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And now for something completely different: Antiwrap lift blocks...

WrenchMonkey

WrenchMonkey

NAXJA Member #771
NAXJA Member
Location
East of Cincinnati
A little background:

My rear leaves have been sagging for years. I've been running a set of HiJacker air shocks to get back about 2" of lost lift, mostly because they were cheap and easy.

They actually worked really well: as the air moved from one shock to the other, they would actually make the rig flex more than it normally would. And I've been amazed at how well they've held up, 18 months and at least a dozen wheeling trips.

Til Saturday. A little too much fun at Big Rock with Nick and Tom et al...

Suddenly they just wouldn't hold air. It was slow enough that I couldn't track down the leak, but they'd bleed off 80psi to nothing in a half hour.

Without em, my springs are almost completely flat, even a little S shaped. And losing those 2" is enough to wreck havoc on my driveshaft angles. That's how I blew a ujoint on the maiden voyage with the new engine.

Eventually, I'm gonna need leaf packs, obviously. In the meantime, though, there's something I've wondered about for years, and this is a golden opportunity to try it.

I'm doing blocks.
 
Yeah, I know, blocks suck. The peril, as everyone knows, is axlewrap.

But I figured, if I made the block out of 2x2 box tube, I could make it as long as I want.
And if I made it, say, 24" long, it'd run out under the front spring hanger, like an old Lakewood traction bar.

Maybe put a rubber bumper on the top, and it should eliminate the axle wrap. At first glance, it looked like I'd lose that 2" of ground clearance, but if I tapered the box tube, it really wouldn't hang any lower than a properly arched spring would.

I may lose a little flex. Droop shouldn't be affected at all, but it could increase the compression spring rate. I could hit the bumpstops pretty easily before, so I don't think a little stiffer would be too bad.
 
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There's probably a dozen reasons nobody has done this, and a dozen more why it won't work like I want.

But I really had nothing to lose. For one, I just couldn't drive the XJ like it was. With the angles that far off, the driveline vibes were just awful. I knew I'd kill another ujoint before long. Two, I really don't have the cash for a decent pair of leaf packs right now. And with three different club meetings in the next seven days, "right now" is the timeframe I have to work with. Three, what's the worst that can happen? I could kill the leaves I've got, that are already way past retirement age anyway.

But most importantly, it was something I've always wondered about trying. This was as good an opportunity as I'm likely to see. I figured what the hell, worth a shot.

"A WrenchMonkey's greatest joy is the flinging of poo, and his ultimate goal is simply to see what sticks!"
 
So here's what I came up with:
01.jpg


2x2 box, .250 wall, about 24" long. 30* cut at the leading edge, 45* at the other.

On the topside, there's 1/2" hole accept the springs' center pin, and a 1/4" hole at the front to mount the rubber snubber.
02.jpg


On the bottom, I drilled and tapped a 5/16" hole, and used a set screw to position the shim, like so:
04.jpg

05.jpg


Loosely assembled, pardon the BigRock mud:
06.jpg


Off-topic: In that last pic you can kinda see how I redrilled the springplate to move the axle back about 1.5", here's a better one:
07.jpg


Anyway, with weight on it:
08.jpg


And clamped down:
10.jpg


I should have taken a nice finished profile pic, but I didn't.
I was running out of time to get to work, so I threw the wheels on and test drove it around the block.
13.jpg

14.jpg

15.jpg
 
Drove it to work all week, a local club meeting Wednesday, and out to dinner tonight, and it did great.
It obviously lifted me back up to a full 6" lift, which realigned the driveshaft angles, and smoothed out my vibes.

But I swear I can feel the antiwrap working, too. When I get on it, the ass end tries to rise a bit as it puts the power down.

The ride is a little firmer, but not at all harsh, or even stiff really. Just like it's better put together.

They do hang down just a little lower than I'd like. The angled nose should help, but adding a small skid to the front would bridge the gap between the bar and the spring.

For a few hours work and a bunch of scrap material, I'm thrilled.

I still don't know if I'll keep it long term, but it'll certainly keep me out of the garage till I make up my mind about something better!

Robert
 
Back "in the day" when I ran hot rods, Lakewodd "Traction Action" ladder bars were all the rage. I would suggest that you rebuilt them a bit longer and here is why.

When under acceleration, the shubber is goint to move up transfering weight to the end of the bar. As your setup exists, all of that force is being applied to the spring pack. What you want (read need...) is the force to transfer to the chassis. Only way is to have the snubber contact to bottom of the spring at the mount. This gives a mostly direct connection to the chassis. As I remember it, the instructions from Lakewood were pretty specific about this as it will kill the springs otherwise.

Just my .02 based on decades of trying to get power to the ground. As a wise man once said, Never too much power, just not enough traction...
 
o-gauge-steamer said:
What you want (read need...) is the force to transfer to the chassis....to have the snubber contact to bottom of the spring at the mount.
Click to expand...

You're right, and I may yet have to, but here's why I didn't:

While my springs are almost completely flat, they do still have a bit of arch near the front mount. I positioned the snubber where it would ride right up against the spring, only about 1/4" gap.

Running the bars another six inches forward would get under that arch, and open a relatively huge gap, about 2-2.5".

I could fill it with a spacer, but it would still hang down a full 4", and since the bar was longer, it'd be 8-9" in front of the leading edge of the tire. I think it would look (and work!) like a big yellow anchor.


As a compromise, I guess I could build an angled bar. But it would have been a lot more work, and I was really pressed for time. And I think it might start looking sorta Dr Seuss.


Besides, the worst I'll do is ruin a set of ruined springs...

Thanks!

Robert
 
Good job man. I love when someone does something different and does it on the cheap too.
 
'Not a huge fan of blocks, or slapper bars for that matter, but hey,...

If you're going to do blocks, you need to do something about axle wrap. That's a better solution then most people come up with.
Suggestions:
Weld a piece of 1/4"plate on each side of the bar between the spring and perch, to bring the block out to full spring width.
Add a piece of strap on each side of the bar, 6-10" forward of the spring perch to keep the bar aligned with the spring pack.


Besides, the worst I'll do is ruin a set of ruined springs...
Click to expand...
actually, the worst is you roll the axle out and ruin the springs, shocks, possibly tear up the underside of the truck and break the transfer case from the spinning drive shaft.
Watch those bars like a hawk. Look for deformation/signs of crushing around the spring perch. Check the torque on the U-bolts regularly.
 
Why not just do blocks and a traction bar? What you have done looks great and you got lift out of it but it will do little to reduce axle wrap when braking hard, it will work fine while climbing but the bar has to be reducing the amount of compression those springs will give you.

Just a thought, traction bars are easy to make. I'm building mine out of 3 old stock trac bars, a hiem joint and some scrap 1-1/2" DOM.
 
tbburg said:
'Not a huge fan of blocks, or slapper bars for that matter, but hey,...

Weld a piece of 1/4"plate on each side of the bar between the spring and perch, to bring the block out to full spring width.
Add a piece of strap on each side of the bar, 6-10" forward of the spring perch to keep the bar aligned with the spring pack...
Click to expand...

I'm not normally a fan, either, but combining the two was just odd enough to try.

I planned to plate the sides, but I had one night (at work) to get it done up, and just ran out of time. If I do a v2.0, I'll use those side plated to incorporate a bumpstop mount.

I didn't think of the guide plates, that's not a bad idea.
If the bars end up wandering on me, I'll add them.


tbburg said:
actually, the worst is you roll the axle out...
Click to expand...

I've heard of that happening, but the only way I can see it is if I broke a ubolt. I have been checking them often, they are holding a lot of layers together.

I'll watch the bars, but .250 wall 2x2 is stout. I'm not too worried...

Thanks for the notes!

Robert
 
xjtrailrider said:
it will do little to reduce axle wrap when braking hard...
Click to expand...

I didn't show it well, but the bar does extend 6" to the rear to help spread the opposite load. I'm not too worried about braking, since there's no load on the driveline.

I'm a little concerned about a hard reverse, especially offroad. But that length will held spread the load some. We'll see.

xjtrailrider said:
Just a thought, traction bars are easy to make. I'm building mine out of 3 old stock trac bars, a hiem joint and some scrap 1-1/2" DOM.
Click to expand...

Well, like I said in that old thread:

WrenchMonkey said:
Well, I guess "easy" is a relative term.

Remove the rear axle,
Fabricate and weld on a mounting bracket,
Reinstall axle,
Design, fabricate and mount a new crossmember,
(Working around the driveshaft and exhaust)
Design, fabricate and install a three-ended, swiveling traction bar.

Yeah, sure. Easy! :D
Click to expand...

:cheers:

Robert
 
I'm building mine on the drivers side. I built the bracket on the axle when I trussed it and set-up my 4.88's

Here is the plan, in theory it will work and still allow the axle to droop/compress while eliminating axle wrap.

tractionbar.png


Here is the bracket on my axle, its done and ready to go. You can see it on the drivers side of the diff. It is supported by the RuffStuff truss which is beefy as hell.

P1020223.jpg
 
Love it. Cheep and simple, just like me.
The down side. I don't see how your spring could reverse curl. If this is true it would limit up travel. But that would depend a lot on your setup. Or that may just not be a problem for you. Keep thinking outside the box. That's how things get better!
 
WrenchMonkey said:
Yeah, that looks easy. :wierd:

Robert
Click to expand...

Its really not that much fab work for the benefit. I figure i will have 5 hours in the traction bar and $0 amount of money in it since it is made from scrap laying around. I scored a free Currie Johnny Joint end today from a local wheeler to use for the frame end. That will be stronger and flex better than the heim as long as I double shear that end as well.

Sorry for the hijack, your idea works so go for it!

Back on topic
 
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xjtrailrider said:
Its really not that much fab work for the benefit...
Click to expand...

...except you already had the axle truss and bar mount, and you still need to figure a crossmember for the frame side mount. And I'm really not sure about the track bars. Most of us have bent stock bars with just the side-load forces on the front axle, I don't know how they'll hold up to engine torque.

So while I understand that a proper traction bar will work better than my, um, contraption, I'm confident that I've got the benefit-per-effort ratio in the bag!

Robert
 
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