See any reason this won't work? Lower control arms.

I wanna replace my control arms with something stronger, more reliable, with more control (I'm death wobble-phobic and I thought these would help... or at least make me feel better). Stock height which is why I went with stock-type bushings and not johnny joints on one end. The material is schedule 40 structural pipe and 1.5x2 .125" rectangle tube. I wanted to run this design by you guys to get some input and make sure they'll work well for what I'm goin for before I have them built, this is my first attempt at control arms. These are the lowers, the uppers will be exactly the same minus .75" in length. So whatcha think? Good to go?

Several problems here.The square tubing would bind on the shock mounts(if lifted).You will also need to purchase bushing cradles from JKS or Rocklogic,etc,you could turn your own but finding the right size(SEAMLESS DOM) material is tough(I bought several feet of it when I did my first set,still cheaper to buy the cradles).If your going to the trouble to build them you should at least make one set adjustable for castor/pinion angle adjustment.
Not a "must" but a great time to beef up the pass axle mount,makes changing bushings a breeze,just grab one more upper cradle.

Bushing sleeves are available from a variety of vendors. Hit up Dan at RuffStuff Specialties.
http://www.naxja.org/forum/showthread.php?t=961917

Wouldn't wj arms be better and cheaper...... and easier.

I pretty much suck.

dragthatsht said:

Wouldn't wj arms be better and cheaper...... and easier.

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x2

might be a dumb question, but,...

Have you damaged a stock arm? I've seen a (very)few bent/torn up LOWER control arms, usually by dragging them over/slamming them onto rocks. ('never seen a torn up upper) They're up for any other abuse.

How would you get "more control" using any material and the stock bushings? The stock arms will twist slightly when you flex the suspension, but most of the play in the stock suspension design is from the bushings(that's what they're for)

You're worried about death wobble. Do you have DW now? If so, changing your arms isn't going to stop it. DW at stockish lift heights is caused by worn components. The control arm bushings are not often the culprit(even if they're worn)

That's my thought on the design idea. As far as the design engineering:

What are the holes in the top/bottom of the arm material for? The arms are going to be subject to twisting forces, and those holes are going to be weak points where cracking will start(not "might", "will")
As stated above, you may have problems finding suitable sch-40 material to make the bushing cups.
Other then that, it looks like a standard non-adjustable design.(Not an insult, there's not much you can do with non-adj lowers - they're pretty simple)

If you build these, I'd say don't include the holes, and have fun, but they're not going to stop DW, and you don't really need them unless you're beating up the stockers on rocks.

RCP Phx said:

Several problems here.The square tubing would bind on the shock mounts(if lifted).

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Milford Cubicle II said:

Stock height which is why I went with stock-type bushings and not johnny joints on one end.

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RCP Phx said:

You will also need to purchase bushing cradles from JKS or Rocklogic,etc,you could turn your own but finding the right size(SEAMLESS DOM) material is tough(I bought several feet of it when I did my first set,still cheaper to buy the cradles).If your going to the trouble to build them you should at least make one set adjustable for castor/pinion angle adjustment.

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The OD of the poly bushings I'll be using is 2" which will fit the 2" ID of the sch. 40 just fine with some lube, a press, and maybe a BFH

And as far as adjustability goes, they'll still be adjustable via shims (even though I've never had to and shouldn't have to if these turn out to be right at 15.75" each)

dragthatsht said:

Wouldn't wj arms be better and cheaper...... and easier.

I pretty much suck.

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Yes.




Lol but I can't find any and this is way more fun. And it's not like I have tire rub issues. But if I found a set I would most definitely go for it for the lowers.

tbburg said:

might be a dumb question, but,...

Have you damaged a stock arm?

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Yes

tbburg said:

You're worried about death wobble. Do you have DW now? If so, changing your arms isn't going to stop it. DW at stockish lift heights is caused by worn components. The control arm bushings are not often the culprit(even if they're worn)

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No offense but this isn't a death wobble thread. Unfortunately I'm fully aware of the nature of death wobble and what role the CA's play in it. Sorry, I'm a little bitter as you can tell I've literally replaced every front end component and I still have it :banghead:I suspect that one component has worn out before I got the rest fixed and the death wobble at bay so I'll just have to find it and replace it again.

tbburg said:

As far as the design engineering:

What are the holes in the top/bottom of the arm material for? The arms are going to be subject to twisting forces, and those holes are going to be weak points where cracking will start(not "might", "will")

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The holes are to keep the inside of the tube dry. And they were offset and spaced in the top and bottom planes specifically to not be susceptible to twisting stress. Also, being .125"R in .125" steel, even if they were place right in the middle of the arm they wouldn't have an appreciable effect on strength.

tbburg said:

As stated above, you may have problems finding suitable sch-40 material to make the bushing cups...
If you build these, I'd say don't include the holes, and have fun, but they're not going to stop DW, and you don't really need them unless you're beating up the stockers on rocks.

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Like I mentioned above, I've already found the sch. 40 that will work so that's no problem. And I might not include the holes, if I can find anyone that will tell me that I won't have rust issues from the lack of ventilation inside the tube. But so far I've been told that they're a good idea :dunno:

And one of my lowers is bent, which would definitely contribute to DW.

tbburg said:

Have you damaged a stock arm? ('never seen a torn up upper)

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now you have. I have a habit of breaking things

Yeah, well, Grim, you don't count. You could probably break a hammer with a pencil eraser,

Milford Cubicle II: I wasn't trying to get on to DW, I was responding to what you wrote:

I'm death wobble-phobic and I thought these would help... or at least make me feel better

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That's all.

As far as rust inside the tube, somehow moisture always seems to find a way in. Whenever I'm making a ( supposedly ) closed metal structure, rather then use weep holes, I usually close everything up, then poor a small amount of used gear oil inside before making the final weld. The final weld seals the structure. I've never had cause to open up any of the bumpers/sliders/etc I've made that way, so I can't say for sure how well it works.

In tub/fabric aircraft, they drill small holes between all the tubes on a frame, then after welding, fill the tubing with hot boiled linseed oil, rock the assy around to coat everything, then drain the excess oil out. Pain in the a**, but it works. Some of those airframes have lasted 3/4 of a century without significant internal rust.

Interesting...

The question is, is that over kill for control arms on a jeep with ~250k miles? Probably, but then again I do intend on keeping it for another 250k

I wonder if those moisture absorbing packets that they put in beef jerky bags would do a good job?

Have you changed wheels in an effort to cure the DW that's where I finally found mine

I pretty much suck.

Wheels? Last time I checked my runout it was good...

What am I looking for?

A friend and i both have had a set of wheels that that balanced out but caused death wobble for some reason. Pulled them and it went away find a friend that has wheels that work well on his rig and run them on your rig and see what effect it has. I have seen tires cause it as well.

I pretty much suck.

You wont like Poly bushings thats why I assumed you meant stock rubber bushings.Poly bushings in a rigid arm can actually damage/break your ca mounts.

I've had poly bushings for over a year now and I like them. And obviously I already have them so I'm just going to save some money and re-use them.

Sorry, I forgot to mention that I already have the bushings.

first. I second making them adjustable even if you dont need it now, what if you decide to do a BB later or even go 3 inches.
Johny joints or some kind of flex joint on one side could actually help slow down the wear on the bushings at the axle side(if thats what your worried about)

I have also seen stock control arms fail many times. (usually the uppers)

my question. So are you planning on making custom axle mounts for the upper control arms?

No this is stock stock stock height and it's staying that way lol. But if I did lift later then I would just build new ones.

Going adjustable would make this a LOT more expensive anyways, right now it's cheap cheap cheap which is the way I like it.

And no, I'm not making custom mounts for the uppers.

The axle end of the UCAs are "female" ( a U shape) Your design has "Male" / bushings at each side of the axle and you said the uppers were gonna be EXACTLY the same as the lowers, just shorter. How is this gonna work?

You're right, I shouldn't have said EXACTLY. To be honest, I haven't looked at the uppers very hard yet.

tbburg said:

might be a dumb question, but,...

Have you damaged a stock arm? I've seen a (very)few bent/torn up LOWER control arms, usually by dragging them over/slamming them onto rocks. ('never seen a torn up upper) They're up for any other abuse.

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saw this...

GrimmJeeper said:

now you have. I have a habit of breaking things

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... and was gonna say this :yelclap:

My uppers, after some fun on the rocks with my 96 - no jeepspeed shenanigans involved, because there are too many trees around here.

Jeepman401 said:

Ken's upper control arms after the first rock garden

I go through, and park to watch everyone else go through, and just as I stop, I look in the rearview in time to watch Ken bouncing from rock to rock, to a tree, and back to some more rocks.
Unfortunately none of my video came out.

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That being said, I did go through a rock garden, uh, enthusiastically enough to make a spare unit bearing go from sitting on the floor behind my spare tire on the passenger side to flying through the driver side rear quarter window. Picking that glass up sucked.

I have never broken a stock LCA though. I carry a full set of spare control arms at this point, along with tools to install them.