Gawynz Buggy Thread

Gawynz

Active Member
Location
Ogden, UT
I know that little Jeep...because it used to be mine! I sold it to Rick. Looks like he decided to sell it....It was always one of those one day projects....maybe one day I'll get another.

That's awesome. Once I got the thing home I got to looking it over and I really just wanted to keep it but I don't think my brother would have taken that too well ha. The guys I bought it from had quite the collection of rigs, it was fun just looking them over and talking with them for a bit. I think they showed me like three other Willys in some form or another and they'd just decided they didn't need this one.
 

Greg

Make RME Rockcrawling Again!
Admin
I know that little Jeep...because it used to be mine! I sold it to Rick. Looks like he decided to sell it....It was always one of those one day projects....maybe one day I'll get another.

I thought it was your old one soon as I saw the number on the side, too funny!

The Willys looks awesome @Gwaynz, too funny about snaking the sale from your brother and then surprising him with it!
 

Gawynz

Active Member
Location
Ogden, UT
I got tired of having to go down into the basement every time I had to take a piss so I took a break from the buggy and finished the remodel on my upstairs bathroom. I spent a lot of time this weekend working on the buggy; a lot of measuring, checking, making tabs, mocking stuff up, cycling, double checking, etc. but I think I'm getting closer... I think.

I've cut nearly every tab/mount point off the back of the buggy; all the axle and frame link mounts, all the shock mounts, seat harness mounts, limit strap mounts... so my shop is a wreck with grinding dust and I'm getting a lot of practice making cardboard templates. I started with the lower links and was able to get the 45deg I was targeting out of them.

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All of my lower links used Low Range Offroad 1.25" rebuild-able heims, in the process of disassembling one of them I had an impatient and stupid moment and ruined the threads on one... They no longer make this joint so I ordered the same style Currie Johnny Joint to replace it. I was surprised to see how much different the two joints were in size. So without further ado... an obligatory and cliche picture of a heim joint next to a 12oz beer can... based on my research this seems to be the communities standard unit of measure when comparing heims.

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Next I did the upper links. On the axle side I had to widen the C-channel a tad to get two heims to fit. At the chassis, the original link points were <45deg, a tad too low, and not quite lined up right so I repositioned/remade those. I used PVC to mock up the upper links along with two ratchet straps to pull the opposing heims towards one another so that the PVC didn't fall out. Using PVC was very helpful, throughout this process setting pinion angles and adjusting for clearance I trimmed or remade the PVC links numerous times. Once I had all four links tacked in place I cycled the suspension targeting 9" up and 9" down (18" ADS coilovers).

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Clearance was good, my only issue was drive shaft angles. I mocked up the carrier bearing mounting location so that my midship was running at a downward angle of 18deg from the transfer case. I plan on using a standard 1350 u-joint at the transfer case but at the carrier bearing joint and pinion I'll have to run Tom Woods 1350 Superflex Joints. I tried to avoid this, but I can't find a way around it. I even considered chopping up the back frame to run a single piece draft shaft but I don't have the clearance when articulating. The maximum angle that my draftshaft will run at the carrier bearing or pinion is ~32deg. The Superflex Joint is supposed to be good up to 40deg. At ride height, the pinion, driveline, and midship are all within ~3deg so I'm hoping vibration isn't too bad... but if I'm going to have to make a compromise, vibration isn't that big of a deal in a buggy.

Finally I mounted the coilovers. At full compression I was targeting the coilover being perpendicular to the lower link. Once I had the links tacked in place I mounted the coilovers and articulated to check for binding and clearance of the coilovers and tires. Everything clears and looks good.

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The good... it all seems to fit as I was hoping. The bad... more expensive drive shafts. The ugly... rear steer is significant. I tried to minimize the rear steer but can't figure a way to do it. I think that it's inherent to this suspension linkage design as the upper links LCP is so high resulting in the steep roll axis. I hope this isn't too annoying, but I guess it is what it is. The rig has always had rear steer, I figure I'll just learn to drive it. Orrrrr, actually add rear steering to the buggy... maybe someday.

Full stuff

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Full droop

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Articulation

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So that's currently how it sits. I'm trying to figure out the smartest way to go about finishing it up.
My plan is:
  1. Build the mount for the carrier bearing and get it set in place.
  2. Order the driveshaft and install it.
  3. Run the suspension through it's cycle and verify clearance and angles.
  4. Build the upper links.
  5. Put old springs on the coilovers to get sprung weight, calculate, order new springs.
  6. Pull the axle and fully weld everything.
  7. Paint and assemble.
So what did I miss? Thoughts, advice, etc. let me know.
 

RockChucker

Well-Known Member
Location
Highland
How long are your links? That is probably the biggest contributor to your axle steer problem because the link's angle change is so huge with 18" of travel. Doesn't look like an easy fix though.
 

Herzog

somewhat damaged
Admin
Location
Wyoming
I think it does have a lot to do with the upper link tower being so high and the mounts being so close, the pivot point is centered there. Here's my brain in a graphic:

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It would help if you could get the upper mounts spread further apart but kept the same degree of triangulation.
 

crosbike

Active Member
Location
Utah
Whats stopping you from cutting off that huge tower on the rear axle and lowering the axle and frame side upper control arm mounts? Seems like it would help with packaging and you'd gain some storage on the buggy itself.
 

Gawynz

Active Member
Location
Ogden, UT
How long are your links? That is probably the biggest contributor to your axle steer problem because the link's angle change is so huge with 18" of travel. Doesn't look like an easy fix though.

I think it does have a lot to do with the upper link tower being so high and the mounts being so close, the pivot point is centered there. Here's my brain in a graphic:

Thanks @RockChucker and @Herzog, I agree with both of these comments.

Based on everything I've read and seen my links are very short, lowers are 26.5" and uppers are 20.5". From what I understand, link length contributes to rear steer more so when the links have a high amount of angle at ride height and/or articulation up/down isn't even. My uppers are level, my lowers angle upward toward the chassis at about 4deg so pretty level as well, and I have even travel at 9in up 9in down. Here is how I envision link length affecting rear steer for a typical four link setup with equal up/down travel and level links at ride height... Imagine:
  • The the rear axle is at full stuff - no rear steer
  • The driver side begins to droop, while the passenger side remains at full stuff. As the driver side droops the driver side links become more level, pushing the drivers side of the axle backwards - rear axle steers to the drivers side
  • The driver side reaches ride height, while the passenger side remains at full stuff - max axle steer to the drivers side
  • The driver side axle droops past ride height causing the drivers side links to angle upward and pull the drivers side of the axle back towards the chassis - drivers direction rear steer being reduced
  • At full articulation, both the drivers and passenger side links are angle up and down at even angles, locating the axle front to back in the same position - no rear axle steer
So while my short links definitely affect the rear steer I don't think I'd be seeing it at full articulation due to the fact that my links are essentially level and my compression/droop travel is equal.

Like @Herzog and @crosbike pointed out, I think the big cause of the axle steer is the super high upper link tower on the axle.

Whats stopping you from cutting off that huge tower on the rear axle and lowering the axle and frame side upper control arm mounts? Seems like it would help with packaging and you'd gain some storage on the buggy itself.

I could cut down the link tower and go with a more traditional four link setup, but this high link tower is the reason I'm able to keep the CG under the roll center and get the buggy to handle the way it does; tucking into corners and leaning uphill in off camber situations.

Rather than heaving a 14 bolt around, I threw this model together this weekend and played with it to understand what's actually going on in my setup. It's not perfect, but it's very close to the dimensions of my suspension, and close enough to understand the concepts of what's going on.

I think that the biggest reason I'm seeing rear axle steer at full articulation is because the differential is moved so far to the side (like @Herzog pointed out in his picture), similarly the link mount points are moved equally as far. If you look at the X-Y plane of the lower link geometry you can see how the compressed side link angle becomes more acute while the droop side link angle becomes near 90deg. The compressed side pulls the axle towards the chassis and the droop side pushes the axle away causing it to steer towards the droop side. The amount the axles swings left to right would be reduced if I reduced the axle tower upper link height which would also reduce the amount of rear steer.

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In the end, there isn't a lot I can do about it without making major changes. The differential swinging side to side so drastically is due to the tall upper axle link tower but the link tower is also the cause for the desirable handling characteristics. Lengthening my links would help, but my wheelbase is already long (120"), moving the axle back would cause it to hit the chassis/radiator, and the chassis side mount points are already right behind the seats. I think i'm only getting about 4deg of axle steer which isn't too bad. Like I said earlier, the rig has always had some rear axle steer that I can feel, I'm just going to get used to it and wheel it, hopefully without too much frustration.

Sooo... after thoroughly beating that horse to death... I'm not going to do anything different. :rolleyes:
 

Gawynz

Active Member
Location
Ogden, UT
After I posted I just had this thought... if I didn't triangulate my lowers I could eliminate the rear steer. The angles between the two lower links in the X-Y plane would match so the axle would move forward and back equally on both the driver and passenger side. As I explained earlier though, I think that the lowers do a lot of the work in laterally locating the axle due to how high the uppers are mounted on the link tower. I think it'll be best to leave it double triangulated and just deal with the axle steer.
 

xjtony

Well-Known Member
Location
Grantsville, Ut
Is there a happy median where you could run less of a triangulation, lessening the rear steer issue, but still locate the axle laterally? I wonder what effect having the uppers so high would really cause?
 

Gawynz

Active Member
Location
Ogden, UT
It's been a while since my last update. Throughout June I remodeled two bedrooms in my house and built a dog kennel/run, now back to making progress on the buggy.

I needed to settle on a driveshaft before I went much further... I didn't like the idea of running a superflex joint on a two piece driveshaft for alignment and vibration reasons, and a double cardan high angle driveshaft is very expensive. I figured I'd give it a shot and try and make my current driveshaft work before going down one of those two routes or compromising on the droop I was targeting. I could see where the driveshaft was binding at an inch or two short of full droop; so I pulled the shaft apart and began "polishing".

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Shot each ground area with a coat of paint, installed the shaft in the buggy, drooped it out to lightly binding then turned the shaft by hand to identify the rub spots in the paint... pull, disassemble, polish, repeat. I did this about 4 times before I was able to get appropriate clearances to avoid binding. I tried to minimize the material removed so hopefully not to compromise strength too much... but I guess we'll see. Removing this small amount of material, I was able to get ~5deg more out of my double cardan, and get the full 9" droop out of the rear end. Once I was happy with everything I cleaned up the shaft components, painted everything, and installed new u-joints.

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Had to notch the frame to clear the single piece drive shaft, didn't turn out as drastic as I had originally estimated.

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Finally, it felt like I was done cutting stuff off and moving in the reassembly direction... not quite. I got the axle back underneath with everything installed and was running it through it's full range of motion checking angles, clearances, etc. and I noticed that when fully articulated passenger side high the rotor was much closer to the chassis than the drivers side rotor was when articulated driver side high. Started checking and rechecking everything to discover that the axle side upper link tower wasn't centered on the axle relative to the hub faces; it was centered on the pinion but the pinion isn't centered on the axle. Sooo... pulled the axle again and cut the tower off as flush as possible trying to minimize height loss as I didn't really want to rebuild it. Shifted the tower to center relative to the hub faces, tacked in place, put it back under the buggy and fiiiiinally got all the clearances/angles I was looking for.

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Once I convinced myself I was happy with everything I pulled the axle hopefully for the last time and started burning everything in.

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One of the things I'm not too happy with is the spline engagement at full droop (@CSR called it). At full droop I only have ~1X the spline diameter engaged, seems like a bad idea as most sources I've found recommend 1.5X - 2X. I figured that the only time I'm going to be getting this little engagement is when I'm bellied out or in the air, so either way, not much torque on the shaft so hopefully it'll hold up. If/when it does break, I called Tom Woods Driveshafts and they said thy could likely salvage my polished double cardan and replace the back end with their ultimate travel driveshaft.

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So after a short hiatus, that's where I currently stand. I need to finish welding all the tabs and add a few tubes back, then get it under it's own weight on the old springs, do some measuring/math and order some springs.
 

zukijames

Well-Known Member
Location
not moab anymore
My super tall upper link tower and Lower links mounted above the axle give me some rear steer too but when I was originally mocking up my suspension I had tons of triangulation on my lowers and it was pulling the axle side to side really bad went less and it made a big difference
 

Gawynz

Active Member
Location
Ogden, UT
My super tall upper link tower and Lower links mounted above the axle give me some rear steer too but when I was originally mocking up my suspension I had tons of triangulation on my lowers and it was pulling the axle side to side really bad went less and it made a big difference

Yeah, i think you're right; I think with less lower triangulation I'd get less rear steer. It's a compromise I guess, better/stronger side to side axle location at the cost of rear steer. I'll give it a shot and see how it works, if it's awful it shouldn't be too big of a deal to relocate the lowers.
 

zukijames

Well-Known Member
Location
not moab anymore
Yeah, i think you're right; I think with less lower triangulation I'd get less rear steer. It's a compromise I guess, better/stronger side to side axle location at the cost of rear steer. I'll give it a shot and see how it works, if it's awful it shouldn't be too big of a deal to relocate the lowers.


I like triangulated lowers because they push on the center of the chassis. Straight lowers push on the outside and if one tore gets traction and the other does not on a steep climb it will swing the nose of the rig.

I suck at explaining things.

Working on my wife’s rebuild now and running. High links on it also .
11AAA3C2-3761-455D-AA85-2C750405DFE3.jpeg
 

Gawynz

Active Member
Location
Ogden, UT
Update time...

Made the rear upper links

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Since I shifted the axle link tower over I had to plug/weld the original mounting holes for the diff cover in both the tower and cover and redrill.

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Cleaned/painted everything, added gear oil, then finally got the axle back on the tires, installed, and squared up.

install.JPG

Then it was onto the exhaust. Originally, the upper links would hit the exhaust at ~3.5" of down travel, now I have 9". After I marked out where I had interference I ended up cutting the exhaust into three pieces, adding a little here and there and got it to work. I'm pretty happy with it; plenty of clearance, straight and tight, and didn't require rebuilding the entire thing.

exhaust.JPG

Installed the old springs and got it set to the new ride height (19" belly), brakes, etc. and then finally drove the thing! At least pulled it out of the shop for some sunlight and got it flipped around ha. Cleaned it off a bit then pulled it right back in the shop. Flipping it around wasn't a big deal, but driving it sure was motivating to get it finished and actually hit a trail.

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Then yesterday I got busy on the front end. With the driveshaft not installed and the original linkage I cycled the suspension to see where I was at. The thing has tons of up travel, down travel also looks pretty good (plan to run a two piece driveshaft to avoid frame), the issue is during articulation passenger side high my pinion hits the chassis. I plan to cut out this tube of the chassis and move it inwards.

cycle.JPG

As I mentioned earlier, both front and rear I want to get away from the wishbone upper link setup because it's a single point that can fail and wreck a bunch of things. I'm glad I'm going this route, when I removed the front, upper, single heim I found that the shank was bent.

I liked the forward location of the axle, so I set the pinion to 0deg and started mocking up the new upper links and mount points.

mock up.JPG

Here's a comparison before and after.

before and after.JPG

I welded the bungs in the upper link tubes last night and that's where I left off.

I'm hoping that I can mount my winch between the upper and lower links to the front of the chassis keeping it below the hood line. I'm going to try and use the lowers, although I wish my coilovers were mounted further forward. I plan to work the chassis next to avoid the pinion at articulation. Progress! ?
 
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