Cracked classic 900 lower control arms.

[DeLorean]

Just a "keep on the lookout for!" I know this IS a fairly well known problem, which I had always kept an eye on, but today upon a real close inspection I found the crack on the rear of the driver side lower control arm. Cleaned off the paint, and it is in-fact cracked clean through the arm (brake clean passes right through it), right by where it's welded with probably only about 30% of the structure of the A-arm hanging on there. This is NOT a rusty A-arm, it is very clean. This is all due to metal fatigue. I will say, this arm IS probably an original, and has 280,000 miles on it.

Kind of scary to think of if that had let go coming into turn 6 at 120 MPH

So I am wondering. Durability / reliability of the scantech classic 900 LCA replacement units? Are they going to stand up to track use, or should I re-weld, and plate the stock lower control arm?

[DeLorean]

my crack looks almost exactly like this-

[SwedeSport]

I would just have that one blasted, weld up the crack, and reinforce it with a plating kit.

[DrewP]

We used to send cars around the corner to the muffler shop we used to have them weld little tabs straddling the crack (or the area where they would crack).

I have no experience with the aftermarket arms, I have a stack of good original ones, but I will definitely check my cars out closer this week.

[Jordan]

The aftermarket ones seem like they are of good quality.

[DeLorean]

The aftermarket ones seem like they are of good quality.

I am taking your word and quoting on this! If I am killed on track from a scan-tech LCA failure I am blaming you!

(kidding of course... but if it actually happens now you'll feel guilty at least!)

[SwedeSport]

It would give you some cheap insurance to box that new set.

[gmreider]

Maybe we should put a cage and better padding in your car also ?
Might be better insurance than a eEuroparts warranty claim on a defective A arm!
We probably should all have Hans devices too.

[Luke]

It would give you some cheap insurance to box that new set.

+1

[DeLorean]

Gary, it it gets much faster (which it will with the planned improvements) a full cage might not be a bad idea... There are a whole lot of trees with the bark blown off of them at the hills...

[DeLorean]

I just checked out my winter beater / rally-cross loaner car, and it is perfectly clean, no cracks no signs of stress.

[RadioFlyer]

Lazy man's question... can you weld in the control arm supports from underneath without removing the control arms from the car? Just jack it up, clean and blast, and weld? Or would you need to remove them first?

[DrewP]

Little tabs on the side you can do in place as long as you're fast with the welder, or it could overheat the bushing.

For boxing them in I'd expect you'd put in quite a bit of heat, but you could move around and let them cool and it'd probably be fine.

Removing the lower control arms is pretty painless though, unless your car is real rusty or something (advocating for the slightly less lazy but more time consuming approach.)

[squaab99t]

Lazy man's question... can you weld in the control arm supports from underneath without removing the control arms from the car? Just jack it up, clean and blast, and weld? Or would you need to remove them first?

Not to throw rocks, but if you are taking that much care to weld pivots and box why not do it right and pull them? Proper painting will save you heart ache in the long run. For me the only way to TIG weld very good is on the bench.

[RadioFlyer]

Fair enough. I'll probably end up taking them off. Could use paint anyway.