Hi guys,

Did Oldsmobile make boxed lower control arms for Cutlass models?

If so, are they necessary for an anti-sway bar? Thanks.

 

Any 64-72 lower arm was boxed if a rear sway bar was on the car. the boxing includes spacers to keep the arm from getting crushed when you tighten the sway bar mounting bolts.

 

R2R is right.
If a sway bar is to be added, the lower arms must be either boxed withthe available weld-in bottom plates with integrated spacers, or just buy aftermarket boxed arms. The latter might be easier and more cost and time efficient, considering they will have new bushings pressed in and will be prepainted.

AVOID the temptation to use chunks of pipe for spacers without enclosing the bottoms of the arms. I have heard of this being done and the arms will flex, fatigue, and break soon.

Shims may be needed also. Never tighten the sway bar bolts down if there is a gap between the arm and sway bar.

 

Thanks for the info guys. This is helpful should I add one.

So, Olds did offer an anti-sway bar option on Cutlass Supremes back in the early 70's?

 

Yes. The FE2 suspension package was an available option.

 

If you plan an upgrade, I'd plan on a set of aftermarket arms.
By the time you're done messing with 40yr old flimsy arms, they're just as heavy, and not as strong.

 

I don't agree with that. Many of the aftermarket arms I've seen were apparently designed by someone with no concept of structural engineering. First, strength is less important in this application than stiffness (the are NOT the same thing). The large boxed cross section of the factory arms is quite a bit stiffer than that of the round tubular aftermarket arms I've seen. Even worse, there is at least one vendor selling adjustable lower arms with the threaded adjuster right in the middle of the arm. That puts the smallest cross section (the threads on the adjuster) right at the point of maximum bending moment.

DOH!!

Aftermarket arms that are rectangular box sections that are about the same cross section as stock will be equivalent in stiffness, but since you can get repro boxing plates for about $25 a set if you shop around, that seems to be a cost-effective solution to me.

 

I had replaced my 69 arms due to bad rust flaking and pitting. Just didn't see the point in trying to weld plates on the bottom of them because they were so far gone. I guess it all depends upon how good your lower arms are and if you can weld plates in yourself.

I ordered replacement boxed lower control arms from Brothers Automotive. They were great pieces and looked factory original. And... I didn't have to press in new bushings either.

 

I went the same route; my rectangular stock-type arms came from the Muscle Factory. They were made just like the original boxed arms. I got the sway bar shims and bolts there, too - the bolts were cheaper from there than from the local hardware store.

I thought about the $30 plates, but then I would have had to pay a shop to press out and install ($30??) the new bushings ($25), paint the arms (except bottom edges) ($8 for a can of POR15), pay someone to weld the plates in well ($20??), clean the welds, and finish painting.
When I figured the cost, it would have been more than the $100 I paid for the new arms. Calling in the order took less time, too!

It all depends on your skills and abilities - If I could easily weld and press, I would have gone withthe plate method.

All I need now is a stinkin sway bar...

 

Olds started using the rear sway bar on their "muscle car" with the 64-442, still available as 394926. They also had a rear bar for the 66-70 full size cars AKA police cars, 396620.

 

This is exactly what I did with my open control arms, except that I did weld plates across the bottoms. Can't say if they'll work yet because the car is off the road as of now. but I can't see where they won't.

 

Should be fine I think. The plates across the bottom is required to control flexing. Some people use pipe for spacers and do not box the arms. They end up cracking and breaking and they wonder why...

 

Ca you elaborate on this a bit? I have a 70 Olds 98 and my drivers side lower control arm broke on the inner side right next to the ball joint. I always wondered what caused it to break as I didn't really drive the car hard at all. I do remember installing poly sway bar end link bushings on the front sway bar and there may have been an inch of space on the ends before I tightened them up (Just to where they were at when I took them off.

Think that may be why it broke?

 

It could have been a contributing factor.

The above thread deal only with the rear control arms. The front arms were never boxed.
The failure could have stemmed from flawed metal, a previous owner driving it hard, high mileage and rust. One HARD smack over a curb can cause severe fatigue, also.

 

The most likely reason is metal fatigue. This is becoming more of a problem as 1960s cars are still driven regularly. The problem is that the process that formed the control arms and bushing holes had a high probability of initiating a crack or even just a scratch in the metal. As metal is cyclically loaded, these initial flaws propagate, leading to outright failure. It is good practice to have control arms (particularly front control arms) magnaflux inspected when you rebuild the front suspension.

 

Interesting thread.
The previous owner installed a rear sway bar on my 68 cutlass. The control arms are standard "open" type. I'm going to seriously consider an upgrade. Haven't thought much about this till now.
Also, FYI, one hard smack over a curb doesn't cause a fatigue failure. Tens, thousands or billions of smacks could cause fatigue failure, as fatigue failures are caused by repetitive stress cycles. So, the last hard smack could have been the final cycle that caused a fatigue failure.
It's nice to see other Engineers on this board.

 

Being a civil engineer, I drive my oldsmobile over and under what we design!

 

FE2 also includes axle bracing in addition to the boxed control arms and swaybar.

 

I was wondering if they were any good?
http://cgi.ebay.com/ebaymotors/68-72...Q5fAccessories
I see brothers selling the original style ones, year one seems pricey at 139 each for the lowers? I have original boxed arms but they are pitted also have the original sway bar I want to use

 

I have two problems with the upper arms in that ad. First, the use of polyurethane bushings at all locations will lead to binding in the suspension. The geometry of the four link suspension requires the upper arms to twist slightly as the suspension articulates. The stock rubber bushings have enough compliance to absorb this motion. Polyurethane bushings do not. The better upper arms have a metal ball fitting at the front end to accommodate this motion. Second, the round tubing may actually be less stiff than the stock upper arms due to the smaller cross section. One would need to compare the moments of inertia of the two to know for sure.

 

If you already have OEM parts, just clean them up and repaint them. Same with the rear sway bar. I bought a set of rear sway bars that were fairly extensively pitted, but they cleaned up really nice. Couple of coats of sandable primer to fill in some little pits and then some black, they'll look like new. Right now it's too cold to paint and I'm not allowed to do this in the house.

 

I'll try to find the stock replacement ones but at a better price...


I really think the boxed ones are too far gone, I have sand blasted them and painted with POR -15 then GM chasis black but after thinking about some of the comments regarding them being stamped steel well, I think in the scheme of things it would be cheap insurance LOL... I know what ya mean it is dang cold in my garage too! Thanks for the advice gents.

 

If yours are too far gone, just find a good set of open control arms and weld in the box inserts. That's all they did at the factory. Costs a whole lot less than going out and buying a boxed set if you can do it yourself or know someone who can mig it for you. The inserts aren't all that expensive. A new 1" sway bar can be had for cheap. I got mine from Bowtie restorations for around 75 bucks. Fits nice.

 

thanks I might just go that route, but then with the new rubber bushings etc, having them pressed out and in, I can do the welding, have a mig, not a great mig but a mig... it is a good idea I'll weigh the pros and cons, I have the sway bar already it is an original also sand blasted, por 15'd and then painted. I really got to get moving on my project, I need to lower the body back onto the finished frame so I can do the quarter repair/replacement. it is really daunting getting this all back together. I know to eat an elephant one bite at a time LOL.....