Here's the thing about hydro-assist systems: They not only make it possible to steer with one finger no matter how gnarly the terrain, but they take pressure and stress off of the steering box mount, sector shaft, pitman arm, and drag link. As long as your tie rod, steering knuckles, and ball joints are up to the task, a properly-selected hydro-assist setup will not only make wheeling easy and enjoyable, but will extend the longevity of your steering components in the process.
PSC Motorsports understands the ins and outs of setting up a proper hydro-assist steering system. There's more to it than just tapping your power steering box and slapping on an industrial ram. You must consider pump output, fluid volume, steering gear ratios, hydraulic cylinder displacement and force, and a bunch of other stuff to create a hydro-assist system that will work seamlessly on the street while still delivering brutal power off-road. PSC offers complete retrofit systems for most Jeep models including TJ and JK Wranglers, but we threw them a slight curve in that we were working with a '97 TJ with a swapped-in JK front axle. No sweat, because after a brief conversation with PSC's Tom Allen, we had the correct steering gear for our frame, the right pump for our 4.0L engine, and cylinder for our axle. Not to mention all the fittings, lines, brackets, and more that we would need to make the swap go down easily. We brought our parts to All Wrangler Off Road in Wildomar, California where proprietor Jay Miller handled the install in a leisurely afternoon.
We were in a crunch trying to get our install done by press-time, so PSC sent us a few more items than we actually needed just in case we ran into a last minute snag. In addition to the pump, ram, steering gear, reservoir, reservoir mount, and hydraulic lines and fittings, we received PSC's JK axle cylinder assist mounting kit which includes a bolt-on tie rod ram clamp and axle bracket. In fact, if you own a JK, PSC's cylinder assist kits are completely bolt-on.
In addition to the cylinder...
In addition to the cylinder assist components, we ordered PSC's superbly-strong heavy-duty tie rod and drag link kit (PN TR110). The kit includes enough 1.5-inch, 0.250-wall DOM tubing to build your tie rod and drag link as well as the necessary right-and left-hand weld-in tubing bungs to accept the gnarly 1-ton tie rod ends. Miller put a slight bend in the tie rod to clear the front diff cover of the JK axle at full lock. We only used the tie rod because of our custom double-sheer pitman arm and steering knuckle drag link mounts, but the heavy-duty tie rod will easily cope with the stresses of the ram-assist.
The pump PSC included is a...
The pump PSC included is a new CB-series high-volume unit that delivers 50 percent more volume than the factory TJ pump and has a sturdy steel internal thrust plate. The pump came with the correct TJ 4.0L pulley and other than requiring one slightly shorter bracket bolt it bolted right in place of the original unit. PSC also manufactures a direct-fit bolt-on pump kit for JKs utilizing the CB-series pump. The factory JK pumps have an aluminum thrust plate that can get ruined the first time the power steering fluid overheats, so the CB-series pump is a welcome upgrade even on a stock JK steering setup.
Unlike the home-tap jobs using...
Unlike the home-tap jobs using boxes, PSC steering gears use separate fluid circuits for the box and ram and doubles the fluid volume output. PSC recommends a straight 14:1 ratio because it offers more contact on the sector shaft teeth than a variable ratio box with little to none perceived difference in drivability. PSC offers its steering gears in small- and large-piston versions and recommends the small-piston units for street-driven vehicles running cylinder assist such as ours. For the average enthusiast like us, the small piston offers quick and crisp steering feel on the street, while the hydro-assist cylinder delivers plenty of turning power.
Because of our haste in ordering,...
Because of our haste in ordering, we nabbed a JK tie rod cylinder mounting bracket for 13/8-inch tubing. PSC also offers the brackets for 11/4-inch and 11/2-inch tubing. Since we didn't have the correct 11/2-inch bracket for our heavy-duty tie rod material, we used a set of weld-on PSC cylinder brackets instead. Miller measured the maximum stroke of the ram and then marked the center of stroke so the ram could be installed with the cylinder centered and the tires straight ahead. Fine adjustments in ram stroke length can be made via the adjustable ram end fittings.
Miller removed the factory...
Miller removed the factory power steering setup and began the install by bolting the new pump to the block, then the steering gear to the frame (attach the feed and return lines before installing), and finally mounting PSC's very clean reservoir bracket to the power brake booster. The bracket positions the reservoir high enough to clear the ABS components if so equipped. Once the components were installed, Miller measured, cut, and routed the AN hoses from the reservoir to the pump and steering gear.
Miller installed the new tie...
Miller installed the new tie rod, set the toe, and then centered the steering wheel before welding on the new ram mounting brackets. With the ram mounted horizontally on the axle housing, Miller built the high-pressure cylinder-to-box lines and cleanly routed them to the box. We then filled and bled the system before a quick test drive revealed easy one-finger steering with no penalty in steering control. We ran out of time for an off-road test, but we'll be hauling the Jeep to the desert next week and will bring you a quick performance update in the Dispatch section next issue.