The Weekend Fun Build

So things are about to get real.

While I'm working on the install, the guys I've been wheeling with have been hatching plans to tackle a couple of Badge of Honor trails up at Big Bear. Gold Mountain and John Bull.

I think I'll be ready for Gold Mountain. Everything I've seen about John Bull says you need 33s or you'll be sitting on the rocks, and lockers are recommended. I'd be on 31s with open diffs. But we're supposed to have an experienced spotter on the run, and that makes all the difference.

This is making me think I need to install armor sooner rather than later. The rock sliders look necessary. And I might even think about adding control arm skids and an engine skid.

I have to think about that while I'm wrenching...
Sounds like familiar territory to me. If you're going to start doing runs that need 33's or a really good spotter, you might start thinking toward the 33's. I hate to say that ($$$), but I did a lot on 31's and got tired of scraping this and hitting that. My oil pan to this day is severely dented. I thought like you, armor sooner than later, rock sliders. I still haven't done the armor, but with 33's it is less necessary for the trails I have done. I would do it with an SYE/DC and TT. That's really all I have left to do with my Jeep, other than comfort changes to interior. But I'm just going to wheel it in my new WA environment for awhile before doing anything. Besides, I'm putting money toward the MTB, as you know.

Great build, great thread, really enjoyed it from post #1!
 
Sounds like familiar territory to me. If you're going to start doing runs that need 33's or a really good spotter, you might start thinking toward the 33's. I hate to say that ($$$), but I did a lot on 31's and got tired of scraping this and hitting that. My oil pan to this day is severely dented. I thought like you, armor sooner than later, rock sliders. I still haven't done the armor, but with 33's it is less necessary for the trails I have done. I would do it with an SYE/DC and TT. That's really all I have left to do with my Jeep, other than comfort changes to interior. But I'm just going to wheel it in my new WA environment for awhile before doing anything. Besides, I'm putting money toward the MTB, as you know.

Budget is the big issue. My first thought for the Jeep was that it would be an accessory for the mountain bikes — a good way to shuttle bikes to trailheads. There are quite a few places my clearance-challenged Subaru can't get to. But now that the Jeep has taken on a life of its own, it has to share disposable income with the bikes.

Unless I have an exceptionally good year at work (which happens sometimes), it's going to be a long while before I could spend the money to get into 33s.

So I have to make the most of 31s for now. And I've seen quite a few comments on this forum from people who had built around 31s and had a lot of fun wheeling, then upgraded to 33s and wished they had stayed with 31s. I'm sure that's not everyone, but there's an argument that wheeling on 31s can be a darn good time.

That's a long way of saying I'm building for 31s and I'm going to make the most of what the Jeep can do with that. But I'm trying to make choices that would make sense if I ever go to 33s.

Great build, great thread, really enjoyed it from post #1!

Thanks, man!
 
After a setback with two crappy drills that weren't big enough for the drill bit I needed to use (I need better tools!), I had a productive day in the garage yesterday. The new front and rear track bars are in.

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They're just hand tight for the moment because they're going to need readjustment after the new springs go in.

The ZJ tie rod upgrade is next. I threaded the ends into the adjustment sleeve this morning, and dang that beast is big! It's beefy for sure, but it's also long. At the shortest I can make it, it already looks like it's just as long as the stock tie rod. I hope it fits! Or maybe the steering geometry changes that happen with the lift will provide a little more space. We'll see what happens tomorrow!
 
This is making me think I need to install armor sooner rather than later. The rock sliders look necessary. And I might even think about adding control arm skids and an engine skid.

I have to think about that while I'm wrenching...

that's Jeep life ... one mod leads to ten others 🤑
 
After a little more careful eyeballing, I figured I didn't need to test fit the ZJ tie rod before installing it. With both ends fully threaded into the adjustment sleeve, it's actually about an inch shorter than the original tie rod. So I went ahead and painted it.

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It's probably the worst rattle can paint job known to man, but I did get a couple of nice coats of self-etching primer under the black enamel, and I don't care how the tie rod looks as long as it doesn't rust.

I also managed to get the new OME front springs installed today. The new springs are actually 2.5" longer than the old springs, so squeezing them in was a challenge. I did manage to muscle them in by disconnecting control arms and flexing the axle, with a little extra leverage from a pry bar to get over the last bit of the axle pad.

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This is just a temporary install to get the Jeep set at the new ride height. I'll do the rear springs next, then adjust the track bars, install the new tie rod, and realign the front end before taking the springs back out to complete the bump stop check. So the Jeep is back down on it's front wheels again.

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But the rear wheels are off and things are already disconnected for the rear spring install tomorrow.

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Tomorrow we find out if I can get the shocks out of the upper mounts without having to cut out the bolts and old nuts. They've been soaking in penetrating oil all week and this is a SoCal Jeep that's never seen a real winter, so I have hope. But worst case, I'm prepared to get in to the top mounts with the Dremel and do some damage.
 
Some good progress in the garage today. I started out the day with everything ready for the rear spring install.

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Thankfully, the rear shocks came out without any fuss. I guess this is why we pay so much to live in California.

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The old rear springs just dropped out (as expected) and the new rear springs weren't any trouble to slide in, even though they're 2.5" longer.

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Here's the Jeep temporarily at it's new ride height. It's sitting on the new springs so I can properly set up the new track bars and the new tie rod. It looks good, but I got a little more lift in in the rear than I was expecting.

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That's about a 5 cm lift in front and a 6 cm lift in back. In total, there's about 5 cm more gap to the rear flares than the front flares. I've been holding on to a 3/4" spring spacer, so I'm going to install that in the front to even out the gap a little. That brings me to about a 2.5" lift, which is excellent because the next mods are going to add some weight to the Jeep and bring me back down a bit.

The paint on the new ZJ tie rod was no longer tacky, so that went in today too with a new front alignment.

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At this point all of the suspension and steering linkages are set up for the new ride height. So now I can go ahead with the bump stop checks. On paper, I'm going to need about 1" of additional bump stop in front for the shocks, and no additional bump stop in back. But I have to make sure the new track bars and tie rod also clear everything.
 
I was puzzled by one thing today during the install. This little hose kept coming off of the rear axle while I was working back there.

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I fished around to where it runs up over the top of the gas tank, and it seemed to have gotten jammed in with the other stuff up there. I was able to wiggle it free, and it seems to have a little more room for extension when the axle droops.

I'm guessing it's the axle breather, but it's kind of odd that it plugs into the brake tee. I'm tempted to get a better clip to attach it, but I'm also thinking that letting it slide off the fitting may be the best way to protect the hose and whatever's at the other end.

Does anyone know what this hose is? Do I need to get a longer one to accommodate a 2.5" lift? Or do I just need to do a better job of making sure it doesn't get tangled up above the gas tank?
 
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I was puzzled by one thing today during the install. This little hose kept coming off of the rear axle while I was working back there.

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I fished around to where it runs up over the top of the gas tank, and it seemed to have gotten jammed in with the other stuff up there. I was able to wiggle it free, and it seems to have a little more room for extension when the axle droops.

I'm guessing it's the axle breather, but it's kind of odd that it plugs into the brake tee. I'm tempted to get a better clip to attach it, but I'm also thinking that letting it slide off the fitting may be the best way to protect the hose and whatever's at the other end.

Does anyone know what this hose is? Do I need to get a longer one to accommodate a 2.5" lift? Or do I just need to do a better job of making sure it doesn't get tangled up above the gas tank?

It's the rear axle breather. The hose runs up the driver side along the fuel filler hose and has a check valve at the top. Front axle has a similar breather with a check valve at the top of the radiator, driver side. They let the axles breathe without water entering do to the one way check valve, so leaving it unhooked is a bad idea. I ended up extending mine 3". Once you have the shocks installed, they will limit the axle droop, so that will help some.
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It's the rear axle breather. The hose runs up the driver side along the fuel filler hose and has a check valve at the top. Front axle has a similar breather with a check valve at the top of the radiator, driver side. They let the axles breathe without water entering do to the one way check valve, so leaving it unhooked is a bad idea. I ended up extending mine 3". Once you have the shocks installed, they will limit the axle droop, so that will help some.
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Great! That's just what I figured, but the FSM and parts list really aren't specific about that hose. I was thinking about an extension just the way you did it. Seems much easier than dropping the gas tank to get at the top end of the hose!
 
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I spent a fair amount of time today cycling the front suspension and learned a few things. The first surprise is that I probably didn't have enough bump stop for my 31" tires before all this started. Here's the gap at the bump stop with a test-fit hockey puck extension at full flex with the wheel rubbing the fender:

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However, that axle position isn't something I can get to while driving because the opposite end of the axle is drooping free without the shock to limit the droop. From this I learned that when you're checking how your tires fit, you need to have your shocks installed to keep the axle in a real-world operating range. But you do want the shock to limit droop on the low end of the axle, which I failed to do in last year's Bump Stop Check Walk-Thru.

Without any bump stop extension, I found that the ZJ tie rod contacts the JKS track bar at full bump. However, with the 1" extensions, that's no longer a problem. (Without extensions on the left, with 1" extensions on the right.)

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With the new RS5000x shocks in place, I need a little more than 1" of bump stop extension to protect the shocks at full bump. The real surprise is that I need more than 2" of bump stop extension to protect the shocks at full flex.

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I didn't realize before that there was such a big difference between full flex and full bump, but now I can see that the offset of the various components matters a lot. So, in the end, I will be running two hockey pucks on the axle pad, plus a couple of washers on top of the bump stop cup, plus the old, smaller poly bushings on top of the shocks. All that together lets the bump stop start taking load right before the shock hits full compression at full flex.

With >2" of bump stop extension, there's plenty of space for the tie rod and track bar at full bump. And there's also plenty of space for the tires in the fenders.

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So, I've ended up with ~2" bump stop extension when I expected 1", but I can see why my 1" estimate on paper was about right for full bump and why it was wrong for full flex. I think I'm happy with the result, and now I need to install the new extensions.
 
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Shout out to @jjvw for always saying how important it is to cycle your suspension. I feel like it was definitely worth the time to do that carefully yesterday. I know a lot more about the setup I'm working with, and I even spotted some mistakes I made the last time I did it.
 
There is a lot to learn from cycling the axles. Something I have come to realize recently is that a little rub at the far reaches of the travel is ok. The goal is to prevent damage. High speed bashing of the shocks is bad. Slow speed use of the shocks as bump stops during flex can be ok. Same with the tires. A little bit of rub at flex is fine as long as damage isn't going to occur. If this movement takes place at high speed, you are likely in the middle of a severe accident where none of this matters much. :)
 
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If this movement takes place at high speed, you are likely in the middle of a severe accident where none of this matters much. :)

I used to both say and believe that. Then one day someone asked me what the noise was when they hit full articulation at speed. Of course, I'm sitting there scratching my head trying to figure out how that is even possible and then he sent over the video.

Not only is it possible, it is something I would have never considered doing or that anyone else would do but sure enough, he did it.

Imagine a dirt road, mild turn to the right and back out. In the middle of the turn is a high banked berm about 6-8 feet tall. Get going about 30 miles an hour, ride up the side of the inward curved berm, turn back down out of it and keep going. Yep, hit a banked turn at speed so the vehicle is about 30 degrees off of perpendicular to the road and drive out of it. Any less speed, any more angle, and it is rolled. Get it all just right and full articulation with the front wheels turned more than you would ever guess.
 
I used to both say and believe that. Then one day someone asked me what the noise was when they hit full articulation at speed. Of course, I'm sitting there scratching my head trying to figure out how that is even possible and then he sent over the video.

Not only is it possible, it is something I would have never considered doing or that anyone else would do but sure enough, he did it.

Imagine a dirt road, mild turn to the right and back out. In the middle of the turn is a high banked berm about 6-8 feet tall. Get going about 30 miles an hour, ride up the side of the inward curved berm, turn back down out of it and keep going. Yep, hit a banked turn at speed so the vehicle is about 30 degrees off of perpendicular to the road and drive out of it. Any less speed, any more angle, and it is rolled. Get it all just right and full articulation with the front wheels turned more than you would ever guess.

Good point. My front end is still setup with the more conservative bump stopping. When I redo it all, I want to bring things closer together, but knowing and understanding how much is too close could be a little tricky.
 
Slow speed use of the shocks as bump stops during flex can be ok.
I've been thinking about exactly that. The current setup has the shocks sharing load with the bump stop at full flex. If I could have the shocks take the full load at full flex, I could get about 1/2" more up travel at full bump.

I've also been wondering if there's a way to reshape the bump stop extension so it allows nearly full shock travel in both cases.

Then one day someone asked me what the noise was when they hit full articulation at speed. Of course, I'm sitting there scratching my head trying to figure out how that is even possible and then he sent over the video.

This is a good point. Even if it's not 100% full articulation at speed, there are intermediate positions where the axle could be flexed at speed. Just hitting a pothole with the outside wheel on a freeway ramp could do it.

What do you think? Is it ever ok to let the shocks take the full load instead of the bump stop?
 
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I've also been wondering if there's a way to reshape the bump stop extension so it allows nearly full shock travel in both cases.



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Look at how Currie bumps are shaped compared to the stock cup and pad. This is a new revelation to me.
 
An LJ on about 2" of lift with 35" tires in the group I was on the rubicon with some years back wrinkled a front fender (not terrible but noticeable). Clearly didn't have bump stops set correctly so you need to be careful about how much fender contact you're willing to make. I'm not sure when exactly on the trip it happened but I could see it happening pretty easily dropping off a ledge onto uneven rocks below. She wasn't the smoothest driver ever either though.
 
Look at how Currie bumps are shaped compared to the stock cup and pad. This is a new revelation to me.
I did look at the Currie bumps, partly because I wanted to see what hardware they're using (1/2-13 bolts just like I plan to).

It's interesting that they replace the cup with a bumper. But I'm not sure how the rounded shapes would line up at full flex. Seems like you'd be hitting the lower parts of the bumps exactly when you'd want to hit the high parts.
 
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It's interesting that they replace the cup with a bumper. But I'm not sure how the rounded shapes would line up at full flex. Seems like you'd be hitting the lower parts of the bumps exactly when you'd want to hit the high parts.

Stock bumps push the axle down during articulation because of the flat profile. This is a loss of uptravel. The rounded profile of Currie doesn't do that, at least not to the same extent as the stock design. It's a detail to be aware of and one that can be exploited when you get deeper into the building and fitting phase. This is a reason I am struggling with what to do about the front fenders.
 
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Stock bumps push the axle down during articulation because of the flat profile. This is a loss of uptravel. The rounded profile of Currie doesn't do that, at least not to the same extent as the stock design. It's a detail to be aware of and one that can be exploited when you get deeper into the building and fitting phase. This is a reason I am struggling with what to do about the front fenders.
If I were feeling really ambitious, I might get some modeling clay and shape it into 3" cylinders at a little more than the prospective height of the bump stop extensions and attach them to the axle pads. Then I'd run the axle through the range of positions from full flex to full bump to press the bump stop cup into the clay at just the position where I want the cup to start taking load.

Clean that up a bit to smooth out the rough edges, and I'd have a model of an ideal bump stop extension. Then (in a fantasy world) I could model the shape in Solidworks and get it CNC'd out of aluminum to make some real extensions. Maybe they could be keyed to the four small dimples on the axle pad to get the alignment right.

I want to finish the build this weekend, so I'm inclined to stick with the two hockey pucks and a couple of washers for now. :D