1987 Buick Grand National Suspension Walkaround
A Look Underneath the Last Rear-Drive Regal
In the early '80s, an industry-wide switch to front-wheel drive began, fueled perhaps by successful Japanese imports like the Honda Accord that had always been built that way. By the middle of the decade, the Big Three were fully up to speed, cranking out popular front-drive family sedans of their own in the form of the Chrysler K-car, Ford Taurus and GM A-body sedans such as the Buick Century and Chevrolet Celebrity.
Through it all, the Buick Regal on which our 1987 Buick Grand National is based managed to hang on to its rear-drive body-on-frame architecture, possibly because the G-body coupe wasn't as high a priority as the sedans. But 1987 was the end of it, and one year after our Grand National was built, the Regal would become a front-drive "personal luxury" coupe with no hot-rod turbo model, no V8 — and no enthusiast appeal whatsoever.
Much has been written about the history and performance of the Grand National and its turbocharged V6 engine's prowess at the stoplight drags. But what about the bones? What was going on under there that GM was putting out to pasture? We put our 1987 Buick Grand National up on our Rotary lift to have a look.
The double-wishbone front suspension was fully entrenched on the sort of rear-drive ladder frame (yellow) sedans and coupes the Big Three built for decades. How entrenched? Except for the disc brakes, much of what we'll see here — conceptually, at least — applies to the front end of the 1957 Ford wagon that sits in my own garage.
Here we can see upper (green) and lower (yellow) wishbones — A-arms, if you like — that are fashioned from stamped steel. But this is not the sort of high-mount upper wishbone setup we see on many modern cars today, even though the upper A-arm's inner pivot axis does appear to sit high above the frame rail. It's the relative position of the upper ball joint at the outer end of the wishbone that matters, and here the upper A-arm dips down to meet up with a low-positioned upper ball joint.
A large front stabilizer bar sweeps in from the front and attaches to the lower control arm through a drop link that connects through a simple rubber bushing sandwich at its upper and lower ends.
I know what you're thinking: "What is all that gross-looking black crud?"
Why it's a liberal coating of the favored rust-proofing of the day, a tarlike undercoating material that will ruin a white T-shirt if you rub up against it for a second.
The reclined mounting angle of the upper arm indicates that a healthy amount of anti-dive geometry is at work, and from here we can see that the upper arm's inner pivot bushings appear to hover above the frame rail.
Meanwhile, the steering shaft (white) is clearly visible as it passes through on the way to the steering box. That it points directly at the driver's chest is why this is also a telescopic steering shaft. And keep your eyes open for more little zerk fittings (yellow) at the center of each ball joint. This car was designed without the sort of permanently greased ball joints we take for granted today and the seals are fairly ineffective, which is why lube jobs were so necessary back in the day but are largely unnecessary on today's cars.
You have to open the hood and look straight down to see the inner pivot of the upper control arm. The arm itself comes as an assembly that includes the pivot bushings and a cross shaft. The cross shaft in turn bolts to a vertical flange on the frame, with a stack of U-shaped shims (yellow) in between to create a gap. The round object between the two shim stacks is the upper shock absorber mount.
To increase negative camber you'd loosen the bolts and add one shim each to the front and rear to pull the upper arm and its upper ball joint straight in. You'd increase caster by adding one shim at the back or removing one at the front because an unequal change rotates the arm slightly and moves the upper ball joint to the rear.
As you can imagine, a single shim change will affect camber, too, so it takes experience, time and a ready supply of shims of differing thickness to balance both shim stacks and get the alignment exactly where you want it.
The bulge in the center of the lower A-arm is the pocket in which the coil springs rests, with the shock absorber running right up through the middle.
Our steering tie rod sits ahead of the axle, but this is not the rack-and pinion steering we're used to seeing. No, this is recirculating-ball steering, a variation on the worm gear theme with a parade of ball bearings in the works to smooth things out. When you turn the steering wheel, a short "Pitman" arm (white) pivots around the indicated axis. The assist here is hydraulic, but this setup is not long on feel or feedback because of the nature of worm gears.
As the Pitman arm rotates, it moves a central "drag link" (white) left and right. This drag link bridges the gap to the other side of the car, where another short pivoting arm of equal length and placement (not shown) is there to support it. But the second arm isn't connected to the steering wheel and it doesn't create motion; it just goes along for the ride and mimics the Pitman arm's motion in order to keep the drag link squared up as it translates left and right. For this reason the second arm is called the "idler" arm.
Two tie rods connect to the drag link — one for each front tire — and each has a pair of pinch clamps and a turnbuckle (yellow) near its midpoint. Loosen the clamps and twirl the turnbuckle to lengthen or shorten the tie rod to adjust toe-in on each side.
As with all tie rods, the final destination is the steering arm that's cast into the front knuckle, and the tie rod end joint (red) is another of those lube points we have to keep after to replace the grease as it slowly oozes out over time.
Meanwhile, our Buick's brake rotors are dotted with little circular corrosion rings. These are pretty good evidence that our 1987 Buick Grand National's 5,000-mile odometer reading is legit, because the circles are the same diameter as the rivet holes in the brake pads. The number of marks suggests this car has been parked numerous times for long periods after short drives: numerous because there are a lot of them; parked for long periods because of the rust itself; short drives because the rust was never worn away from brake use and we can still see lots of circles.
We can see three of the four pad rivets I'm talking about here. The pad material on the rotor side will have rivet clearance holes of a diameter that matches the marks on the rotor.
These rotors also represent another old-school automotive design practice that has thankfully gone the way of the dodo. These are not mere rotor "hats" that slide over the hub and the wheel studs in seconds once the caliper is off.
Here the rotor is the hub, and you have to pry off that center cap and unbolt the entire hub/rotor assembly from the spindle and disassemble the wheel bearings to remove it. New rotors need to be installed with new wheel bearings and have to be packed with fresh grease. No doubt the practice of turning rotors whenever possible came from the sheer time-consuming and unpleasant nature of this job.
Nowadays the hub is more-or-less permanently greased and the rotor is a relatively inexpensive piece that's a cinch to install, which is why I usually replace brake rotors on my own cars instead of turning them if they look deeply scored or vibrate and shudder.
Our Grand National's front calipers are of the familiar single-piston sliding variety, but the way they're made isn't that familiar at all.
The sliding pins are out there in the breeze waiting to be fouled with either grit or salt (or both) depending on where you live. But the big difference has to do with the fixed part of the caliper frame (yellow), which is cast into the knuckle itself. Today the fixed half of a sliding caliper bolts to the knuckle so it can be more easily installed on the assembly line or serviced by a mechanic.
Just below that, a witness mark on our knuckle tells us that prominent flange (red) on the lower A-arm is a steering stop. The resulting metal-to-metal contact at full lock is sure to make a most memorable popping and scraping noise.
Out back it's very easy to see the characteristic ladder frame curve, as it loops up high to give the solid axle room to move underneath. We can also see a shock absorber, a coil spring, a trailing link (red) and finned drum brakes.
We're seeing the same pieces in this view. But there's only one lower trailing link (red) per side. It takes more than that to locate a live rear axle.
This pair of upper trailing links connects to the center housing of the rear axle and brings the total number of links up to four, the number required to locate the axle in the fore-aft direction and keep it from twisting when subjected to throttle and brake inputs. The sharp angle at which these links are mounted keeps the axle centered and makes it unnecessary to fit a fifth lateral link, commonly referred to as a panhard bar.
To my mind, this setup doesn't seem to offer a lot in the way of suspension travel. Maybe that's why we usually see four parallel trailing links and a lateral panhard bar on the Ram 1500 trucks and some large SUVs, the only vehicle class that still pairs body-on-frame construction and live axles.
Our Grand National has a rear stabilizer bar, but you may have missed it because of the way it is mounted; there are no links, zero bushings. Instead the stabilizer bar bolts directly to the lower trailing links, with the middle section that spans the car hanging in space.
As the body leans in corners, the lower trailing links on each side of the car will cease being parallel to one another, and that motion creates a twist in the bar that generates the roll resistance necessary to prevent the body roll from getting too large or carrying on too quickly.
Simple, but it loads the lower links in a way that forces them to be heavier than they'd be otherwise. And having the trailing links boxed together with the stabilizer bar in one big U shape probably has some noise and vibration downsides. Still, it's a clean-looking way to go on a live axle suspension.
The underside of our 1987 Buck Grand National truly does represent the end of an era that lasted multiple decades. Back in the body-on-frame days it was possible to change the sheet metal at will and the engine when you had something new to offer, without evolving the chassis much at all. Performance had to do with drag-strip launches, and that suited the rear-drive live axle setup just fine.
And so for years it was double A-arm front and some sort of live axle in the rear with either leaf springs or coils. Today the ladder frame is all but gone except for trucks, replaced almost entirely by unibody construction and a wide variety of suspension types and drive layouts. I love the 1987 Buick Grand National for what it was then and what it represents today, but I can't say I'm sorry that the automotive industry has moved on.