Mounting new ball joints? Racing Suspension experts please.

[Guest JAMIE T]

I'm thinking about boxing my front control arms(for appearance and strength). This is alittle hard to explain... The stock configuration... Bolts go through the TC rod, through the ball joint, then throught he control arm and are nutted. Then two more bolts are bolted from the bottom, through the control arm and thread directly into ball joint.

 

I want to weld nuts under(inside) the control arm, and drill the threads out of the ball joint, and bolt the ball joint from the top only. Threading right into the captured nuts.

 

I will leave a hole just large enough on the under side to attach the sway bar, but otherwise I want a smooth street rod quality control arm.

 

OR, if that sounds absurd or irrational...

 

How much strength will I be giving up, if I just cut the lip that runs around the bottom edge(were the bottom boxing plate welds to the upper half), and welding up the seam(of course, then grinding it smooth). To clarify, I won't be cutting the "channel", just the edge that flares out. Then welding the leftover seam solid.

 

And furthermore, if you are wondering why I'd be so anal as to even worry about doing this mess in the first place, it is becuase I'm modifying the control arms anyway to make them adjustable, so I figured why not make them look great while I'm at it. Ya know? That's the way I do things.

 

I originally considered building new control arms made of aluminum, but figured I'd get flamed for even suggesting it, even though I'm sure they would hold up just fine. 6061-T6, fully tig welded. My ONLY concern was the threads in the aluminum for the 3/4" turnbuckles pulling out under heavy(and I mean HEAVY) side loading. Any thoughts on that?

[Pop N Wood]

Corvettes use aluminum suspension parts, so if done right I have would have no worries.

 

It is the "done right" part that is worrisome.

 

I have to admit I don't have a good mental picture of what you are trying to do, but I can say it would scare me to no end. This isn't an area where you can afford a failure of an untested component. Chevy has buildings full of metallurgists, engineers and lawyers. Guys like you and I have a welder, a hammer and a pile of 30 year old car parts. I am not saying don’t do it, but I would seek out a competent machinist and run tests of some kind before I would drive on modified suspension components like that.

 

You know I look at some of the adjustable control arms shown on this site and I think I could easily make that for less money. But there is something to be said for buying something that has stood the test of time. The parts don’t seem quite as expensive when viewed in that light.

[johnc]

I want to weld nuts under(inside) the control arm, and drill the threads out of the ball joint, and bolt the ball joint from the top only. Threading right into the captured nuts.

 

I don't think the top surface of the ball joint mounting flange on the ball joint is machined parallel to the bottom surface of the ball joint mounting flange. You would need that done to ensure the bolt head is square and true when torqued to spec.

 

You'll also need to ensure that the welded on nuts are centered properly and no lateral torque loads are applied to the ball joint mounting flange when the bolts are tightened. Remember, that flange is a casting and is designd to only take compression loads on torque down.

 

How much strength will I be giving up, if I just cut the lip that runs around the bottom edge(were the bottom boxing plate welds to the upper half), and welding up the seam(of course, then grinding it smooth). To clarify, I won't be cutting the "channel", just the edge that flares out. Then welding the leftover seam solid.

 

Don't know. Are you planning on racing the car?

[gramercyjam]

Corvettes use aluminum suspension parts' date=' so if done right I have would have no worries.

[/quote']

 

Yes, but they aren't welded, they are cast or forged. Welding will anneal 6061-T6.

[Pop N Wood]

Corvettes use aluminum suspension parts' date=' so if done right I have would have no worries.

[/quote']

 

Yes, but they aren't welded, they are cast or forged. Welding will anneal 6061-T6.

 

Sort of the point I was trying to make. Lots of different types of aluminum. The type you can weld doesn't have the same properties as the stuff you can't. The upshot is you had better know what you are doing.

[JMortensen]

One of my dumber moves was to cut the trans crossmember for clearance for my exhaust, which is tucked really tight underneath my Z. I just cut the lips that fold down on the sides (not all the way, just about 1/4", and then I braced it with a 1" x 2" strip of 1/8" plate on the top and bottom of the crossmember where I had cut it. I snapped it in half like a toothpick a couple months later. I am not an engineer, but I think the folded areas on the crossmembers and control arms are IMPORTANT. Really important.

 

Also, if the ball joint were to somehow come loose it would be captured in the end of the control arm. With your idea the strut could "fall off" the control arm. I wouldn't risk it, since the entire braking load will be put through the 4 bolts that connect the ball joint to the control arm, unless you have some sort of lip on the ball joint that sticks through the hole in the control arm.

 

I have swaged aluminum ended 3/4" TC rods and haven't had even the slightest problem with them, so I don't think that your "pulling the threads out of the aluminum" idea on an aluminum control arm would be a concern.

 

Jon

[Guest JAMIE T]

Guys like you and I have a welder, a hammer and a pile of 30 year old car parts.

 

Guys like you and I have a welder, a hammer and a pile of 30 year old car parts.

 

You know I look at some of the adjustable control arms shown on this site and I think I could easily make that for less money. But there is something to be said for buying something that has stood the test of time. The parts don’t seem quite as expensive when viewed in that light.

 

I think that is a compliment considering I've built some of the sets you're talking about. But, for mine, I wanted something differant. I'm a guy with a welder who uses it 8 hrs a day, 5 days a week, (and sometimes more if I need to work on my car)to weld ALUMINUM, and steel.

 

Remember, that flange is a casting and is designd to only take compression loads on torque down.

 

My ball joint flanges are forged, they have a wide parting line indicating they are not a casting.

 

You would need that done to ensure the bolt head is square and true when torqued to spec.

 

Holy crap! Do you really "Torque" your suspension bolts? Like, with a torque wrench? I'm talking about some lock tite and a heavy tug. Really, I'm not being sarcastic, but I've never used a torque wrench when assembling suspension. Granted, I'm not a pro race car dude like you. As for the "square" bolting surface, they are probably parallel enough for lock washers. Do I plan on racing it? I'd like to if time ever permitted.

[johnc]

Holy crap! Do you really "Torque" your suspension bolts? Like, with a torque wrench?

 

Absolutely! Why would a suspension bolt require any less attention then a head bolt. In fact, a failed head bolt costs you money while a failed lower control arm bolt could cost you your life.

[Guest JAMIE T]

LOL, I was just teasing. It never really occured to me to torque suspension bolts, cross member bolts, diff mount bolts etc... That is until you brought up that valid point. We can always count on you to enlighten us and help improve our appreciation for technically savy builders. That is the differance between racing for fun, and racing to win.

[j260z]

who needs a torque wrench!! i just tighten up the bolts until they strip and then back them off half a turn!! LOL

 

sorry, i couldn't resist.