Power steering alters the character of a lorry. On a tight switchback, during a three-point turn with a trailer, or pushing a parallel parking spot into submission, assist turns effort into precision. If your automobile or truck rolled off the line with a manual box, transforming to power help can seem like a discovery. It can also go wrong if you approach it as a fast bolt-on. Steering is a system, not a single part, and little choices waterfall into huge consequences. This guide strolls through the conversion with the same care you must bring to the job, mixing mechanical detail with the judgment that only appears after a couple of knuckle-busting installs.
Clarify your goal and your baseline
Start with your goal for the lorry. A classic half-ton pickup that invests weekends at the lumber lawn, a pro-touring 60s muscle vehicle, and a rock-crawling path rig ask different things from a power steering system. Help level, steering ratio, packaging, heat management, and dependability all track back to use case.
Your standard matters simply as much. Manual systems normally fall into two categories. One, a recirculating-ball steering box with a pitman arm, drag link, idler, and center link. 2, a rack-and-pinion layout, more common on lighter, later cars. Many manual boxes can be swapped for a power box in the exact same chassis household, in some cases utilizing a steering box conversion package designed for that platform. Manual racks are generally replaced with an assisted rack that bolts into the initial subframe, but those swaps typically require pump and tube routing constraints that differ from box-type conversions.
Measure what you have. Note the steering column shaft diameter and spline count, the input angle relative to the firewall program, and the range from the column exit to the box input. Take images of linkage geometry at trip height. Count your existing ratio by turning the wheel lock-to-lock and comparing to pitman arm travel. Catch those details now, and you prevent the most typical errors later on: mismatched input splines, universal joint bind, and geometry that eats idler bushings for breakfast.
Choosing the path power box, power rack, or electrical assist
Most store conversions fall under among 3 classifications, each with its own trade-offs.
A box-to-box swap matches classic body-on-frame automobiles and trucks with factory-style linkages. A steering box conversion package for a provided chassis typically includes the power box, proper pitman arm, frame adapters or plates, and in some cases hoses and a rag joint or a compact steering universal joint. The advantage is toughness and predictability. Parts are simple to service, and you keep the initial linkage architecture. The downside is product packaging weight and some on-center feel that can be less crisp than an excellent rack-and-pinion.
A rack swap makes sense when a subframe is compatible with an assisted rack from the exact same platform family. Steering reaction improves, and effort feels more linear. You will need to manage bump steer. With a manual rack, someone most likely shimmed tie rod ends to soothe toe change. A power rack that sits a few millimeters greater or lower can reverse that work. Plan on determining and shimming to get tie rod and lower control arm arcs aligned.
Electric column help is the third route, progressively popular on classics where area is tight or the engine has no accessory drive for a pump. An electric unit sits in-line with the column and adds torque directly to the shaft. It prevents hose pipes and pump brackets. It does not Steering universal joint fix careless linkage, and on much heavier trucks the help can feel wood if the linkage is used. For heavy-duty or high-heat use, hydraulic power still wins for resilience, particularly off-road.
Parts preparing without the surprises
A neat swap is won or lost in the parts plan. Before a single fastener moves, set out everything and test-fit on the bench.
The pump need to match your box or rack. Saginaw pumps are ubiquitous and tolerant, however circulation and pressure matter. A normal recirculating-ball box wants approximately 2.5 to 3.0 gallons per minute and 1,100 to 1,300 psi. Many pro-touring builds prefer somewhat lower circulation for better feel. Inline restrictors and various valve springs in the pump can tune assist. Order the appropriate bracketry so belt alignment is right, and ensure pulley-block size fits crank and accessory ratios. A small-pulley, high-rev setup will heat up fluid and whistle the pump.
A power steering conversion kit typically covers the huge products. In many cases, you will still require an aftermarket steering shaft or a pair of compact steering universal joints to bridge from your existing column to the brand-new box or rack input. Area shrinks quick around headers, brake boosters, and downpipes. A double-D shaft with 2 joints, or a joint and a provider bearing, can snake around challenges without bind. Universal joint guiding joints should perform at practical angles. Keep each joint below about 35 degrees and aim for balance. Unequal angles produce cyclic velocity changes that you feel as a pulse at the wheel.
Hoses and fittings decide the task\'s tidiness and reliability. Pressure is generally a crimped hose pipe with appropriate flare, O-ring, or banjo ends. The return line can be push-lock on low-pressure systems, but consider a barrier hose if temperatures run high. If you path lines near exhaust, add heat sleeve. A power steering cooler is low-cost insurance in trucks that tow or cars with long, sluggish climbs. Numerous factory setups hide a small loop cooler in front of the radiator. Add one if your package lacks it.
Fluid choice is not an afterthought. Some systems require devoted power steering fluid, some for ATF. Match the pump and box maker's spec before you buy. Mix-and-match fluids swell seals and invite leakages. If your kit consists of a steering box resealed for modern-day fluids, use what they specify.
Finally, positioning tools conserve time. A digital angle finder for the column and shaft, an easy toe bar, and a means to center the box or rack will keep you out of the weeds.
Safety and prep that pros follow
Good conversions feel boring to drive in the very best way. The actions that get you there beware, methodical, and unglamorous. Raise the vehicle onto stands at frame points, not manage arms, so the front suspension droops. Remove the battery ground to secure electronics and yourself. Mark steering wheel center and lock it with a strap so it can not spin freely when the shaft detaches. A wheel that whips with force can injure fingers or snap a clockspring in later-model columns.
Soak old fasteners with penetrant the night before. Manual boxes typically share rusty frame bolts with engine install brackets. Backing them out without prepping can twist captive nuts in boxed frames. If you feel resistance that surges, stop, heat the boss, and work the fastener gently. Cracked frames occur when somebody rushes.
Removing the manual system without damage to geometry
Disassembly has one central rule. Preserve reference points. Scribe the pitman arm on the box output shaft. Step the drag link length in between recognized points. Check tie-rod lengths and tape-record them. When you put the power system in, you will start from these references, then adjust.
Pull the guiding column coupler or rag joint. If it is the initial fabric joint, anticipate it to fall apart. That is not a flaw in your strategy. It is an indication that it was due for replacement no matter what. Split the manual box fasteners last so the assembly remains steady while you deal with linkages. Utilize an appropriate tie-rod end separator or a pickle fork where appropriate, and secure boots if you plan to reuse ends.
When the manual box is complimentary, inspect the frame area where the new box will live. Search for hairline fractures around installing holes, thin or delaminated layers on riveted brackets, and rust. If the kit includes a support plate, mock it up and examine bolt alignment before you paint.
Mounting the power system for strength and alignment
Box-style conversions depend upon bolt pattern, angle, and pitman arm positioning. Dry-fit the power box with the adapter plate if consisted of. Many chassis utilize three bolts that travel through a boxed area. Use the supplied grade-8 hardware and torque spec. On older GM frames, I have welded a perimeter sew around the adapter plate after mock-up on trucks that see snow rakes, merely because repeated side loads fatigue frames. For a street automobile, the plate and hardware suffice if the frame is sound.
Center the box before installing the pitman arm. Turn lock to lock, count the turns, then back to center. Set up the arm on the indexed spline if present. If the spline is not keyed, use your scribed marks and the drag link length to set the arm near level at ride height. An arm that starts off jagged programs up as unequal left and ideal turning radius.
Rack swaps follow comparable logic. Bolt in the rack loosely so you can push it for best tie-rod geometry. Lots of subframes have slotted installs for this reason. At this stage, procedure inner tie-rod pivot points relative to lower control arm pivots. The closer these arcs are, the less bump guide you fight later.
Connecting the column with compact, bind-free joints
This step separates tidy conversions from hacked ones. Your column output, firewall program angle, engine placement, and header tubes tell you what you can get away with. In a small-block A-body with long-tube headers, I often wind up with 2 compact guiding universal joints and a brief intermediate shaft, often with a vibrational coupling if the lorry will see long highway trips. An aftermarket steering shaft lets you cut to fit and clamp or pin to the joints. Step two times, cut when, and leave enough shaft engaged in each joint for full clamping.
Aim for a straight shot if possible. If not, divided the angle in between 2 joints with a brief intermediate shaft supported by a heim-style assistance bearing on a bracket from the frame or a stout crossmember. Keep the bearing close to midpoint to manage whip. Tighten up joint set screws with thread locker and after that dimple the shaft with a drill so the set screw has a pocket. Some contractors go even more and cross-pin with a roll pin. I reserve that for race vehicles or cars with harsh vibration.
If you recycle a rag joint for isolation, check that its bolt pattern matches the brand-new box. Numerous power boxes utilize a different input spline and flat. A steering universal joint that adjusts from your column's spline count to the box's input is a cleaner option and takes less space.
Pump installing and belt positioning that stay quiet
Pump brackets are where conversions waste time. A pump that sits a quarter degree out of airplane will chirp or eat belts. With a straightedge across the crank and accessory wheels, line up the pump pulley within a millimeter or 2. Shim brackets as required. If you changed to a serpentine system, utilize a matched pulley-block size so belt wrap stays enough around the pump. On V-belt setups, pick a belt width that matches pulley-blocks and do not force a narrower belt into a broader groove.
Once the pump sits square, mock the high-pressure line. Prevent tight S-curves that will transmit noise. Keep at least a finger's width of clearance from exhaust. On a small-block with headers near the frame, I run the pressure line inside the frame rail and utilize a heat sleeve where it returns toward package. Mount the tank, whether remote or integral, above pump level so gravity helps prevent aeration. Safe and secure return lines with cushioned clamps. Difficult lines are great for long runs in protected locations but leave flexible sections at each end to soak up engine movement.
Plumbing for reliability, not just function
Thread types trigger headaches. Lots of domestic boxes and pumps use SAE inverted flare or O-ring fittings. Racks often utilize metric O-ring. Validate before you crank in a fitting that feels close. Aluminum threads in pumps will not forgive a mismatched taper. If your set consists of adapters, tighten to spec, then mark with paint so you can inform at a glimpse if a joint shifts throughout preliminary running.
A small inline filter on the return line safeguards a brand-new box or rack from debris. Include one now and change it after the very first thousand miles. If your automobile will tow or sees long low-speed climbs up, add a stacked plate cooler in front of the radiator. It is cheap insurance coverage. If the radiator already defends airflow, mount the cooler low where it catches inbound air however does not obstruct the core.
Use the fluid the producer requires. Numerous Saginaw-based setups tolerate ATF, however boxes created around specific seal materials prefer dedicated power guiding fluid. The wrong fluid swells seals, turning your brand-new parts into weepers.
Filling and bleeding so the pump lives a long life
A dry pump passes away fast. Pre-fill the tank and some pumps through the return port before the very first start. With wheels off the ground and ignition handicapped if needed, turn the steering wheel slowly from lock to lock about 15 times. Stop if the fluid foams, let it settle, and top up. Continue till bubbles vanish. See the tank for vortexing at higher rpm later on. That indicates poor return routing.
Once initial bleeding finishes, fire the engine and hold idle. Do not saw the wheel rapidly. Alleviate it back and forth and listen. A healthy system makes a soft hiss at full lock as the pressure relief opens, not a screech. If the pump whines at center, air remains trapped or the return line ingests air at a sharp bend. Shut down, let it settle, change lines, and try again.
Check every fitting for weeps. A single drop on a paper towel under the box or pump is a sign to retorque. Tidy residue so you can spot fresh leakages after a brief drive.
Geometry checks that decide road feel
With the automobile on the ground at ride height, center the steering wheel and confirm that the box or rack is centered. If the wheel is off but the box is focused, change tie rods similarly left and right to recenter the wheel. Do stagnate just one side. That shortcuts your toe and Ackermann geometry.
For box systems, validate that the pitman arm is parallel to the idler at trip height. If one sits high, bump steer creeps in as the center link arcs through travel. Change by fixing ride height if springs droop, or by replacing worn idler bushings. For racks, measure toe modification through 2 inches of bump and droop. An easy bump guide gauge is worth its cost if you do more than one vehicle. Little shim changes can cut in half toe change across travel, which you can feel as stability on rough roads.
Torque every fastener to spec and paint-mark them. I have actually captured loose column joint set screws that had backed off a quarter turn after the first hundred miles. The paint tells the story at a glance.
Test drive protocol that surfaces issues before they hurt you
The very first drive is diagnostic. Select a quiet loop near home, no guests, no distractions. Feel the on-center. It must be neutral with a light self-center as you loosen up from a corner. If it combats to return, caster is low or package pre-load is too tight. If it darts or hunts, toe is off or there is compliance in a joint.
A gentle slalom at 30 mph exposes universal joint bind. You will feel a rhythmic notch in the wheel if angles are too steep or the joints are misphased. Under braking, keep in mind if the wheel yanks. That can be brake imbalance, however freshly changed steering geometry also reveals used lower control arm bushings.
After 10 minutes, pop the hood and check fluid level and temperature. A tank you can not touch for more than a second is too hot. Either the pump is exhausting due to excessive relief operation, or airflow is poor. A cooler and a circulation restrictor can change feel here.
Tuning assist and feel for your purpose
Assist is not one-size-fits-all. A grand touring car feels much better with moderate assist and a quicker ratio. A heavy trail rig might require complete assist but a slower ratio to keep feedback under control on rocks.
You can tune with a few simple tools. Flow restrictors at the pump outlet calm overboosted boxes. Valve packages inside some pumps let you step pressure down in 50 to 100 psi increments. Attempt small changes, then drive. A steering universal joint with a small vibration isolator puck can take the edge off a chassis that transfers too much through a welded column and solid motor mounts. Tires matter more than owners confess. A 275-width efficiency tire at 38 psi will make any system feel nervous. Drop to 32 psi and the steering mellows in a manner no box swap can replicate.
If you started with an aftermarket steering shaft and 2 compact joints to clear headers, double-check phasing. The fork ears on each joint should be parallel when the shaft is straight. Misphasing develops a speed variation that seems like play then stiffness as you turn the wheel.
Common risks worth avoiding
Every installer has a list of regrets. Here are the ones that appear repeatedly in the bay.
- Forgetting to focus the box or rack before setting the wheel, which leaves unequal turning radius and rub at one lock. Mismatched fittings that chew aluminum pump threads, fixed by recognizing thread types and utilizing appropriate adapters. Over-tight belt tension that saves a screech but cooks pump bearings in a season. Ignoring frame cracks or thin areas near box installs, then blaming the box for wander. Treating the steering as isolated from suspension. Used control arm bushings and bad alignment will ruin the very best conversion.
Anecdotes from the shop floor
A 1971 Chevelle came in with a handbook box, 15-inch wheel, and a driver who liked the automobile however hated city traffic. The owner brought a generic power steering conversion kit and wanted it set up before a trip. Throughout mock-up, the package's rag joint would have positioned the column at a bad angle around a new header primary. Instead of bending the column bracket, we utilized a compact steering universal joint and a short aftermarket guiding shaft cut to fit. The initial fit cleared with a paper's density at the header, which would have ended up being contact once the engine torqued. A small support bearing on a frame tab pulled the shaft away another 5 millimeters. Two hundred miles later he called to state the cars and truck tracked like a modern sedan, and, more notably, absolutely nothing rubbed. That extra hour of shaft work conserved him a melted boot and a sour roadway trip.
On a square-body Chevy truck used for raking, the owner desired help tuned heavy. A stock Saginaw pump ran hot and whined after long presses. We included a stacked plate cooler, changed to a somewhat bigger pump pulley to cut pump rpm at idle, and stepped pressure down by about 100 psi with a valve set, which reduced relief cycling at full lock with the blade angled. The wheel effort rose a hair, but pump noise vanished and the truck made it through a whole winter season without a single bleed.
When the aftermarket helps and when it complicates
Aftermarket steering components exist for a factor. Vehicles seldom leave enough room for ideal shaft paths, and OE parts assume stock exhaust and device layouts. An aftermarket guiding shaft with double-D sections and compact joints makes its keep in tight bays. The other hand is that more joints imply more locations to misalign or loosen up. Paint-mark whatever and recheck after a couple of drives.
A steering box conversion set can save hours if it is crafted for your precise chassis. The best packages include brackets that fix box angle, a pitman arm with the right drop to preserve center link geometry, and hoses with the proper ends. Be careful of universal kits that declare to fit many models. They often leave vital dimensions to you. If you are comfy welding and fabricating, that is great. If not, spend for a platform-specific package and prevent a winter season of going after shim stacks.
Universal joint steering hardware is robust if purchased from trustworthy suppliers. Inexpensive joints establish play quickly. Avoid mounting a joint right at the firewall where it will send buzzing to the cabin. A small length of shaft between the column and very first joint smooths feel.
Final checks and long-lasting care
After a few hundred miles, flush the fluid if it darkens and change the return-line filter if you added one. Re-torque frame and box bolts. Glance at your paint marks on the column joints. Check belt stress cold and hot, since brackets can settle a little as they discover their place. If you hear brand-new noises at full lock, withstand the routine of holding the wheel against the stop. That hammers the pump's relief and constructs heat with no benefit.
Down the line, deal with the guiding like brakes, a safety-critical system that should have attention. If you include a quicker ratio box later on or step up to larger tires, revisit alignment. A touch more caster and a hair of toe-in can transform straight-line stability with sticky rubber.
An excellent handbook to power steering conversion does more than lighten effort. It protects roadway feel, appreciates geometry, and withstands heat and time. The parts list does not have to be exotic. Thoughtful choices do the heavy lifting. Whether you lean on a power steering conversion set or piece together your own option with aftermarket steering parts, spend your effort on fit, positioning, and tidy pipes. Get those ideal and the very first parking maneuver after the swap will inform you everything you need to know.
Borgeson Universal Co. Inc.
9 Krieger Dr, Travelers Rest, SC 29690
860-482-8283