When we had our Blazer's steering crossed up (driver side
droop, passenger side stuff) with the factory steering setup and couldn't
turn left, it was evident that it wasn't going to make the grade off-road,
we knew we needed to install cross over steering to correct the problem
but we didn't quite know why cross over worked so well. We called Stephen
Watson of OffRoad Design and asked him to explain the geometry of cross
over steering and why it works so well, his thoughts on the subject follow
in the "Cross over explained" section.
Cross over explained
Steering problems are very
common on a lifted 4x4, and unfortunately for us, the GM straight axle
steering is the worst of them all for problems associated with a lift. The general term:
“steering problems” basically amounts to one of 4 specific problems.
1: It breaks.
Crossover (or any other kind of steering) doesn’t do much if
you’re steering box isn’t attached to the frame, or if the linkage is
broken. But the parts in the kit are beefy enough it should never break.
A box brace is always a good idea also.
2: It lacks power.
Crossover doesn’t do much for actual steering power, you’ll
have to go to hydraulic assist or other steering upgrades for that one.
It may help just having the proper geometry from the crossover, but
that’s not the main purpose of crossover.
3: This is the good stuff:
Bumpsteer, Bumpsteer is
defined as unintentional steering motion of the front tires when the
suspension moves in a straight up and down motion, for example hitting a
speed bump or large dip in the highway.
This causes both front tires to move upward the same amount.
You can feel bumpsteer in your truck by letting go of the steering
wheel when you’re driving over speed bumps or “whoops” in the
highway. If the wheel jerks
as you go over the bumps, you have some degree of bumpsteer.
GM steering can work well in preventing bumpsteer just because the
steering linkage is pretty well located for vertical travel and moves in
the correct arc to keep the steering wheel and the tires in sync.
Crossover steering will have some bumpsteer because the leaf
spring suspension moves straight up and down while the crossover draglink
moves side to side. Since the
draglink end at the axle will move in an arc, it will have some small
component of side to side motion as it travels vertically and this side to
side motion causes bumpsteer. However,
this is generally an acceptable level of bumpsteer for most drivers.
4: This is the really good
stuff: Roll steer. Roll steer
is defined as unintentional steering motion of the front tires when front
axle “articulates” compared to the frame, meaning one side moves up
while the other goes down. Roll
steer conditions are possible in two driving circumstances: cornering,
where the whole body rolls compared to the frame, and off-road driving
where only the front axle moves compared the frame.
Roll steer is usually just annoying when driving on the street,
it’s hard to get enough body roll to cause serious problems.
The off-road articulation situation is the one that concerns us.
steering action pops up in 2 ways;
is when the axle housing itself under steers when articulated due to the
arch in the spring. This
motion is one we just have to live with because it’s due to the motion
of a leaf spring suspension itself. As
one side of the suspension compresses and the other extends, the leaf will
make the axle move forward on the extension side, and backward on the
compression side. This motion
will steer the axle housing under the vehicle.
Make sure you understand how this works before you continue
reading, it’s important to understand that the axle housing steers under
the truck when it articulates.
other way the axle can steer is when the steering linkage moves in a
different arc than the axle. This
is found in poorly designed link type suspensions, and is also found in
the factory GM front suspension. This
is where crossover steering comes in to play.
Imagine the standard GM steering on your truck, with the suspension
twisted in such a way that the left (driver’s side) tire is drooping
away and the right side is compressed.
The left side of the front axle will be moved forward because of
the increased arch in it’s spring, and the axle will be at an angle
under the truck because right side is moved back due to the spring being
close to flat on that side. Now try to turn left. Your
steering box turns the pitman arm so that the end of the arm moves to the
front of the truck. But the
end of the draglink where it ties to the axle is already closer to the
front of the truck than it’s supposed to be so your pitman arm’s
motion doesn’t actually turn the tires to the left, it just makes them
turning the box till you’re against the stop and you’ll find that you
can only get the tires to point straight, it won’t move them to left
because the steering box is maxed out and doesn’t have any rotation left
to pull the draglink forward.
Now imagine the same scenario with crossover
steering. Since the draglink
in a crossover setup moves side to side, the angle of the axle under the
truck doesn’t make an appreciable difference in how the linkage acts
when you steer. A little
forward and backward motion of the axle ends doesn’t matter so when you
move the steering wheel, it translates into side to side motion of the
draglink and steers the wheels all the way to the axle stops.
This is the big deal with crossover steering, it works when you
twist the truck up in an off-road situation.
Off Road Design has the solution for our steering woes,
they offer a kit that consists of a drop pitman arm from an early Ford, a
new beefy steering arm accounting for the king pin axis inclination angle
that mounts to the passenger side knuckle, a new thick wall DOM drag link
with rod ends, and all the necessary nuts and bolts. ORD will also sell
any of the parts separately to complete your own system. Since the stock
steering box turns the pitman arm from front to back, a two wheel drive
steering box must also be used, so the pitman arm will rotate from left to
make sure your getting the best possible setup for your truck, ORD will
send out their pitman and steering arms so you can measure for the proper
length drag link, they will then build a custom drag link specifically for
with raised steering block
passenger side cap on drivers side
Installing cross over steering with a Dana 60 axle is completely
bolt on and can be done in a driveway or home garage with most common
tools although a stud remover and a few clamps could come in quite handy.
The first thing you will want to do is park on level ground and pull the
front tires to gain access to the steering components. The first thing we
did was remove the old 4x4 steering box and replaced it with a new 2x4
unit from AGR, another option is to swap out the steering sector shaft
from your old box and replace it with a new 2x4 unit, our box had seen
better days so we opted to install a new 2x4 steering box.
We removed the stock steering arm and cleaned the knuckle
surface (the area under the steering arm), next we removed the passenger
side king pin cap and installed it on the drivers side after applying some
silicone sealant to keep the spring and grease clean. We had to use a stud
remover to coax a couple of the cap studs out that were being stubborn,
otherwise everything came of fairly easy.
ORD steering arm
||ORD steering arm
||New AGR 2x4 Box
Sometimes the springs that are used to keep pressure on
the king pins will not allow the new steering arm to seat properly on to
the knuckle which was in our case. We simply used two clamps to force the
arm downward enough to get the four bolts started then tightened them down
the rest of the way. At this point the pitman arm can be installed onto
the steering box shaft, be sure to have the steering wheel centered when
you do this.
|Stock pitman arm
VS early Ford pitman arm
arm VS ORD steering arm
||ORD Dana 60
cross over steering kit
||New steering box
and pitman arm installed
Now the drag link needs to be installed and is what will
tie the entire steering system together connecting the steering arm with
the pitman arm. This is the step where a little adjustment comes in to
play, the drag link ends will need to be rotated in or out to get proper
lock to lock steering, make sure to center the steering wheel at this time
also. We turned the steering wheel back and forth a few times to fine tune
the drag link in and from here just bleeding the new steering box is all
that is left to do.
Maybe the most difficult part of this install was bleeding
our new box, because it never had fluid in it the box was full of air and
required the steering wheel to be turned full left and full right quite a
few times with the axle up on jack stands.
|New drag link
||New steering arm
installed on passenger side
||Close up of new
steering arm and drag link
||Full right turn
and left side droop with full steering control
After installing the cross over steering kit we took our
project Blazer out behind the ORD shop for a little testing. It didn't
take long to get it twisted up in the Colorado terrain, we found a spot
that allowed us to achieve full left side drop and full lock to the right,
as suspected we still had full steering control, something we didn't have
with the old bump steer system.
One of the things that makes the ORD kit stand apart from
most other kits out there is the nice flat angle on the draglink end where
it ties to the steering arm, this is achieved by milling about a 10 degree
angle into the steering arm, without this angle the axle would have
problems drooping without binding.
If you like to play in the rocks cross
over steering is a must to keep steering control of your rig at all times.
Another benefit of cross over steering is the full lock to lock steering
radius achieved due to the utilization of a longer drag link. ORD also
makes a cross over kit for the GM 10-bolt and Dana 44 axles that are found
on 1/2 ton trucks, contact them for more details. The quality
of the ORD kit is top notch and very stout which is one of the reasons why
we went with their kit along with their superior customer service. - Steve