MDchanic

Hello, all. I'm putting this question up now, even though I won't be able to do the work until spring, because I figure it may take a while to get an answer.

I've got a '73 Delta convertible and I've got the rear sway bar (and all mounting parts) from a '73 Grand Ville.

I've put the car up on ramps (so the suspension would remain loaded) and lined up the bar and mounts, and everything looks like it should fit perfectly.

Now for the problem: The lower control arms are not dimpled to make it easy to drill the necessary mounting holes for these suckers.
I may not be remembering correctly, but I believe that the A-bodies had some dimples, because I did install a sway bar on an A-body with a pair of non-boxed control arms once.

The way that these things mount is interesting:

There are two roughly ⅛" stamped U-shaped (actually square-section) brackets, one for each side, which fit perfectly inside the two control arms, creating a sort of "boxed" arrangement in the area where they're mounted. The control arm forms a sort of right-angled, upside-down U, the bracket forms a right-angled, upside-right U, and the two of them together form a box.

Each bracket has two threaded holes in each "upright," which accept ⅜" (I believe, but I didn't measure) bolts, four bolts per bracket, eight bolts total.
The bolts pass through holes in the control arms to hold the brackets in place.

Finally, there are two large bolts on each side that go through the flattened end tab of the sway bar and into the bottom of the bracket.

My question is, does anybody have any sort of shortcut to getting these holes in the right places the first time?
Templates, tips from experience, pages from the assembly manual with dimensions (I'm not even sure how big the holes were supposed to be), measurements from actual cars would all be welcome.

I can measure it up as best I can and get it "close enough" if I need to, but I figured I should ask whether anyone had an "easy way" before I start grumbling and throwing wrenches.

Thanks!

- Eric

(I've attached a few photos to show how this thing goes together.
The car is on a jack because I hadn't figured out that with a jack in the way, you can't get the bar into position [Doh!].)

2blu442

Eric, the 1973-77 Cutlass used the same mounting style. I understand the 77 Delta used the same bar as the 73-77 Cutlass.

If you could get pictures/measurements from that vintage of Cutlass then mount yours to the same location on your control arms I think that would work. John

Tony72Cutlass'S'

Eric,

Just a thought, i'm on my cell now so i can't check, but maybe Kurt has the 73' Assembly manual loaded up onto Wildaboutcars?

2blu442

I can't lay my hands on a 1973 Chassis Service Manual, but I checked a 1974. It shows a diagram but no measurements. John

MDchanic

For those who may need this information in the future, I have the answer to my own question.

If you get a used rear sway bar out of a '71-'75 A-body, as I did, prepare for the possibility that one or more of the bolts that hold the sway bar to the brackets will be rotted inside the bore in the sway bar where it passes through, and will break off when you try to remove it.
In my case, it left a roughly ⅜" stub which was easy to grab with ViseGrips, and a bit of heat from an oxy-acetylene torch freed it right up.

That being said, the sway bar brackets can be attached to the lower control arms without removing the arms from the car, so long as you remove the wheels and disconnect the shock absorbers at the bottom.

In my case, I made a template out of aluminum roof flashing to locate the holes, and even then, I was not able to get them perfectly right (though I was much closer on the second bracket than I was on the first).
Initially, I had intended to make the template by tracing the features of the brackets, but I had the bright idea to actually measure it, and made the pleasant discovery that (duh) this American car, designed in the 1960s, without the aid of computers or the interference of the metric system, was laid out to normal, sensible dimensions.
Specifically, if you look at a bracket from the side, with the bottom facing down toward the ground, as it would be when installed, you will see two threaded holes close to the upper edge, one hole close to the left edge, and the other not-so-close to the right edge.
The holes are located from the right upper corner.
From that point, the centers of both holes are ½" below the top edge.
Measuring from the right edge, the center of the first hole is 2⅛" from the right edge, and the center of the second hole is 7⅛" from the right edge.
These dimensions are the same for both sides of each bracket (if you rotate the bracket in your hand, you have the same configuration in front of you again).
If you trace the outline of the bracket, then lay out the centers of the two holes as above, you can punch the two centers and then drill them with a very small drill bit, so as to just be able to centerpunch through the holes onto the control arms. I cut the template 3/32" shorter than the bracket by cutting off the bottom edge 3/32" higher than would have been indicated to allow for the 3/32" thickness of the control arm where it flares out at the bottom (which prevents you from lining a template up with the bottom of the arm), so the the template could be rested in the "gutter" along the bottom edge of the control arm.

Once I had a template, I removed the wheels and the bottom shock mounts, and placed the template in the "gutter" against the sides of the control arms, with the forward-facing edge exactly 12" from the bottom corner of the control arm and centerpunched both holes (do them both at the same time, one shot each, without moving the template - if they need to be deeper, you can hit them again after the template has been removed).

I drilled the holes first with a small bit, about ⅛", and then with a bit the size of the bolts. It seems as though a small amount of misalignment is inevitable, especially between the two opposite sides of an arm (I think the points I measured the 12" from were not really matched to each other), but the misalignement was small enough to be cured by "wallowing" the holes sideways with the drill bit.

Here are some photos, which I hope make it a bit easier to see what I"m talking about. The pink paint was there to mark the locations where the brackets fit with the sway bar attached, so that I could be sure I was in the right neighborhood.









For whatever it's worth, the job was easy with the car on a lift, but would not be too bad on the ground either.

I do not have the sway bar with me where I am right now to install it and prove that all fits well, but I will add a final post in a few days when I do hook it up.

- Eric

joe_padavano

Now that's what I like - an O.P. who answer's his own question.

MDchanic

I hate when threads "drop dead" without any resolution.

I've got a "diagnose that noise" quiz thread coming up (when I get around to writing it) that has its resolution already included .

- Eric

copper128

Eric, sorry I never saw this thread earlier. I had this same dilemma using the same style bolt in insert in the original undrilled lower control arms on my Delmont. When installing a 71-76 B & C-body bar, I just bolted the sway bar to the inserts then held the assembly in place and marked the locations of the inserts. Then I took it back down and unbolted the bar, clamped the inserts in place in the LCA's and mig-welded them along the sides. Bolted the bar back on and all done. Been that way for several years now with no issues.

MDchanic

Well, of course, there's no arguing with a MIG welder .

- Eric

MDchanic

And, finally:







The bar fit well, does not seem to affect ride height (I have had them pull one side of the car down a bit when not properly aligned), and does tighten it up a bit.

We'll see how it feels over the next hundred miles or so...

- Eric

Tony72Cutlass'S'

Bar Looks good, i can imagine they're hard to come by for a B-body.

By the way, i thought you said your car was rusty, i dont see any rust on the frame or floor. Or did you just POR Everything?

brown7373

Glad you got it on okay. I put one on my 70 Bonneville Convertible last year so I understand how you have to play with it to get it on. I mounted the bar to the brackets, then found the spot the brackets would slip into the control arms, since the control arms (on mine and I guess others) are at a slight outward angle. I marked the front and rear edges of the brackets, made a template of the holes and drilled.

It was a lot more difficult that installing one on my 72 Cutlass, which was pre-drilled for the bar. It was just shim between the 2 sides of the open arms and bolt it on.

MDchanic

The PO painted the entire bottom with cheap black spray paint to cover up the rust and Bondo.
Believe me, it's rusty

Now that I've had a chance to drive it a bit, I can say that I like it with the rear bar.
As with other cars, the rear bar tightens it up, removes some of the "floating" feeling, and keeps the rear glued down much better. It handles like a much smaller car now, and doesn't feel rough or uncomfortable.

- Eric