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Aug 29, 2023

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General Motors built the last of its full-size, body-on-frame, rear-drive passenger cars at its Arlington, Texas, plant in 1996, some 27 years ago, but interest in these long-discontinued vehicles endures. Used by families, retirees, law enforcement agencies, and taxi fleets, the final version of General Motors' B-body ran its course from 1991 to 1996, with over 200,000 produced under the Buick Roadmaster banner. (Chevy had the Caprice and Impala SS while Oldsmobile had the Vista Cruiser wagon and Cadillac had the Fleetwood D-body, a lengthened B-body with a 6-inch-longer wheelbase.) Most of the GM B-bodies had no high-performance inclination until Chevy got the great idea of dropping the C4 Corvette's LT1 V-8 into the Caprice to create the 9C1 special service police package for 1994, which would dominate the law enforcement market for several years.

That move caught the eye of Chevy performance head Jon Moss, who quickly co-opted the plan to turn the police package 9C1 Caprice into a cash-crop performance model—a reboot of the classic Impala SS. Using the Corvette V-8, but detuned for the heavier B-body with a torquier cam and iron heads instead of aluminum heads, the Impala SS also sported more aggressive springs and shocks, a grippier wheel-and-tire combo, and a quick-ratio 12.7:1 steering box. To the benefit of all B-body buyers (Oldsmobile bowed out of the B-body in 1993), the Corvette LT1 small-block found its way as standard equipment into the Buick Roadmaster and Cadillac Fleetwood Brougham between 1994 and 1996, and became an option on Chevy Caprice those same years. Unfortunately for the Buick Roadmaster, Cadillac Fleetwood, and LT1-optioned (non-9C1) Caprice, the standard 16:1 steering box was the only option.

Though the LT1-powered B-body has explosive torque off the line and usually catches ordinary cars napping at the light, the steering leaves something to be desired. Jockeying to get into and out of parking spaces involves a lot of unnecessary turns of the steering wheel, and road response can feel a bit numb. And with 4.25 turns lock-to-lock for the stock 16:1 steering box, we can understand why. A change to a quick-ratio gearbox is the simple answer, and is a much lower-cost option than the headache of converting to a rack-and-pinion setup. Compared with stock, a quick-ratio box is only 2.75 turns lock-to-lock—problem solved! Borgeson Universal has offered a quick-ratio steering box upgrade for decades and when we finally decided to do something about the numb feel of the steering on our captive 1994 Buick Roadmaster, we gave them a call. Borgeson responded with its popular 12.7:1 quick-ratio box, part No. 800130, which has a suggested retail price of $519.75. (Borgeson says that the price is typically about 10 percent less at larger big-box mail-order retailers like Summit Racing.)

Chevy did incorporate a quick-ratio 12.7:1 steering box on the 1994-to-1996 Impala SS (the same one that also can be found in the 9C1 special-service Caprice and taxi fleet versions), so you'd think it would be simple to use one of these original units, but this factory version of the quick-ratio box featured a specific pitman arm shaft that has only three keyways, not four. Since the standard B-body steering box has a pitman arm shaft with four keyways (at 3, 6, 9, and 12 o'clock) the pitman arm you'll need should also have four keyways. Since the quick-ratio version of the B-body pitman arm with three keyways is not a serviceable part and is no longer available, you'll need to reuse your four-keyway pitman arm when replacing your 16:1 box with a Borgeson 12.7:1 box.

Before digging into the installation, we want to note that Borgeson's quick-ratio 800130 steering box has applications across a wide range of GM models going back to the early 1960s. And while you could argue there's nothing terribly wrong with the 16:1 box on our 1994 Buick Roadmaster (it worked fine), there are many other performance models that can benefit to a much greater degree, including all full-sized GM models from Buick, Oldsmobile, Pontiac, Chevrolet, and Cadillac going back to 1965, all the classic midsize A-body intermediate muscle cars (Chevelle, LeMans/GTO, Skylark, Cutlass) from 1964 to 1977, F-body ponycars like the 1967-to-1992 Camaro and Firebird, X-body models like the Chevy Nova, and the downsized intermediate G-body range from 1978 to 1988 (Malibu, Monte Carlo, Regal, Cutlass, LeMans). One part number from Borgeson fits them all. Over the years, GM kept the overall shape, interface, and mounting points of its Saginaw-style steering boxes the same across many car and truck lines in a move to keep the cost down, even when the steering box design was periodically updated. This means the late-model Saginaw 800-series box that Borgeson uses as a core fits a huge selection of GM cars, requiring only a change to the rag joint (if needed) and/or the fluid couplings (early-style boxes will use a compression inverted-flare fluid fitting with a brass insert instead of an O-ring).

The general instructions for removing and replacing a steering box are straightforward. (We'll have specifics regarding the Buick Roadmaster momentarily.) First, the power steering feed and return lines are removed and the fluid is drained. This is followed by the removal of the pitman arm using a puller tool. (These can often be borrowed from your local parts store.) The steering flange is removed from the steering input shaft and the three (or four) bolts holding the box to the frame can be removed and the old box taken out.

If your vehicle requires a new rag joint (our Buick didn't) now's the time to install one. (Borgeson offers part No. 990012, for $80.87, which has the ¾-inch, 30-spline coupling you'll need.) This will be used to establish and set the center point of the steering box's arc before bolting the box to the frame with either the three or four original steering box frame bolts. The rag joint can then be attached to the steering shaft and the pitman arm can be reattached. Depending on the age of your car, you'll either thread the fluid couplings onto the new box (for late-model applications like the Buick Roadmaster) or insert the brass inverted-flare fittings (included) into the box before screwing the fluid lines tight. If your older car needs new power steering fluid lines, Borgeson offers a kit (part No. 925103, $72.61) to replace old, frayed lines—these are compatible with the late-style o-ring seals in the Borgeson box.

To help us get the job done quickly, we reached out to Eric Bishop of Bishop's Custom Cars in Palm Desert, California (442-666-8621). Make no mistake about it, Eric is a highly experienced fabricator and custom-car builder, and having a guy like him swap out a simple steering box is like asking a three-star Michelin chef to whip up a cheeseburger—it's probably overkill, but we were on a tight time-crunch, and we like hanging out with Eric just for the fun of it. That said, this is an easy swap, and aside from some very tight physical constraints like interference from the clunky ABS control unit and its vast bracket, it can be done at home on jackstands.

The first of many cursing sessions you'll experience with a late-model GM B-body steering box swap is dedicated to the ABS system. The first generation of GM anti-lock brake systems (a Bosch-sourced unit) had an imposing control unit that took up considerable underhood real estate. Located beneath the air silencer box, the ABS unit takes up most of the elbow room you'd typically need for tools and a clear line of sight to the area you want to access. To help stabilize the unit, GM designed a bracket that attached the ABS control unit to the steering box below it. We had a choice of either putting a tool on the 13mm nut to take it off or taking a picture of the offending bracket, but not both at the same time. Since there's no corresponding attachment point on the Borgeson box, this nut thankfully won't need to be put back on.

As seen from the driver-side fenderwell looking toward the rear of the car, the original steering box on the Buick Roadmaster has three 16mm bolts that attach the box to the frame from the outside. The top one is the longest and needs to be put back in the same position when swapping the stock box for the Borgeson box.

We thought we might be able to squeeze the old steering box out through the space that was available, but in the end we were forced to disconnect the front anti-sway bar bushing from the front K-member to clear the girth of both boxes.

One of the big visual differences between the Borgeson quick-ratio box and the factory box is the number of mounting tabs—three for the stock box and four for the 800-series Borgeson box. Most applications will not need the extra, fourth hole (pointing finger) and in some cases the tab will need to be cut off if it interferes with the chassis. This is the case with third-generation F-bodies (1982-to-1992 Camaro and Firebird) and will need to be cut off for these applications, but not today for our Buick Roadmaster!

A late-model GM B-body has a protective sleeve along its steering shaft that protects it from dust, heat, and chemical spills, but it's also quite an obstruction to work around in the tight confines of the Buick's engine compartment. The sleeve attaches to the top of the steering box and allows the shaft to rotate freely, but it must be detached and slid partway up the shaft for a steering box swap. As seen from below, looking toward the driver-side framerail, the cover is slid up the steering shaft from the rag joint so that the joint can be coaxed onto the steering box input shaft splines with help from a prybar.

Take a close look at the factory steering box output splines that engage the pitman arm. This is one of the four keyways that index the pitman arm to the steering box (yellow arrow)—they force the pitman arm into the proper alignment, but each keyway is three teeth wide, not one tooth wide like the Borgeson 800-series box. Normally, you'd try to find a pitman arm with four single-tooth keyways (short story—there aren't any), but it's easier to grind away two teeth adjacent to each keyway on the output shaft and use the original pitman arm.

Grinding down the output splines on the new Borgeson box is probably better done with the box removed from the car, but Eric had already invested significant time installing the box so it happened with the Buick on the rack. You can grind down the two splines adjacent to each keyway, or one each on either side of each keyway, but make sure you do it the same way for each keyway. We ground one on each side of the single-spline keyway but suspect doing two adjacent ones would be better since our solution resulted in the steering wheel angle being off by 45 degrees. This was quickly corrected with a string and some readjustment to the tie-rod end length on each side.

The best part about grinding the four keyways wider is that the pitman arm now fits the output shaft! By way of some explanation, the reason you can't use a pitman arm from the vehicle the Saginaw 800-series box was originally designed for is that such pitman arms had a ball joint on the small end rather than a tapered hole to receive a ball joint. Using a pitman arm from a late-model Impala SS or special-service taxi variant (the quick-ratio version) is a non-starter because it has three keyways and will not match the output splines of the series 800 box.

Reattach the castellated nut that connects the pitman arm to the drag link, snug up the three 16mm bolts holding the box to the frame, tighten the collar bolt holding the rag joint to the box's input shaft, reconnect the 18mm power steering fluid feed and return fittings, and reattach the steering shaft dust sleeve to the steering box. Of all these operations, reattaching the line fittings to the steering box will be the most difficult operation. You'll be trying to align and thread them blind, as there's no easy way to see them or get a tool on them. The best way to get them started is to pull the line up flush with the inside of the fitting so that only the fitting threads touch the steering box threads; otherwise, the hard line will cock the aluminum fittings sideways, keeping them from threading in.

The last item on the steering box swap checklist is to fill the system with power steering fluid. Eric suggests that you begin with the car off the floor and with the engine not running. As you fill the system with fluid, periodically turn the steering wheel left and right to work any air bubbles out of the system. Once it looks full, start the engine and repeat to get the remaining air bubbles out. Observe the "cold fill" line on the reservoir cap; otherwise, as the fluid warms up, it will expand and leak out at the cap. One last thing you'll want to do before sparring for that front spot at the shopping mall is to get a proper alignment!

David Freiburger and Mike Finnegan thought this was the best episode of Roadkill at the time, and it's easy to see why. Episode 23 has it all: a Mad Max-vibe 1968 Dodge Charger built with motorhome parts, sideways Dukes-style action, lots of low-buck wrenching, hilarious snafus, and cameo appearances by the Macho Grande from episode 8, the 66 Buick Special convertible from a pre-Roadkill episode, the ramp truck from episode 20, and the Fury from episode 22. Want to see more? Sign up to MotorTrend+ today and start watching every episode of Roadkill, plus much more!

Borgeson's Quick-Ratio Box Is Only 2.75 Turns Lock-to-Lock Why Not Use an Impala SS Steering Box? A Quick-Ratio Box With Many Applications How To Install a Quick-Ratio Steering Box Extra Parts You May Need Installation Details for LT1-Powered B-bodies ABS Bracket Nut Steering Box Bolts Front An ti-Sway Bar Bushing Steering Box Attachment Points B- Body Rag Joint Attachment Pitman Arm Output Splines Grinding Down the Output Splines Pitman Arm The Last Part Is the Hardest Part Topping -Off the Fluid