Simple DIY Rear Lower Control Arm Upgrade

[Jetboy]

So... I bent a rear LCA a while ago. Finally got around to upgrading them and straightening the damaged one. Thought I'd give a little updated on how I did them. It's dead simple. I used 1.5x.75 channel. It's ~.125 wall thickness. Cut with 45* angles on both ends to a length of 25.25" (double check before you cut)

Clean up the welding areas with a grinder. (I prefer a sanding disk over a flapper for this, but do whatever you want.)

Then simply weld into place. Continuous welds are not necessary. Stitched welding is just fine. I'm not really sure why I welded the entire sections. I guess I wasn't thinking about engineering, just burned them in. Also you should press out the bushings. I'm lazy and left them in and welded a little less heat around the ends. Not ideal - but they're a bear to press out once they're rusted in place and I was lazy.

Total time took about 2hrs. I big part of which was waiting for them to cool enough to paint.

Finally you can leave the brake line bracket in place- but you'll need to notch the bracket with a cutoff disk to fit the flange of the channel. Then weld it all together.

I intended to do both top and bottom - but I tested with one side done with a jack under the center and it supported the weight of the vehicle without a problem, so I'll test as it is. If if needs more strength you can always repeat on the top side. too.

 

[wfo9]

Not a bad idea...

Just be careful welding those things.. They are paper thin if I remember correctly.

 

[Jetboy]

They're thick enough to weld pretty easily without burning through. Maybe 2mm? But they must be made out of playdough or something. They bend really easily.

My intent was to simply re-tube with maybe 1.5 x .250 ish tube, but I had this channel left over and it fit so well I just went with it. If I bend these I'll probably replace with some adjustable ones. Once you start buying joints - it's not really worth it to build them yourself. The cost of the joints is as much as just buying complete arms that are already done.

Compared to an 80 series control arm I have cut apart - the 4runner ones are super wimpy.

 

[honda250xtitan]

Nice. i thought about building my own with Heims. then it got hot af here in az. They're glorified traction bars, which i've built many a set.


Would pressing out the bushings, drilling/tapping a hole for a grease zerk and using polyurethane or even delrin bushings be doable?



You should have some fancy CNC logos made up and build a few sets and sell them....lol. Market them as "overlanding LCA's" they'd sell like crazy on IG.. lol

 

[Inv4drZm]

Welding the whole thing might be nice to keep the water and rust out.

You could also use a piece of angle iron, might be easier to find.

 

[tackleberry1145]

Welding the whole thing might be nice to keep the water and rust out.

You could also use a piece of angle iron, might be easier to find.

Yep, this. A guy over on the FJ forums did the same thing a few years ago.

 

[Jetboy]

Nice. i thought about building my own with Heims. then it got hot af here in az. They're glorified traction bars, which i've built many a set.


Would pressing out the bushings, drilling/tapping a hole for a grease zerk and using polyurethane or even delrin bushings be doable?



You should have some fancy CNC logos made up and build a few sets and sell them....lol. Market them as "overlanding LCA's" they'd sell like crazy on IG.. lol

I think you'd be better off to just start with a fresh piece of tubing for the bushing ends. There's a few places that sell a complete weld in kit for the ends. You could press them out - but it's probably some weird size that wouldn't fit anything off the shelf.

My issue with poly is that it has very little flex to it. For sports cars I'd be all for it. But for offroad trucks, that little amount of cushion can make the difference between a broken axle or a broken pinion. Kinda like the difference between a rigid strap and a kinetic strap. So I like having the rubber bushings.

Should be really easy to make some out of heavier tubing though. If I had more time to plan and wanted better ones - I'd probably put a threaded rebuildable heim in one end and keep the OEM rubber on the other. A pair of these is $70. https://www.speedwaymotors.com/QA1-...A_ZvIbBMELvkkiJw3COa2d2Uaidw8w0UaAhFlEALw_wcB Plus some weld on threaded ends and tubing. You could save a few bucks building them. I'd double check the width though. I don't remember the exact spacing of the brackets.