So with part 2 we'll pick up with what am I hoping for with these. I've done a lot of upgrades to the suspension since owning the van in Deaver springs, Agile shocks, ball joints, new bushings etc. After all that the areas that I've still felt there could be improvement is steering wander on the highway (too twitchy), hitting the bump stops a lot off highway (too little up travel), and though the suspension is more compliant there is still a lot of harshness transmitted into the cab.
The goal to try the sulastic is mainly a solution to that last part of harshness. I'll elaborate on the before Sulastic behavior here. The sensation from the front seat was two fold. A hard repeated shuddering when on a road that is slightly torn up, a washboard dirt road would be the extreme example. And, a punch you in the kidneys hit when going over a single large bump or drop hitting the bump stop. I've ridden in my friends mostly stock 2000 F350 4x4 with solid front axle/lief spring like mine in the same conditions and there is a similarity to the ride quality but no where as extreme as my van. I realize these are different vehicles but not as different as a Toyota Tacoma and the van.
About a year ago in an attempt to address the wander/twitchy highway driving I installed 2 degree caster shims. (see above) This was a bit of a chore to do in the driveway as you must drop the front axle and carefully unbolt the lief springs to install the shims. Bolt everything back together as accurate as possible because this will effect steering and unlike a multi-link coil-over suspension I can't just turn a wrench to align everything after the fact. This improved the straight line steering immensely except that I must have reassembled crooked as the van then pulled to the right. I worked over everything several times by unbolting and repositioning with a hammer after that and got it better, but never was quite right.
Ok, that's the back story. At this point I have the Sulastic Shackles on, remember they are two inches longer, with the shims still in, and going for a test drive. The picture above shows how the caster angle is getting pretty steep. At full axle droop I'm seeing a tiny bit of splines at the slip yoke. The first drive was very promising with ride quality but the front shaft is starting to vibrate a lot (hubs locked but not in 4x4 at transfer case), the steering clearly has too much caster, the pull to the right is back, and I now have my answer. Must remove shims and try to straighten out the alignment of the springs.
After a day or two of taking the entire front end apart, removing the caster shims and spending a quality amount of time measuring the alignment of the springs. I discovered I was off by 3/16" when I installed the shims a year before. One axle perch was 3/16" further forward. So when resembling without the shims, hoping for the last time, I made sure to be dead equal, left and right.
In the above picture you can see no shim and the 1" (ish) increase in right height, now 3 1/2" up travel, the Sulastic provided. I like this
. The reduction in caster angle made a decent amount of improvement in pinion angle, more than I realized. All looked real good at this point. On the first drive I knew this was the best set up, best it's ever been. However there was still a wicked ujoint vibration in the steering wheel. Took the front shaft the the local re builder (AKA the bearded man yoda of driveshafts) who replaced the lower Ujoint and said,"the balance of that end of the shaft is horrible". After balancing and reinstall not a hint of vibration.
This is where I'm at for now. The Sulastic shackle project improved the three areas I was looking for. The big one was what they advertise in ride quality over "washboard like" conditions. The other benefits of gaining an inch of ride height to the bump stops and hitting a sweet spot of caster angle weren't planned but worked out. Forcing me to correct my spring misalignment was also a good thing. Now my only concern is will the Sulastic shackles hold up over time. My backup plan was to just install the F350 shackles. Now I think a 6.5-7" shackle would be the sweet spot for alignment. I could probably make some up if needed.
So here is the fun part. I have ideas as to how these are working but I was hoping to find more info on the internet of them in real world conditions. In the spirit of Wernher Von Braun who said, "one live test is worth a thousand expert opinions". I rigged up a way to mount my rear dash cam under the van to capture what I was looking to see. Just a head up, this is an industrial documentation video not a #VanLife with pretty people type of video.
So with that I will stop here. Part three will be my theories of how this is all working and a review of what it's like after diving in more conditions.
- Eric
..............
AWOL
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