Power steering conversions are one of those upgrades you feel every time you drive. The wheel lightens, the truck stops hunting ruts, and tight parking lots stop feeling like arm day at the gym. But getting from boxes on the shop floor to a clean, quiet system that does not weep or wander takes more than following the instruction sheet. The hardware matters, the geometry matters, and the little fit-and-finish choices you make in the moment set the tone for the next ten years of driving.
I have converted everything from manual steering F100s and C10s to early CJ Jeeps and small British cars, and the same principles keep saving time and parts. Below are the hard-learned techniques that turn a generic power steering conversion kit into a tailored, durable system. I will call out common pitfalls, give real dimensions where they help, and explain where to deviate from the paper instructions without regretting it later. Whether you are installing a power steering conversion kit, a steering box conversion kit, or rebuilding the linkage with an aftermarket steering shaft and steering universal joint, the goal is the same: precise control with no drama.
Start with the right baseline
A power steering conversion never fixes loose, bent, or dry components. It only masks them until something fails dramatically. Before you bolt on the pump and hoses, set a baseline. With the vehicle on stands and tires off the ground, have a helper turn the wheel while you watch the linkage. Any motion that does not immediately move the knuckle is lash you must address.
On vintage trucks with manual boxes, the pitman arm often feels like the villain, but the slop usually lives in the idler arm bushing or center link. If your tie rod ends take more than light effort to articulate by hand, they are binding and will transmit that bind into the new system, often as a slow return-to-center or a notch at mid sweep. Worn rag joints hide as rubber dust and shiny steel shavings near the column. If the rag joint looks suspect, plan for a steering universal joint upgrade now rather than later.
Measure kingpin or ball joint play with a dial indicator if you have one. A tenth of an inch at the tire bead translates to vague steering and unpredictable feedback. The cleanest conversions start with straight, lubricated, tight front ends. You cannot tune out geometry with pressure.
Lay out the conversion on the floor
Open every bag. Match each fitting to its hose and each bracket to its mounting face. A power steering conversion kit usually contains a pump with pulley, brackets, steering box or rack components, an aftermarket steering shaft or coupler hardware, and hoses with specific ends. Verify thread types. Many domestic pump pressure ports use inverted flare or metric O-ring flare, while some steering boxes use SAE O-ring or NPT. You can ruin a port with one wrong attempt, and the leak will chase you.
Mock up the bracket set with the pump and alternator on the floor first. Use a straightedge to sight pulley alignment. If the pump pulley face is not coplanar with the crank and alternator within 1 mm, you will eat belts or hear chirps. Shim the brackets with precision washers rather than stacking flat washers randomly. A 0.030 inch shim at the bracket often equals calm belts for years. Keep notes. If the steering box conversion kit reuses a factory frame location, check the frame holes before you lift anything into place. It is common to find elongation or cracking around the original box holes on decades-old frames. If in doubt, sleeve the holes and plate the frame now, not after the test drive.
Frame reinforcement and fastener strategy
Adding assist increases forces at the box mount. Manual boxes live easy lives compared to a power box that multiplies torque every time you crank the wheel at a standstill. On classic Fords and GM half-ton trucks, I plate the frame rail with a 3/16 inch steel doubler across the box area, extending at least two bolt diameters past the outer holes. If the kit includes a reinforcement plate, use it even if your rail looks perfect. The stiffness keeps the box from twisting the frame, which feels like steering wander on crowned roads. Torque values matter, but so does thread engagement. If you are tapping into a welded nut or a crush sleeve, chase the threads and confirm bolt protrusion. A half thread shy can back out with repeated assist cycles.
Use proper bolts, usually Grade 8 or 10.9, with washers that fit the counterbores. Torque to spec, then paint-mark the heads so you can see if anything moves during the first week of driving. That little yellow line has saved people from losing a box on the highway.
Choosing and measuring the steering shaft
The steering shaft connects your hands to the road. Slop here feels like a worn box even when everything else is new. Most conversions toss the aging rag joint and replace it with a double D or splined aftermarket steering shaft paired with one or two universal joints. The temptation is to reuse the stock intermediate shaft to save time. Resist it if the bearings are gritty or the collapsible section has corrosion. A fresh shaft with a tight telescoping section and quality U-joints costs less than one alignment and will hold tolerance.
Measure from the steering column output to the box input with the wheels centered, suspension at ride height, and the column adjusted to driving position. If you need two joints due to an angle change, add a support bearing between them. A good rule is no more than about 30 degrees per steering universal joint. Two joints can handle more than one, but past about 60 degrees total you invite binding and heavy spots. If you are forced to run steep angles because of headers or engine accessories, introduce a third joint and a support bearing to split the angles. That support bearing is the silent hero. It prevents the intermediate shaft from flexing under load and keeps the U-joints at consistent working angles, which reduces notchiness and improves return-to-center.
Confirm spline counts and sizes. GM boxes commonly use 3/4-30 or 3/4-36 input shafts, while many aftermarket columns use 3/4 DD. Buy the correct couplers rather than adapters stacked on adapters. Every joint is a potential play point. Use threadlocker on set screws and drill shallow dimples in the shaft for the set screw tips to seat into. That small pocket prevents the set screw from walking as the joint sees reversing torque.
Clock the pump and plan for belt behavior
Power steering pumps behave better when they see clean belt wrap and live at a friendly clock position for bleeding. With V-belts, you want at least 120 degrees of wrap around the pulley at idle tension. Serpentine systems are less sensitive but still prefer good contact on the driven pulley. If your alternator bracket interferes, try clocking the pump reservoir to clear lines and improve hose routing. Most Saginaw style pumps let you rotate the reservoir after loosening the retaining hardware. Keep the return nipple high to prevent siphoning air when the system is off.
Pulley alignment is the headline, but pulley offset and diameter are the subtext. A smaller pump pulley spins the pump faster at idle, which helps big tires in parking maneuvers but can lead to noise or cavitation at high RPM. For street trucks and 31 to 33 inch tires, a stock-diameter pump pulley with a 5 to 6 inch crank pulley works well. For heavy off-road tires, consider a slightly smaller pump pulley, then control high RPM with a pressure-reducing spring if the box feels too light on the highway.
Hose routing that does not fight you later
Pressure lines need to clear both the engine and steering movement. Route with the suspension at full droop and full bump to confirm clearance through travel. Avoid tight 90 degree fittings immediately out of the pump or into the box, they add restriction and heat. Gentle arcs last longer and quiet the system. Use high-temp power steering hose on the return side, not generic fuel line. Fuel hose softens with ATF over time and blisters near headers.
Keep hoses at least an inch from headers and exhaust manifolds. If that is impossible, add heat sleeve and a small standoff bracket. The cost of moving a line once is small compared to the cost of replacing a cooked hose and paint after a leak. When you cut hose, use a sharp blade or a dedicated hose cutter to avoid frayed ends that compromise the clamp. Double-clamp is not a solution for a bad barb. If you see a weep, pull the hose, trim a clean end, and re-seat it.
Pay attention to fittings. Inverted flare seals at the cone, not the threads. O-ring fittings require a clean chamfer and a healthy O-ring. Smearing thread sealant on O-ring threads does nothing useful and looks messy. NPT fittings need sealant on threads, but go easy. Excess paste migrates. If you have a steering universal joint near the lines, orient the joint so the set screws face away from the hoses. You do not want to nick a hose during a later adjustment.
Fluid choice and the quiet pump myth
Your kit instructions may specify the fluid. If it does, follow it. If not, a high-quality power steering fluid is safer than ATF in modern pumps, but many classic Saginaw pumps run happily on Dexron III or equivalent. The myth is that any noise means a bad pump. In reality, most groans come from air or a poor return path in the reservoir. A return nipple that dumps fluid above the oil level, or directly into the pump inlet vortex, will foam the fluid. If you have a reservoir with multiple return ports, use the one with an internal tube that aims away from the inlet. If the return exits above the fluid, extend it with a short internal tube to discharge below the surface.
Install a small inline filter on the return line if the system is new or if the steering box was rebuilt. Early miles shed fine metallic particles that will shorten pump life. Replace the filter after a few hundred miles. That is cheap insurance.
Bleeding without the drama
A dry system is an air trap. The pump does not move air well until it primes. The fastest way to a quiet system is a gentle routine and patience. Raise the front tires off the ground. Fill the reservoir to the mark. With the engine off, turn the wheel slowly from lock to lock at least 10 times. Watch the fluid. Bubbles will appear and break, and the level will drop. Keep adding fluid to avoid sucking air down the return. Once the foam subsides, let the system sit for a few minutes. Repeat the slow lock-to-lock sweep.
When the fluid looks calm, start the engine for a few seconds and then shut it off. If the pump whines immediately, stop and let it sit. Do not rev to push air out. That only churns the foam. Repeat the off-engine sweeps, then run the engine again for longer. Continue until the level stabilizes and no bubbles appear. A stubborn system often benefits from loosening the pressure line at the box just enough to burp trapped air while a helper sweeps the wheel, then snugging it with the engine off before restarting. Keep rags handy. Clean any drips. ATF smell lingers, and it will make you think you have a leak later.
Steering geometry and the wandering wheel
A common complaint after a manual to power steering conversion is that the truck now wanders or feels twitchy. Assist did not change your caster or toe, but it made their effects more obvious. Manual steering trucks often run minimal caster to reduce effort, sometimes near zero. Power assist wants more caster, typically 3 to 5 degrees on solid axle trucks and 5 to 7 degrees on independent front suspensions, within the range the chassis can provide without causing u-joint bind or driveline vibrations. More caster improves return-to-center and straight-line stability, at the cost of heavier steering at low speed. Since you added assist, you can afford that trade.
Toe-in should be set with the vehicle at ride height, tires and wheels installed, and steering settled. Aim for a hair of toe-in, often around 1/16 to 1/8 inch total for trucks, to account for bushing deflection on the road. If your kit changed the pitman arm length or moved the box slightly, bumpsteer can creep in. Check for tie rod angle relative to the control arms or leaf springs. If the tie rod no longer runs parallel, consider correcting it with a matching idler arm drop or adjusting the steering arm. Small shims can yield big improvements.
Dealing with headers, oil pans, and the art of the reroute
Engine swaps complicate steering conversions. A big-tube header that kisses the steering shaft or blocks the box makes for a long afternoon. The solution is rarely brute force. Mock the header with the aftermarket steering components on the bench and change the sequence. Sometimes the steering universal joint near the column can be clocked to move the shaft away from a tube, or a small dimple in a header primary can gain the needed clearance without hurting flow. If the interference is near the box, a short double D shaft with a longer lower U-joint can move the joint away from heat. Keep at least 0.250 inch clearance cold. Hot parts grow.
Oil pans beneath center-link steering can fight you too. Some steering box conversion kit instructions assume a stock pan. If your aftermarket pan has a deep sump where the drag link wants to live, you may need a different pan or a revised center link. Do not cheat clearances. A pan that just kisses at full lock becomes a hole after a few potholes.
Rack and pinion conversions with column adapters
Some kits replace the box with a rack. The advantages are light weight and a more precise feel if the geometry matches the suspension. The trap is a poor inner tie rod pivot location. If the rack pivots are not aligned with the control arm pivots, you get bumpsteer that no alignment will erase. The best rack conversions provide brackets that place the rack so the inner joints land on a line through the control arm pivots. If your vehicle rides lowered or lifted, verify that relationship at your ride height, not the one in the brochure photo.
Column alignment is more sensitive with a rack because the input often sits lower and farther forward. This tends to introduce more angle at the steering universal joint set. Add a support bearing on the firewall side of the shaft. A well-supported aftermarket steering shaft resists column shake and high-frequency vibrations that feel like feedback through your hands.
Avoiding over-assist and tuning feel
Some conversions feel too light at speed. The steering box may have an internal torsion bar sized for one platform and tire, now transplanted into a lighter vehicle with smaller tires. You can tune feel a few ways. A smaller diameter steering wheel increases effort and quickens the wheel. Reducing pump pressure or flow increases effort and adds weight. Some pumps accept different flow control valves or shims to lower pressure by 10 to 15 percent. Do not choke the return line to reduce assist, that generates heat and can cavitate the pump.
If you prefer more self centering, revisit caster before chasing hydraulic changes. Often an extra half degree makes the drive effortless without killing parking ease. Also check tire pressure. Overinflated fronts feel darty. Most trucks on 255-275 width tires drive best near 32 psi cold on the street, not 40.
A short inspection routine that pays dividends
- Recheck box mount bolts, pump bracket hardware, and pulley fasteners after the first 50 to 100 miles. Look for paint mark movement. Inspect hoses for witness marks near headers or moving parts, and adjust clamps so screw heads are accessible for a trackside tweak. Verify belt alignment and tension cold and hot. A belt that tracks to the front edge hot is trying to walk off due to misalignment.
Steering column comfort and the small details
A tight system can still feel cheap if the column rattles or the wheel does not sit where your hands want it. With aftermarket steering components you control the stack-up. Set column depth so the wheel rim clears the turn signal stalk at full pull. If you use a collapsible intermediate shaft, confirm it still has at least an inch of overlap at full extension. That overlap is your safety factor in a collision and your tolerance for chassis flex.
Add a thin firewall plate or grommet where the shaft passes through. That small gasket keeps fumes out and quiets the cabin. If you install a steering universal joint directly at the firewall, angle it slightly so the joint never binds at the extremes. A joint that touches the yoke at full left or right will notch and eventually crack.
When to deviate from the instructions
Instructions exist to get most people to a good result. Your vehicle may not be most people. If your steering box conversion kit tells you to reuse the factory rag joint but you measure a steering shaft angle at 35 degrees, decline and add a proper joint and support. If the manual says to torque the pump bracket before aligning pulleys, do the opposite. Align first, torque second. If the kit provides a universal pressure hose, consider having a hydraulic shop crimp a custom length with correct ends and clocking. A hose that fits perfectly is less likely to chafe and looks like it belongs.
I once fought a persistent whine on a small block Chevy with a Saginaw pump and a remote reservoir. Three pumps later, the fix turned out to be the return tube inside the reservoir dumping right into the pump inlet swirl. Moving that tube two inches and adding a small deflector plate silenced the system instantly. The lesson sticks, small hydraulic details matter more than brand names.
Common mistakes and how to avoid them
The fastest way to ruin a fresh install is over-tightening the belt. A screaming belt is usually misalignment or glazing, not lack of tension. Aim for about a quarter inch deflection on a V-belt span with moderate thumb pressure. On serpentine systems, use a proper tensioner and watch the indicator.
Another mistake is mixing incompatible fittings. A 3/8 NPT male will thread into a 16 mm port far enough to feel snug. It will also split the casting when you torque it. If a fitting feels wrong, stop and measure. Thread pitch gauges are cheap. So are adapters when you buy them once, not after you strip a box.
Do not forget heat management. Exhaust wrap around a header tube near the box can reduce radiant heat into the box and fluid, but it also traps moisture. If you wrap, plan to inspect annually. Better yet, fabricate a small aluminum heat shield that stands off the header with a half inch air gap. Air is the insulator.
How to handle manual to power steering conversion on oddball platforms
Classic British cars, old Datsuns, and early Jeeps sometimes get creative solutions, especially when the original column is part of the chassis or the steering box bolts to thin sheet metal. The trick is to think like a load path. The wheel torque goes through the column, down the shaft, into the box or rack, out through the linkage to the knuckle, then into the tire and ground. If any part of that chain flexes, you introduce lag or slop. Reinforce thin mounting points with brackets that tie into real structure. On unibody cars, spread loads across multiple bolts and weld-in plates. On CJ frames, double the area around the box with inner and outer plates and a crush sleeve through the rail so the bolts do not pinch the frame flanges together.
For parts availability, universal joint steering components and an aftermarket steering shaft system make these custom installs Get started possible. Choose joints with needle bearings and seals if you drive in weather. Plain bush joints are fine on weekend cars but dry out on commuters. A little anti-seize on splines during assembly buys you a painless service down the road.
Final checks before the first drive
Set the steering wheel straight and center the box or rack by counting turns lock to lock and splitting the difference. Adjust the drag link or tie rod so the wheels point straight with the box centered. If you skip this, you will end up with different turning radiuses left and right, and the internal reliefs in the box may open earlier on one side, which feels like a dead spot.
Cycle through full lock in the driveway with the engine running. Listen. A slight hiss at full lock is normal as the relief opens. A groan mid sweep is not. Look for microbubbles in the reservoir when you hold just off lock. If they appear, keep bleeding. Take a short drive around the block. Return and inspect everything with a flashlight. Look for fresh weeps at fittings and the pump shaft. Recheck belt tracking. Feel the hoses near the headers. If you cannot hold your hand on a return hose for a few seconds, add heat management.
Living with the new system
The first week is a shakedown. Your hands will recalibrate to the lighter wheel. Expect to make a small toe or caster tweak after a few drives. As the tires and bushings settle, the sweet spot emerges. Schedule a quick re-torque of the box mount and bracket hardware, and mark the reservoir level cold and hot so you know your system’s normal behavior. Keep a small bottle of the chosen fluid in the truck for the first couple hundred miles. If you have to top off more than once, there is a leak you have not found.
When the system is quiet and the wheel returns to center after a hard turn without coaxing, you know the geometry is close. When the steering universal joint feels smooth through the sweep and the aftermarket steering shaft does not transmit vibration into your hands on coarse pavement, you know the mechanical side is sorted. When you can back into a tight space on one hand with a coffee in the other without hearing a whine, you know the hydraulics are happy.
A few parting tips that save hours
- Dry-fit everything before you cut a single shaft. Measure twice with the suspension loaded and the column where you drive, not where it is easy to reach. Invest in a support bearing if you run more than one joint or see any shaft deflection. It is the cheapest way to add precision and longevity.
Power assist should feel natural and transparent, not like a gadget you bolted on. With careful attention to the aftermarket steering components you choose, the angle and support of each steering universal joint, and the way you mount and plumb the pump and box, a manual to power steering conversion upgrades the entire driving experience. The steering wheel becomes a confident instrument rather than a negotiation, and every mile feels a little easier.
Borgeson Universal Co. Inc.
9 Krieger Dr, Travelers Rest, SC 29690
860-482-8283