale doesn't like the cams and wouldn't have suggested them if he thought they were avoidable.

Dale is also the one who found that my trac bar is hitting the Trac Bar mount. I can see a mark on yours in the same spot mine hits, but mine looks a little worse. The bad part is that you don't really feel it hitting the way you do when you hit the end of the steering box. I have just over 1.5 turns to the left before I hit the Trac Bar mount. I'm reluctant to start grinding on the mount, especially with the issues that you are having, but I don't like the idea that the driver needs to be aware to not turn too far left. MG believes that my Pitman arm might need to be reemed a little deeper, but I haven't had a chance to measure the current setup yet. You may have already damaged your drag link if it has hit the mount a few times and I would definitely get that checked.

 

[5spd97]

I agree that brakes could be the culprit that initiates the DW, but any connection that allows the body to shift forward as the brakes slow the front axle could start the oscillation. The brakes want to drag the axle backwards while the mass of the vehicle wants to continue moving forward. And both sides need to be doing the same thing at the same time.

 

[djbonsu]

Gregor, sorry to hear about your issues you're having with your van. Im no expert but the first thing I think about is your alignment specs. How much caster did you have after getting it aligned? Factory f250/350 specs may not be enough for your van application. I believe MG's build initially had about 5-6 deg of positive caster. Good Luck!

 

[Chuxideas]

Not to derail this thread, but what kind of 4 link system do you have? I don't think I've seen one on a van.

Yes, I'm also curious.
I'd love to see a pic of it too if you've got one.

Sorry don’t any that would do it justice right now. The van is in the shop for some performance upgrades turbo, HPOP, injectors etc. Should have it back early next week and will throw a couple of pics up. But hears a basic before and after.

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