Quick-Ra­tio Steer­ing Up­grade For B-Bod­ies

Get­ting Rid of Grandpa’s Steer­ing

Hot Rod - - Front Page - Phillip Thomas

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.

WHAT’S NEEDED

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.

THE GOTCHAS

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.

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