Like the majority of Land Cruiser owners converting to
power steering, we chose to use the Saginaw model 800 series gear box.
This particular box came from a 1966 Chevy Impala and features four mounting
bolts and 4 turns (actually closer to 4.25) from stop to stop. The Pitman
arm, from a 1974 Pontiac, is approximately 6" inches in length (hole
center to hole center) and nearly flat (i.e., no drop).
With our spring over conversion, this arm prodcues
a drag link that is essentially parallel with the tie rod. This arrangement
results in no noticable bump steer. A 1/4" thick scab plate was welded
to the inner sides of both frame rails. The box is bolted to the
frame with a mounting plate modified from that distributed by BTB Products.
Modifications were required on the front of the mounting bracket to allow
for positioning of the front spring hanger.
The top two of the four steering box bolts pass through
the mounting bracket, scab plate and frame, whereas the bottom two lie
below the frame and are bolted only to the mounting bracket. In order to
reduce stress on the frame, 1/2" I.D. steel pipe was used as spacers between
the walls of the frame. A 3" hole was cut into the frame cross member and
the box was recessed into this hole to the point where the aft fluid fitting
is flush with the front of the cross member. The box was also tilted down
in the front to optimize (i.e., reduce) the angle on the slip-/U-joint.
John
Barron and Ian Archibald recess the box even further into the crossmember,
but this requires cutting more of the cross member and subsequent reinforcing.
The fore-aft geometry of our drag link is not optimal, but does appear
to provide a reasonable compromise relative to conversions that recess
the box further or use a longer Pitman arm.
Although most PS conversions utilize shafts and u-joints manufactured by Spicer (see link above to the Barron and Archibald page), we chose to use what we believe to be a higher quality assembly manufactured by the Borgerson Universal Company. Borgerson has an outstanding reputation in the hot rod and race car community for building extremely strong and safe steering components. Their parts are more expensive, but in our view well worth it. The Borgerson steering components in our Cruiser consist of a 3/4" diameter shaft which mates to the Saginaw box through a slip joint assembly. The slip joint is a zero play, needle bearing joint that allows for up to 15/16" of telescopic movement. It is covered by a heavy duty rubber boot and requires no maintenance.
The
lower steering shaft mates to the FJ40 steering column shaft (which was
cut directly above the connection to the rag-joint of the stock manual
steering box) with an afco-type u-joint. The Borgerson needle-bearing
u-joint is compact in size and is made from billet chrome moly steel, heat
treated for additional strength. It has virtually zero backlash or
radial play, does not require maintenance and should last much longer than
standard non-needle bearing joints. The ultimate breaking torque
of this joint is 679 ft. lbs straight and 587 ft. lbs at a 30o
angle.The u-joint was professionally TIG welded to the two steering shafts.
The stock FJ40 steering shaft is anchored to the firewall with a 4-bolt,
self-centering, greasable flange/bearing purchased by Downey Off Road Manufacturing.
The power steering components described in this page were installed and used for 6 months with the stock 2F engine and a salvage-yard, GM PS pump before starting the Spring Over and VORTEC conversions. We learned early on the importance of carefully adjusting both the steering knuckle stops and the drag link length in order to optimize the performance of the system. The VORTEC engine includes a much improved PS pump and a PS-fluid cooler/radiator that significantly improvs both the performance and longevity of the power steering system. The PS fluid cooler, mounted on the low-pressure (return) line between the gear box and pump, makes a notable difference, and should be considered an important part of such a conversion, especially if running big tires and/or a front locker.
The bottom line, with half-hearted apologies to the OEM
clergy/fanatics, is that power steering is probably the single most
significant upgrade that can be made to a Land Cruiser, especially if it
is going to receive larger tires and driven off road. After 28 years of
driving an FJ40 in demanding off-road terrain, I regret not doing this
sooner!
Cruise
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