Car: 85 Oldsmobile delta 88 royale brougham coupe

Looking to buy new sway bar bushings but need to know dia? Lots of different sizes listed.

 

Sway bar diameter depends on what options the vehicle came with. If you don't have a caliper, the easiest way I've found was to use an adjustable wrench and gradually open until it just fits the OD of the bar. Measure the wrench opening and you should be very close. The sway bars are metric, so you may need to convert your measurement to an equivalent SAE size to get the right part#.

Why not get a bigger front and add a rear? It's cheap and easy. If you are buying bushings, replace the end links, too. In the salvage yards, there are so many full-size gm cars (1977-96!), that you should be able to find a front and rear set to bolt-in. Find the biggest ones you can. I upgraded the front from 25 to 30mm and added a rear. For the rear, there is a mounting bracket that slips inside the lower rear control arms that you need. A sway bar upgrade was one of the first mods I made to the car and it definitely improved handling and stability. I spent less than $100.

 

Or, you could just use an inch ruler to measure the adjustable wrench opening...

 

Im going to just keep the susp setup stock, I will be replacing the end links a the same time.

Unfortunately I dont have access to measure myself so was hoping someone would know the measurement.

 

I would ditch the stock bars and upgrade.

The stock bars are hollow and allows them to rust. I forget what year and car (I want to say 78 F Body, but that doesn't sound right) has a solid bar thus making it stronger

 

While I appreciate that people want to improve their vehicles, the O.P. didn't ask about upgrades, he just want new bushings for his stock swap bar.

As for hollow vs solid bars, this is a very common misconception. An anti-sway bar is a torsion bar, and the closer you get to the center of a rod in torsion, the less effective that material is in maintaining stiffness. The effectiveness of the metal in increasing torsional stiffness (and thus bar stiffness) goes with radius squared. A hollow bar with the same torsional stiffness as a solid one will have a fraction of the weight. Solid bars may be stronger, but that doesn't help handling. Stiffer is what is important, and stiff with less weight is better.

 

I was just offering a suggestion. If the bars he currently has are hollow, I think getting solid bars are better.

The thing that does really suck about these cars is that they use so many different parts for the same things. My old Delta, built Nov 1984, had 194 bulbs in the dash, but this one, built Oct 1984, has 168 bulbs, and the bulbs listed are 3 different sizes. It's lke that with a lot of parts and bolts

 

Only if your idea of "better" is "unnecessary weight hanging off the front of the car." Sorry, but this is mechanical engineering 101. A tubular bar will have the same stiffness for less weight. Automakers (and aftermarket suppliers) have used solid bars because they are cheaper to make - you don't need to worry about kinking the tube when you bend it. That only makes them "better" for the manufacturer from a profitability standpoint.

 

I had no idea the stock bars were hollow for that year and model... The ones on that year Cutlass were solid. Interesting. Most likely to lessen the weight of those bigger cars.
Parts are available at Rockauto for sizes 1" to 1 5/16"!

Do the adjustable wrench trick (if you have a big enough one) or caliper (preferred way).