It wasn't supposed to happen this way. It was originally gonna be a throwaway vehicle. You know:something you hammer together quickly,have some yucks with, and then sell at a ridiculousloss to the next guy. But then somethinghorrible happened. We started to like The EvilTruck. Damn! We hate it when that happensto a vehicle ya love to hate.
If you tuned in to the last segment of this truck's ongoing and sporadically covered saga, "Over the Road M-715, Parts I and II" (May and June '08, respectively), you'll know why it's suddenly so easy to live with. After installing a Ranger Overdrive, a SM465 transmission, and an Atlas II T-case in place of the clunky stock gearboxes, the truck suddenly became a joy to drive. No matter what the grade or posted speed limit, there was a perfect gear available to keep the engine in its sweet spot. And off-road, it's easy to have either 3.0:1 or 2.19:1 low range for crawling or dune running thanks to the Ranger Overdrive.
So, when it came time to decide which vehicle in the fleet would make the annual trip to the Moab Easter Jeep Safari, it was The Evil Truck that got the nod. However, there were still some big hurdles to jump between the two weeks that marked the decision to bring the M-715 to the '08 event and the scheduled day of departure. As you'll read about this month, one of those hurdles was the horrendously inadequate manual steering setup. Trying to manhandle the 38s on the street was bad enough, but it would've been next to impossible trying to turn on tight slickrock trails with the tires at 10 psi. The second, which you'll read about next time, is the torturous stock seating and the complete lack of any protection in the event of a rollover. So, check out how PSC Motorsports made it easy to ditch the factory manual steering for an infinitely better power assist setup. And check back next month to see the truck transformed with better seating and safety for up to eight passengers.
We've used components and...
We've used components and systems from several different companies in the past, but can honestly say PSC Motorsports is fully on its game. Only a few days after speaking with Tom Allen at PSC, two boxes arrived with everything we needed to convert the '68 M-715 to power steering. And no matter what sort of rig you have, PSC Motorsports offers just about any steering-related component you could want to upgrade or replace worn or inadequate parts.
PSC sent us one of its N-series...
PSC sent us one of its N-series high volume pumps (PN SP-1500BX) mounted on one of its trick small-block Chevy brackets. The pump is similar to an LP-style pump with an attached reservoir, but the N-series pump has a cast body for use with an external reservoir. The bracket can be mounted either up high on the cylinder head or down low on the block. PSC also installed its 6-inchdiameter V-drive pulley on the pump. Serpentine pulleys and other brackets are available.
The steering box PSC sent...
The steering box PSC sent us was an '80-up metric O-ring type with a 13/16-inch, 36-spline input shaft and a big bore piston for rugged use. Although we currently have no plans to add a hydraulic ram assist to the steering, our box came tapped for the lines and our high output pump can handle the added volume. If we ever do find a need for hydo-assist, it'll be as simple as uncapping the ports and hooking up our ram lines.
We started by removing our...
We started by removing our stock pitman arm, then unbolting the rag joint from the steering shaft and removing the factory box.
We bolted the PSC Saginaw...
We bolted the PSC Saginaw box straight to the factory frame mount. We weren't able to utilize the PSC box's fourth bolt hole since the factory Jeep mount is a three-bolt type, but it's no biggie. We were bummed to find out the M-truck pitman arm bore was too big to work with the Saginaw box's sector shaft, which you can read about in the sidebar.
PSC included the correct 13/16-inch,...
PSC included the correct 13/16-inch, 36-spline by 3/4-inch round Woodward u-joint to connect the steering box to our factory shaft. We first mocked up the shaft to determine where to cut, making sure we erred on the long side. It's easier to cut twice than try to find a replacement shaft the night before departure.
After removing the shaft,...
After removing the shaft, it took a little ride in the chop saw to cut it to the right length. After making the cut, the shaft was reinstalled and test-fit one last time before it was removed for final welding.
If you're a bad or inexperienced...
If you're a bad or inexperienced welder, it's probably not a good idea to go welding your steering components. And even if you're a great welder, the shaft should be drilled and pinned as an added safety measure to ensure the shaft won't come apart in the event the weld cracks and fails. We wrapped the u-joint in a wet cloth diaper to keep the grease seals from melting from the heat of welding.
With the box mounted and the...
With the box mounted and the steering shaft connected, it was time to find a place to mount the PSC 6-inch Competition Reservoir (PN SR-150K). The reservoir employs internal baffles and doesn't use a filter. PSC has noted that for its competition and high-rpm applications, there may be some aeration in the fluid caused by the reservoir mounted filters. We bolted the reservoir straight to the body next to the radiator using the reservoir's integral threaded mounting holes. If a vertical mount is required, PSC includes a trick aluminum clamshell bracket.
With the pump, box, and reservoir...
With the pump, box, and reservoir mounted, it was time to build the lines. The return lines are under low pressure, so PSC uses these trick socketless fittings and hoses that are a real time-saver. Simply measure to length and then cut the hose with a utility knife. After lubing the barbed fitting with clean power steering fluid, you press them to gether and it's done. It's really that easy.
We've worked with our fair...
We've worked with our fair share of braided steel line and will never go back to it. The bloody fingers and frustration make it just not worth it. So we were glad that on the high-pressure side, PSC specs out top-quality Eaton reusable fittings rated to 2,500 psi, and Ryco high-pressure hose. After measuring, the hose is cut to length with a cutting disc in an angle grinder.
Next, the shell is threaded...
Next, the shell is threaded onto the hose and the fitting is installed. With regular braided steel it's always a hassle, so we feared the worst. However, we were pleasantly surprised at the ease with which the Eaton fittings went together.
Here's our finished underhood...
Here's our finished underhood installation. The N-series pump came with AN-6 and -10 fittings already installed and PSC included the correct metric O-ring to AN-6 adapters for the steering box. After sourcing the correct belt from our local NAPA, we filled the reservoir and then bled the system. The power steering works flawlessly and completely transformed the character of the truck, both on- and off-road. But we'll go into that a little more next time.
We didn't actually start this conversion until the day before leaving for Moab. While every single part PSC sent worked and fit flawlessly, we neglected to obtain the correct pitman arm even though we suspected our '68 manual steering box had a larger sector shaft than the Saginaw boxes. We had the stock pitman arm from an '85 Dodge Ramcharger in the shed that matched the Saginaw sector shaft and matched the M-715's 1-ton GM-sized drag link tie rod. The Ramcharger part worked, but its shorter length severely limited the truck's turning radius. Once in Moab, we found an Omix-ADA pitman arm for an '80s CJ at Moab 4x4 Outpost. We had Moab 4x4 Outpost retaper the CJ pitman arm for the GM 1-ton-size tie rod and it worked like a charm.