Gang,
Just took delivery of a complete set of control arms from a mid-60’s big car. Mine are good, but these parts are getting scarce and I wanted a get/rebuild a set of spares. Turns out the uppers on this set of spares has the original riveted upper ball joints. I’m hoping this means they low mileage relative to my 360,000 mile 98 or 230,000 mile Starfire. Yeah, low mileage…

I have confirmed Hotchkiss has no interest in making extra-strong custom replacements for Mid-60’s big Olds cars. No market, understandable. Moving on to boneyard replacements:

Not my first rodeo, so my plan is to
1) get the A-arms cleaned & magnaflux checked for cracks - I will discard any with cracks or irreparable out-of-round bushing shoulders.
2) reinforce the lower arms around the ball joint with a custom welded steel plate. I’ve broken lower ball joints in the past and never want to have this happen again. Ever.
3) replace the ball joints and bushings per factory recommendations
4) get them cosmetically refinished in satin black or something that looks decent. Ideally solvent resistant.

If these arms wind up better than what I’ve got, they go on the car. If not, they’re in reserve.

Here & there I watch the lowrider hydraulics guys & immediately think that they must know about how to strengthen stock suspensions. I don’t want to bounce my cars, but I really admire the strength they can build in which allows those cars to do the crazy 3 wheel & bouncing stuff. Not my style, but the engineering sure is interesting.

My advice on these topics has been almost exclusively local, so I’ve got what I think is a good plan, but I’m not sure it’s the _best_ plan.

Am I missing some points here? Do you have suggestions and/or vendors to help me make bullet proof control arms? Looking forward to your thoughts & sugestions.
Chris

 

Sounds like a plan. I don't think magna fluxing is necessary as you can usually visually inspect them. since you got that many miles on your originals why do you think you have to go through great lengths for the new set? I'd just rebuild them stock using Moog parts and replace the old ones as required.

 

Eric,
My originals have been similarly modified two to three decades ago. They’ve worked great. So I’d like to repeat the success and improve, if there are smart moves I haven’t heard about yet.

Magnaflux checking may be overkill, but it’s cheaper than body work from a lost wheel & for sure cheaper than healthcare bills for anyone who gets hurt.

My 98 has rebar welded in around the lower ball joints. My Starfire has full triangular supports around the ball joints to about 1/3 of the width of the lower arm. Never a problem since then, but I don’t want to replace them with anything weaker.

My theory (unproven) is that latter-day replacement ball joints are just a thousandth or 2 too large in diameter. Lack of precision in machining may cause stress cracks from the interference fit - eventually causing failure on the lower control arms. I’ve always aimed for USA made parts, generally Moog, but I’m not sure the guys doing the work were as picky as me. Offshore parts could be in my cars.

Plus my Starfire is making A-arm clunking sounds which I really don’t like. Especially at 70 mph. The arms I have on the car may be wearing out of round, so why not have a spare set as an option?

Just want to make sure I’m doing everything I can to make these cars as safe as possible.

Many thanks for your thoughts on the plan
Chris

 

Welding a plate around the lower ball joint will do precious little, in fact an improperly designed reinforcement actually can create a stress riser that will increase the likelihood of a crack starting. The problem is when you have a big change in bending stiffness - the stress concentration starts right there. And this assumes there are no local weld issues like undercuts at the edge that make it worse. If magnaflux doesn't find any issues, I'd leave it alone.