Aluminum Control Arms

BXSS · Post by **BXSS** » Mon Aug 25, 2008 7:03 pm

I just installed aluminum control arms + Whiteline RCA + MOOG inner tie rods on my OBS-T this past weekend & have these notes on installation.

1. Make sure the aluminum control arms you get have ball joints on them as you will need the sleeves that go between the alloy arm & ball joint itself on any ball-joint you use - Whiteline RCA kit instructions say re-use the sleeve with their ball-joint (steel arms do not have these sleeves).
I had 1 side of the suspension apart only to find out I was missing the sleeves so I had to put everything back together & order the sleeves part # 20216fa000 - I paid $36 shipped for the pair from Boxer 4 Racing

2. The sway bar links are also slightly different on the alloy arms vs. the steel arms so make sure you get those too.
My Whiteline links looked a little too short to mount on the alloy arms, but I had a Cusco front sway bar with links in my garage so that was no big deal.

3. Each alloy arm is only 1.5lbs lighter than the steel arm (you'll loose 3lbs with the pair of arms) so if you thought you were saving 10+lbs you are wrong - I know I was...

My first impressions are sharper/quicker turn-in - not sure if that is do to the RCA kit or the alloy arms or the combination of the parts.
If you are missing any of the above parts negotiate $$$.

93forestpearl · Post by **93forestpearl** » Tue Aug 26, 2008 6:00 am

Crazy. I'm surprised they are that heavy.

BXSS · Post by **BXSS** » Tue Aug 26, 2008 12:35 pm

So was I....

The steel arms are hollow so even though they look big & bulky they really aren't.
The alloy arms are solid so although they look slimmer they are still pretty fat.

I can't remember the component weight as I was just paying attention to the difference in weight but I think the steel arms were 10.5lbs each & the alloy arms were 9lbs each.
Net loss = just 3lbs.

Post by **Legacy777** » Tue Aug 26, 2008 6:07 pm

Yeah....weight-wise, the aluminum arms were never meant as that much of a savings. I think they may be a little more rigid then the steel arms....but at what point are you splitting-hairs.

skid542 · Post by **skid542** » Tue Aug 26, 2008 6:16 pm

Thanks for getting some actual weight numbers posted Carlos. I've always been curious what they were.

I think Josh is right that the biggest difference is stiffness. But as you probably know, hitting a curb with steel arm and an Al arm will have two different outcomes... You will probably still be able to drive home on the bent steel.

BXSS · Post by **BXSS** » Tue Aug 26, 2008 6:27 pm

Yeah, I also believe the "upgrade" factor of these is their rigidity.

As for curbs I try to avoid them whenever possible but I tend to believe the car will not be drivable in the event of an impact with one!

n2x4 · Post by **n2x4** » Tue Aug 26, 2008 6:44 pm

BXSS wrote:Y I tend to believe the car will not be drivable in the event of an impact with one!

In my experience, this is correct. Throwing my first legacy in a ditch at about 40mph due to a spin out resulted in a crushed rear control arm bushing and a bent arm. Interestingly there seems to be a built in "weak" zone in the metal arm right at the spot where there's a big open hole on the underside.

I've seen several arms bent in this exact same spot. Unfortunately, the bend is bad enough that the tire is wedged in the wheel well.

93forestpearl · Post by **93forestpearl** » Tue Aug 26, 2008 8:49 pm

IIRC, nailing a curb or something with the aluminum arms will bend the hell out of the mounting points, leaving you with much more work to fix it. One would hope that the Al arms would simply break in the event of an impact.

skid542 · Post by **skid542** » Wed Aug 27, 2008 3:10 am

Dan, did you mean the steel arms will bend the mounting points versus the AL which will simply break? You reference aluminum for both senarios?

Post by **Legacy777** » Wed Aug 27, 2008 7:01 pm

No, he was talking about the aluminum arms bending the steel mounting points on the crossmember and/or frame.

BXSS · Post by **BXSS** » Wed Aug 27, 2008 7:43 pm

I'm keeping my distance from curbs now!

skid542 · Post by **skid542** » Wed Aug 27, 2008 8:39 pm

Ah, okay, I'm following now. I must have been brain dead yesterday. I thought Dan was comparing the steel vs. Al.

Now? I thought we were always supposed to keep a little buffer between us and the curbs

.

93forestpearl · Post by **93forestpearl** » Thu Aug 28, 2008 2:30 am

I don't know for sure guys. I just remember reading (or hearing, i dunno) that Subaru made the early control arms really strong and that they would mangle the unitbody before the arms broke. Since those early ones that Carlos just put on a pretty heavy, they may be that strong. I suppsoe the only way to find out is to go nail a curb at speed, but I don't think he's willing to be the guinea pig on this one

evolutionmovement · Post by **evolutionmovement** » Thu Aug 28, 2008 2:52 am

I would definitely think they'd wreck the corssmember/frame mountings before damaging the control arms - the things look and feel tough as hell - much stronger than the steels. They're solid alloy, but the grid that makes them up looks built to handle extreme stresses. I haven't driven the car since I installed them and would forget at this point what it felt like before (plus I had been driving with a bad tie rod), but I suspect it's about the last mod to make if you bother at all. Does look kind of cool if you can see the underbody of the car from the front, say you're approaching it while walking up a hill or something.

entirelyturbo · Post by **entirelyturbo** » Sun Aug 31, 2008 5:26 pm

What car were the Al arms originally intended for? 1st-gen Impreza or 2nd? If 2nd, were they for the sedan or wagon?

evolutionmovement · Post by **evolutionmovement** » Sun Aug 31, 2008 6:15 pm

Mine were first gen, I was told. They fit fine, only needing to grind some of the metal of the forward bushing to get it to fit the Legacy turbo x-member.

entirelyturbo · Post by **entirelyturbo** » Sun Aug 31, 2008 9:58 pm

If you had to grind the bushing sleeve, they're for a second-gen, or the bushing was swapped.

And if they were for a second-gen sedan, then your track got wider also.

evolutionmovement · Post by **evolutionmovement** » Mon Sep 01, 2008 12:28 am

Certainly looks no wider. If it were wider, I think it would rub anyway unless the increase is negligible.

Aerotech · Post by **Aerotech** » Mon Sep 01, 2008 12:45 am

Not the track, but the mount points for the sway bar are wider apart, definitely. I broke one of the Perrin endlinks I was using because the angle was so extreme. I just put in a Tribeca swaybar, and it lines up perfectly above the AL arm mount points.

evolutionmovement · Post by **evolutionmovement** » Mon Sep 01, 2008 2:50 pm

Yeah, you definitely need new links or something. Completely forgot about that. I'll need those to get the wagon going again, too.

BXSS · Post by **BXSS** » Tue Sep 02, 2008 2:32 pm

I used GC8 Impreza arms on my OBS-t (GF8 - same crap as a GC8).

My Whiteline swaybar links did not look like they were going to fit easily with the alloy arm swaybar mounting points.
I just took them off & used a set of metal swaybar links I had on a Cusco swaybay.
I'll eventually make a set of pillow-ball links but these will get the job done for now & are not PLASTIC!

I figured I'll use the Whitline Links on the SS so both cars get an suspension upgrade (assuming the SS front links are plastic - I can't remember)....

t3h L3g4cy · Post by **t3h L3g4cy** » Sun Oct 05, 2008 4:24 am

I don't know for sure guys. I just remember reading (or hearing, i dunno) that Subaru made the early control arms really strong and that they would mangle the unitbody before the arms broke. Since those early ones that Carlos just put on a pretty heavy, they may be that strong. I suppsoe the only way to find out is to go nail a curb at speed, but I don't think he's willing to be the guinea pig on this one

I'll be the guinea pig haha. Well not really...I had hit a curb, 2 years ago, in excess of 40mph and it screwed up my right front side. I ended up popping the tire, scratching the rim, bending the control arm, and bending the right front fender. Somehow I managed to save the rim. I'm writing now because ever since then I've had problems correcting my alignment. I must have done the alignment at least 5 or 6 times in september. I'm not quite sure if the control arm was the super heavy one that would bend the frame or unitbody before being bent itself. I think the right front control arm mounts are bent or warped because i know the toe is 0 all around this time. The car still pulls to the right slightly. All tires are filled to 34psi. Caster is in the green all around on the alignment and camber is marginal only on the right front. It's right between green and red.

So how would I fix this? Is this something I can even fix? Thanks in advance guys.

93forestpearl · Post by **93forestpearl** » Sun Oct 05, 2008 5:47 am

Did you have the aluminum arms on?

About 4 years ago I nailed at field entrance at 35 mph and it bent my control arm, but I've had no such issues since replacing it.

t3h L3g4cy · Post by **t3h L3g4cy** » Mon Oct 06, 2008 3:27 am

the posts say that steel arms are hollow and the control arms on my car have some holes... is that u guys are talking about? the drilled holes on the control arms? if so then no, i have steel control arms.

Btw i was checking the tread on my tires and kicking the tires. I noticed that in the front, especially the front right, it makes a clunking noise when i kick the tire. Like metal on metal clunking... I kicked the tire in the 9 o'clock and 3 o'clock locations. Does anyone else have a noise when they do that?

t3h L3g4cy · Post by **t3h L3g4cy** » Thu Oct 16, 2008 6:58 pm

Well it turns out that the clunking noise was the hub bearing wearing out. Me and my dad tried to replace it but the bearing housing got stuck in the spindle. We half assed it hoping that it would be better, but it turns out it made it worse. so the car sat in the shop for a couple days.

We got a used 94 legacy spindle and there's no play in the bearing now.

My alignment problem still persists tho. It pulls to the right a bit even tho the alignment machine reads 0 toe all around. Camber and caster are in the good range too. If i just overhaul the suspension completely do u think it'll help with the alignment? It's probably in need of new struts and springs anyway. I don't know if the previous owner(s) ever replaced them. If u guys think that i should get new suspension for my alignment problem i'll pose the question under an appropriate thread. Thanks for ur help

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Aluminum Control Arms

Aluminum Control Arms