2015-03-18

Jeep lift

I know a lot of my readers aren't car people. Don't worry, I've got some more non-Jeep posts coming soon. We processed a roadkill deer recently. I finally made a form of tarred canvas and I'll post about that once I get a chance to test it. I joined a grotto last weekend (a group of cavers). I just got a mountain bike yesterday, took it for a spin around the neighborhood today.

But, since I posted the others, I figured I ought to post a followup since I finally finished installing my lift. Here's the mods on my vehicle so far (in the order they were installed):
  • drains: drilled in plastic, floor plugs pulled
  • hitch reciever: like factory, forgot the brand
  • vacuum pump relo: OR vacuum pump relocation bracket
  • fenders: trim, remove liner, spray bedliner for wheel-wells
  • programming: turn signal, light timeout, acc timeout
  • spare-tire mount: teraflex hinged tire-carrier
  • highlift mount: teraflex accessory mount
  • headrests: bent back
  • CB radio: midland CB, Wilson 305-483 Silver Load antenna
  • Winch: superwinch 9500, synthetic rope
  • Winch plate: Rough Country, with D rings
  • Tires: duratrak 285/85R16
  • wheels: 4.25" backset steel
  • E-bake: pulled the bracket
  • brake lines: synergy
  • ABS sensors: rerouted and ziptied
  • diff breathers: home-grown
  • shocks: Bilstein 5100
  • rear sway-bar links: some cheap brand
  • front sway-bar links: relocated from the rear
  • springs: OEM 18/59 (ebay), replacing factory 13/55's (1.5-2" lift)
And here's what it looks like:

DSC00645 DSC00641

The last 4 items on the list are the actual lift. Overall I think this setup adds ~2" travel to one end and ~4" to the other (I forget which is which), and lifts the vehicle 1.5-2". Due to the fender trim there's no need to extend the bumpstops even running 33" tires. The shocks are just barely not fully compressed at full stuff, so I'm getting the full range of the bilstein 5100 shocks.

So, how do I like my new suspension?

Handling

The stock shocks on the sport model of the wrangler are terrible, as are the springs actually. The handling was really poor. The body pitched forward and backward when I hit a bump, and the rear end would skip really badly while cornering. It felt kindof unsafe. That's a lot of what got me doing the lift now, I had expected to wait a while. I got the bilstein shocks in an attempt to improve the handling, but with the extra droop they provided I was in danger of inverting my sway-bar, so I needed longer links to keep that from happening. I was also nervous about the brake lines and ABS sensors so I did them too.

I bottomed out (almost high-centered) not long ago while out wandering. Given that I was getting the rest I figured why not pick up some stock springs on ebay and see what lift that got me, since you can get them cheap.

I did the brake-lines and ABS sensors first, then the shocks and sway bar links. That did improve my handling, the skipping on the rear got a little better, but not nearly as much as I'd hoped. Also, the sway bars were now poorly positioned (too far from level) so my body roll got worse.

Next I did the springs and the stiffer springs made all the difference. The body pitching is gone, the back skips even less, the body roll is less than ever, it doesn't dive when I turn or brake. I love it.

Difficulty

No-one but me has worked on my Jeep since it rolled off the lot, so I did this all myself. Sorry, I didn't take in process photos like I meant to.

I did the ABS sensors and brake lines one wheel at a time, jack it up, remove the wheel, do the work, put it back together.

The hard part of this was figuring out how to jack up the car. Jacking from the front-wheel didn't work well because the steering wheel turns. Wranglers have no key lockout on the steering column. Jacking off the bumper I would get it up and at some point it would lift the other front-wheel off the ground, at that point it's sitting on just the 2 rear wheels and can fall sideways too easy, and the jack would fall over.

The solution was 2 fold. First, level the car before you start! This should be obvious, but I tried all sorts of *other* ways to compensate for the hill. Leveling the set of wheels that stay on the ground though worked wonders. Second, jack one side a little ways, throw a jack-stand under it, then do the other, jack stand, back to the first, adjust the jack-stand up. Between the two I was finally able to safely get the car up in the air with the axles at full droop and the wheels off the ground.

Note that I'm doing this to work on one end of the car at a time, leaving the other on the ground. Getting the whole thing on jack-stands would be significantly more difficult.

In theory you can install the shocks without lifting up the vehicle at all, but I couldn't get them in while compressed. With it off the ground it's much easier. The first time I did it I actually levered them in to place (compressing them) using a screw-driver so I didn't have to shift anything after pulling the stockers off. That worked prety well.

Once you can get both wheels off, the sway bar is trivial. Disassemble it, put it back together. I did notice that there's a actually a spot for a wrench next to the ball fitting, which is way easier to use than a hex-wrench.

To get the springs in I jacked the car up pretty high and pulled both wheels off. I took off one end of the sway-bar link again. I then placed the factory sissor jack (with an extra block under it) under the axle and lifted it just a bit so it wasn't hanging on the shock so I could unbolt the shock again. Then I just lowered the axle down. The axle stopped dropping at some point due to the control arm bushings, I just shoved it a bit further and popped the spring out, then popped the new one in. Jack the axle back up, reassemble everything, and then do the other end of the axle.

So, very very easy... if you can figure out how to get the jeep up on jack-stands or have access to a lift

Cost

  • shocks, ~$300
  • springs, ~$180
  • sway-bar links, ~$30
So, this comes to ~$500.0 for the lift and suspension components. Given how much it improved the ride, with the bonus of improving my entrance, exit, and break-over angle and significantly improving flex, I'm pretty happy with it.

When I went looking for kits that get those gains with only a small lift all I could find were kits advertised as e.g. a 1.5" lift that actually lift it more like 2.5" and cost more like $1500.

Planning a lift

It took me a lot of research and thinking to figure out where to *start*. On the Tacoma this was pretty simple as it's independent front and leaf-spring live-axle in the rear, but Jeeps use a live-axle coil suspension which makes for a lot of different moving pieces. All of the components need to work together. If you're planning a suspension modification I have a suggestion: Start with your tire size and how much you want to trim fenders/bodywork/etc, and let that decide your bumpstop.

Once you have your bumpstop height, everything else chains from there. That's because your bumpstop height decides how long a shock body will fit when everything is fully flexed. You need to hit the bumpstop and not the shock body, so you want a shock that's just a little bit short, that way you get to use all the travel the shock gives you.

Once you've chosen your shock, your shock is likely to be the limiting factor on your droop. Now you can use your maximum droop to decide how long your spring needs to be uncompressed. If the spring is shorter than this you'll have to limit your flex by attaching the springs to the axle and the vehicle, or using limit straps. The droop is also what matters for brake lines, breather tubes, diff locker wires or air-tubes, exhaust relocation, it's a factor for driveshafts, etc.

Now that you're picking your springs you can figure out normal ride height. Note that nothing above was impacted much by ride-height. You can have the normal ride be basically anywhere in that travel . It's just a matter of how stiff your springs are.

Now you'll want to pick sway-bar links that accommodate that droop, but also come out near level at your normal ride height. You may have to give up on getting them level.

If you're going more dramatic you may also need track-bars to recenter your axles, this is mostly based on normal ride-height, but may be impacted by trying to avoid tires hitting the body at full flex. Driveshafts are also mostly based on ride-height, since they get most of their wear at normal angles, but I'd imagine that not having them bind too badly would still be important even with a low ride-height and a lot of droop. Control arms are based on ride-height as you need them to correct camber, and that's all about highway driving.

I'm not expert in the area, and you may note I didn't do ANY of the complicated stuff... but I found this model to be a useful way to work through planning a lift. The internet would have you thinking that tire-size decides your ride height, and everything else stems from there. But ride-height is actually one of the more independent variables, while bumpstop is really solidly fixed by tire-size and fenders, and due to shocks a lot stems from that.

Just a thought.

Conclusions

While I definitely used the large knobby tires this winter to get in and out of the driveway (and get Jess truck unstuck once), I haven't taken old blue offroading since I did the lift (I finished it last weekend). So, I'm really curious to see how it all performs. I can't use all my flex right now since I don't have sway-bar disconnects. I believe that the sway bars will lift my wheels off the ground even though I have suspension play left, so discos will likely be the next purchase. I'd rather get a more multi-setting front sway-bar, but those are *expensive*, so I'll probably just do discos for now.

DSC00639

Overall the lift was pretty cheap, it handles far better than it did on road, and it should be strictly better off road. So, I'm really happy with it. It's also always fun using things you've really spent some time and energy on. A car is no exception. I'm looking forward to getting it on the trails again... possibly this weekend!

UPDATE

Later on I did adjust my drag link, by about 1/8 of a turn. This corrected my steering wheel by maybe 5 degrees, probably less. I did this by taking a 15mm wrench with me and driving back and forth down a stretch of fairly straight highway, and just tweaking it until I found just the right setting.

Also, I've now taken this setup off-road, and indeed it performs very well, I'm extremely happy with it. I think the height came out just right, significantly improving break-over angle. I bottomed out once, and that was on my diff, so that's a matter of tire-size, not lift height.

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