The Blue Bomber gets linked (1 Viewer)

[Toyoland66]

Sorry I think the way I wrote my response was confusing.

I meant keep your horizontal separation the same as you had it before, I think that’s the Y measurement? Put it back where it was previously and with the shorter link the convergence point (the dashed red lines going out from the lower links when viewed from the top) moves back closer to your front axle which will make the oversteer number lower. I would shoot for slightly negative (btw 0 & -5) on that number.

 

[The Eradicator]

If you have the room, triangulating the lowers will help your roll axis significantly. With a wide axle, you might be able to push the axle lower mounts out far enough to allow you to just put the frame side mounts on the frame rails. Also, I'd shorten the uppers; rule of thumb is ~75% the length of lowers.

 

[workingdog]

Okay, I eff up the last change. It throws me that the lower links are on top and the upper links are on the bottom. So I fixed that, but I I don't think I changed the Y numbers.

I had set the lowers where the springs were, this version maximizes them outboard of the frame.

Yes, at stock wheelbase right now. If I move the rear back, I'll have to cut into the rear of the wheel well.

All this moved the instant center forward a lot. Roll axis is still 5 degrees. Squat is good.

 

[workingdog]

here it is fully triangulated, really helps. But, it would require some kind of cross member.

 

[GLTHFJ60]

Having to build a crossmember to hold the links isn't that big of a deal, is it? It could also hold the back half of a skidplate.

 

[workingdog]

It's a big deal for me, it would be beyond anything I'd fabricated before, in that it would actually HAVE to be structurally sound. With the numbers as they are right now, it's a few inches forward of existing cross member for the back of the skid plate. The old numbers were chosen barbecue they would have hit that perfectly and I just could have beefed up. But, I'm up for it, I'll figure something out. At least at the axle end, I can buy a trust for the 14 bolt with upper link mounts ready to go.

Filthy Motorsports is pretty positive about fitting the coilovers in. So, I guess I'm going to take some PVC and mock something up and shove it in there and cycle the axle and see what happens.

 

[GLTHFJ60]

IMO, putting a crossmember in is easy compared to fabricating, and more accurately placing, the link+coilover mounts. That said, I hear you about adding potentially unnecessary work.

FWIW, I'm not sure your current drivability issues will be solved by linking *just* the rear, but I know you're doing both the front and rear.

 

[workingdog]

@GLTHFJ60 - The place I was going to start was putting chevy springs in the rear to replace the failing OME springs that are there. They had leaves removed to get the ass down, and it was a mistake. And now they are failing (the dreaded 'W' at the axle) with 1" of lean to the drivers side. The last trip to the Rubicon fully loaded did them in.

So, looking at all that work, I just figured it was a little more work, and a lot more results, to link the rear, go coilover and then the rear isn't the issue (or, it's an adjustable issue). Once it's dialed in, I'll see if anything improved, and then probably link or tailing arm the front. And I'm hoping I can squeeze coilovers right were the shocks are now on the Dana 60 up front.

Then, at least I'll have done it all myself and if it drives like s***, I won't have anyone else to blame.

I had it out yesterday, and I'm having to do a lot of work just to drive in a straight line. My 40 has the same high steer and same 37 and takes 1/100th of the effort. The toe is set correctly. The caster is at 2. When I link it, I'm going to take the caster to 4 and I hope some or all of that goes away. The body roll certainly can't get any worse.

 

[cruisermatt]

I was going to say a few crossmembers would be wise, along with an upper brace for the front coil-overs in the engine bay. The 60 frames are pretty flexy, and chassis rigidity is a good thing.

 

[workingdog]

Okay, continuing to work on this confirming and validating measurements. Here are two options.

One has 49" long lowers (the long lowers option) that uses the existing cross member that's the back the skid plate and basically at the rear cardan joint.

The other is shorter lower links (as was recommended) that will require a new cross member 9" behind the back of the skid plate that will have a slight bump out to accommodate the rear drive shaft.

I've kind of figured out what I have to do to drive the anti-squat up and keep the roll center down. Both have good numbers.

Long lowers

Short lowers

 

[Toyoland66]

I haven’t messed with the calculator in a while, is there a way to see what the geometry does in travel using those bump & droop buttons?

Numbers on both look good static but one may have better driveshaft plunge or pinion angle change during travel.

 

[TrekkerOverlanding]

You’ve got me inspired.

 

[workingdog]

Yes, you can run it through drop and compression and it will show you change in pinion angle.

So, I'm trying to figure out how to move from 'it seems like a good idea' to 'yes, this will work, I can commit and order parts and start tearing the rig apart. How do I confirm that what I have on paper will actually work in my truck. I've been under there trying to mock it up with string and stuff, but the exhaust and traction bar are in the way to much to actually do a workable mock up and I'm loathe to tear the rear of the truck apart without a solid plan in place I can move ahead with.

 

[muddogbob]

What’s the reason for linking the rear vs using 63” leafs? I’ve been SOA on stock springs and will be putting in 63s and a 14 bolt this year.

I’m considering a 3-link up front in the future.

 

[workingdog]

If I'm going to do all the work to put in 63" in leaf springs, it seems like it's not that much more work to link it - and for me, I'll get a lot more from it - I can get it down an inch or two, and I'm hoping I can get much better behavior out of the rear end.

 

[muddogbob]

Here’s 4WUG link kit on a 4runner

 

[tmxmotorsports]

Here’s 4WUG link kit on a 4runner

View attachment 2022263

That top link bracket is big af

 

[workingdog]

Thanks for the picture. It looks like the same configuration I came to. Parallel top links, rising lower links.

Can't find 4WUG on google. Not sure if it's a company or an acronym. the tower on the diff is HUGE. I don't that kind of room. The rig must be really tall. Are those old coil brackets?

 

[muddogbob]

4wheel underground, they have a website.

They also make a spiffy 3-link front for 80 series.

I sent them a note for fj60s, but never for a response. I’m guessing the 80 series kit would work with a little messaging.

 

[workingdog]

The one they make is a 3 three link with panhard for the front. When I get to the front I will definitely look at it. I have no idea how different the front of an 80 is from a 60.