Quick-Ratio Steering Upgrade For B-Bodies
Getting Rid of Grandpa’s Steering
Sometimes, upgrades happen on the machine’s time. Such was the case when it came time to replace the seized power-steering pump on HOT ROD’s project 1996 Buick Roadmaster. The luxury version of the venerable GM B-body wagon included the RPO VM7 variable-assist power-steering system that used a solenoid-actuated needle valve to regulate steering effort depending on speed, offering high boost for slow-speed driving while increasing steering effort at higher speeds for more stability. While modern cars still do this, it’s largely a gimmick for most drivers. Worse yet, the VM7- specific power-steering pump, solenoid, and lines are nearly nonexistent nowadays, which would make any road-side repair more difficult for this highway warship. Thankfully, GM likes to build its cars like LEGO kits, and we decided to move to a conventional powersteering pump and quick-ratio steering box from the 9C1 and SS. Not only would this give us parts that could be found in any small town, but it also reduced lock-to-lock steering by a full turn, from 3.5 to 2.5 turns. This is a great upgrade for anyone who has a Buick Roadmaster or Cadillac Fleetwood with the VM7 variable-assist.
Due to the solenoid in the
VM7 pump, the outlet is in a different position (side) than the standard pumps (rear). This means that the hard lines are not interchangeable. To convert over to the standard pump, the pressure-side line must be replaced with the appropriate part. We ordered AC Delco PN 36367690 from RockAuto, along with a new AC Delco PN 3630940 for a new return line. For the pump, we picked up AC Delco’s PN 36P0272 remanufactured pump along with ATSCO’s SS/9C1 remanufactured steering box PN 6566 (AC Delco’s remanufactured PN 36G0134 was not available in this story’s time frame). You’ll also need to track down flanged M10x25mm bolts, as in our pump, the blind threads for the mounting bosses were not deep enough for the bolts from the VM7 pump
(one bolt still had to be trimmed approximately 1 mm). Of course, unless you plan on buying a new pulley, a powersteering pulley puller is needed. These are available for rent at every major parts store, and Harbor Freight has an affordable kit for this once-in-a-blue-moon job. You’ll also need a 10mm, 13mm, 14mm, and 15mm socket and wrench set, a 15/16-inch deep socket for the pitman arm, a pitman arm puller, a 6-inch extension, a 5/8-inch line wrench, angled needle-nose pliers, a drain bucket, and possibly a cheater bar, torch, or penetrating lubricant.
This job should be pretty straightforward, but the LT1 accessory drive, especially with the optional tow package’s cooling fan on our Roadmaster wagon, is a little cramped. This is also the era of mixed standard and metric fasteners. Once the fan shroud is out of the way, you can remove the two holding nuts for the coolant pipe and slip it out of the upper coolant hose. With that aside, it’s possible to extract the main serpentine belt before removing the pulley to access the mounting bolts. For the hard lines, pulling the alternator gives you access to the high-pressure hard line and the low-pressure return line. Additionally, when removing the steering box, we found it easiest to access the box’s fittings and mounting bolts with the front-passenger wheel off—and don’t forget there’s a nut between the lower ABS pump bracket and steering box (near the preload nut on top) to remove.
01] The stock bolts from the VM7 variable-assist pump are too long for our standard pump. You can grind them down, but we elected to grab new bolts from the hardware store for a whopping $1.20.02] On the right, the flanged M10x25mm bolt is a near-identical replacement.03] Maybe the hole wasn’t fully threaded, or maybe they’re all this way—either way, we had to trim one of our M10x25mm bolts just a hair.04] Problem solved. 01 02 03 04
05] A glove finger is great for covering the fresh O-ring and fitting as the hard lines pass through our high-mileage engine bay. This pump had been leaking for some time, but the previous owner ignored it.06] This also keeps the O-ring in place, preventing it from falling into the abyss.07] The VM7 variable-assist power steering uses a pressure sensor to determine—something. With the system being eliminated, this pressure sender was no longer needed and we installed the provided plug and O-ring.08] It’s necessary to remove the A/C compressor wire to slide in the new hard line.