Classic cars and trucks ask you to drive, not just point and go. Manual steering makes you feel the road surface, the front tire load, even a crowned lane on a back road. That intimacy can be addicting. It can also be exhausting in a parallel parking space or on a tight downtown turn with a large tire package. Converting a vintage car from handbook to power steering guarantees lighter effort and contemporary convenience, but not every build requirements it or gain from it. The best option depends upon your chassis, your expectations, and your tolerance for compromises.
I have installed power steering conversion packages on 1960s muscle automobiles, mid-70s pickups, and an early British sports car that fought me the whole way. Some conversions change a cars and truck and remove fatigue. Others dull guiding feel and present brand-new headaches. If you are thinking of a handbook to power steering conversion, it assists to map the entire system, not simply the pump and box, and decide whether the gains are worth the trade-offs for your particular driver.
How assist modifications what you feel at the wheel
Manual boxes and racks send road forces directly back through the column. If the vehicle is aligned appropriately and the front end is tight, that feedback reads like a tidy script. Power help adds hydraulic pressure or electrical torque to that conversation. You still guide, but the system filters and magnifies. The quantity of filtering depends on the equipment ratio, valving, and pump pressure.
On old Saginaw and Ford boxes with hydraulic assist, the feel mostly originates from the torsion bar in the input and the spool valve design. A soft valve with high pump pressure will make the wheel light at all speeds. A stiffer valve matched to a modest-pressure pump can maintain a few of the weight and self-centering feel. Electric power steering, typically column assist, has its own character, frequently lighter on center with a propensity to ravel small corrections. If you enjoy wringing out a winding roadway, you may prefer a slower ratio with firmer valving. If you primarily cruise and park, a quicker ratio with more assist may be a blessing.
Feel likewise links straight to geometry. Caster angle develops self-aligning torque, which is the natural force that wants to center the wheel. More positive caster helps stability and straight-line tracking. With manual steering, too much caster can make low-speed turns a workout. Power help lets you run more caster without the arm-busting. That is among the peaceful benefits of a power steering conversion set when the remainder of the suspension is upgraded for contemporary tires and greater speeds.
Where the conversion starts and ends
A power guiding system is a chain, not a part. Updating only the steering box and pump without thinking about the column, steering shaft, and front suspension typically results in binding or bump steer. You are signing up with pieces that were never developed to live together. A tidy plan begins with the path from the steering wheel to the pitman arm or rack and checks every interference danger along the way.
Older automobiles often need an aftermarket steering shaft with double D or splined ends that can accept a guiding universal joint. If you switch to a various steering equipment position or add a pump and hose pipes that crowd the engine bay, a universal joint guiding setup gives you angles and clearances you merely can not get with the original shaft. A compact steering universal joint with the proper splines at the box and a retractable section in the shaft can also improve security. If you have headers or a big-block with close primary tubes, depend on spending time and money here. I have utilized two-joint shafts with an intermediate assistance Manual to power steering conversion bearing to snake around tubes and oil filters on little block Chevy swaps. It is fussy work and it pays to mock up before paint.
On the front end, bushing condition and idler arm wear change how any help system feels. A worn center link or tired tie rod ends will add slop that the assist just makes more obvious. If you are going in for a steering box conversion package, plan to revitalize joints and bushings. Think about assist as a magnifier. It makes good geometry better and loose geometry worse.
Choosing your help path
Three common paths cover most classics. Hydraulic box to replace a handbook box, hydraulic rack and pinion where a rack will fit, or an electric column help that leaves the factory steering box or rack in location. Each technique has distinct strengths and compromises.
Hydraulic steering box conversion. This is the most simple on 1950s to 1970s American cars and trucks that initially offered power as an alternative. A power steering conversion set in this context typically consists of a suitable power box, a pump with brackets, a pulley setup, hose pipes, and often a new pitman arm. Bolts into the factory frame holes on many GM A-body, F-body, and B-body cars and trucks. You keep the initial center link and idler, and the feel can be tuned with box ratio and pump pressure. The disadvantages are packaging a pump on tight device drives, heat management in high-RPM engines, and the usual hydraulic leakages gradually if tubes or seals are bad quality.
Rack and pinion conversion. Numerous aftermarket packages mount a rack to the frame crossmember and provide brand-new inner tie rod pick-up points, sometimes with a brand-new steering knuckle arm to fix geometry. Done well, a rack can crisp up on-center reaction and lower play. Done inadequately, it can induce bump steer due to the fact that the inner tie rod rotates do not follow the initial suspension arcs. On Mustang II front ends and some later chassis, racks fit naturally. On 1960s full-size cars and trucks, the packaging can be tight, and header clearance ends up being a repeat culprit. A rack conversion generally requires an aftermarket steering shaft and a minimum of 2 guiding universal joints to connect to the column cleanly.
Electric column help. A compact motor and torque sensor install between the wheel and the original column lower. The steering box and linkage stay put. No pump, no belt, no fluid, less engine bay mess. Some systems utilize a controller that enables help adjustment. These work nicely when you desire reversible setup and minimal intrusion. The feel can be somewhat synthetic and the on-center weight depends totally on the software application and torque sensing unit, not hydraulic valving. If the initial box has slop, electric assist will not eliminate it. It will only make it much easier to turn.
The compatibility trap
The most typical mistake I see is mixing pieces that almost fit. A steering box conversion set constructed around a particular pitman arm drop and spline count will not play well with a random junkyard arm. Pitman arm length scales the reliable guiding ratio at the road wheels, so swapping arms to make something fit can slow or speed up the steering beyond what you desire. Also, chassis mount holes that are close rarely line up completely. Slotting a frame to make a box fit welcomes misalignment and oddball geometry. If the package expects a 3-bolt pattern with a specific clocking, withstand the temptation to hog out holes.
Universal joint steering elements are worthy of the exact same caution. A double D shaft with incorrect diameter will secure but can slip under load. Two joints can accommodate a combined angle of approximately 60 degrees, however each joint chooses to remain under about 30 degrees for smoothness. If you exceed that, you will feel a noticeable tight spot every rotation. An aftermarket steering shaft with a retractable area secures you in a crash, but it also lets you tweak length and support bearing positioning. Do not skip the support bearing if the shaft has more than 2 joints or a long unsupported period. Vibration and harmonics at highway speed will find any weakness.
Headers are the other compatibility landmine. On a little block Chevy in an A-body, long tubes often sweep right through the initial manual column shaft course. The right mix of compact joints and a low-profile shaft, properly clocked, solves it. I have actually also had to ding a main tube by a couple of millimeters to gain safe clearance. Better to modify an inexpensive tube than compromise steering geometry. Wrap and shields help keep heat off joints and boots. Grease does not like 600 degrees.
Cost and worth, with genuine numbers
Expect a hydraulic box package with pump, brackets, and tubes to run 1,000 to 2,000 dollars depending on brand name and efficiency. A rack and pinion setup lands in between 1,800 and 3,500 dollars for a well-engineered package. Electric column assist kits typically vary from 1,300 to 2,200 dollars, not counting a refurbished column if yours is used. Include 300 to 600 dollars for an aftermarket guiding shaft with a minimum of two quality steering universal joints and an assistance bearing if the geometry requires it. If you outsource labor, stores in many regions bill 90 to 150 dollars per hour. A simple box swap might be five to 8 hours. A rack conversion with shaft fabrication, pump pipes, and positioning can consume 12 to 20 hours, in some cases more if the automobile fights back.
Value is a function of how you drive. If you clock 5,000 miles a year with a great deal of in-town errands, power help makes the cars and truck feel ten years more recent. If your automobile is a weekend backroad toy that you steer mainly above 25 miles per hour, manual might be completely pleasurable with the right wheel and tire combination. If you prepare to sell, a tidy conversion that uses a known set with documents tends to maintain value better than a one-off. Buyers like serviceable parts and future support.
Tire, wheel, and positioning options that tip the scales
People chase guiding feel with boxes and racks, then bolt on a 245-section tire with sticky tread and a small-diameter wheel. Leverage matters. A factory 15-inch wheel with a thin rim offers you more torque at your hands than a 13-inch thick-rim wheel. A 10 percent modification in wheel diameter equates straight to guiding effort modification. If you are attempting to keep manual steering workable, do not sabotage yourself with a small wheel. On the other hand, a power conversion will feel even lighter with a huge wheel, in some cases too light. Balance the choices.
Alignment plays the 2nd role. Handbook cars often ran modest favorable caster, in some cases near zero, that made low-speed input manageable. If you desire contemporary highway stability and return-to-center, increase caster to +3 to +5 degrees where your shims or eccentrics permit it. Power help lets you run that caster without an exercise. Toe-in should remain modest for tire wear and crisp reaction. Excess toe masks slop however introduces heat and tread scrub. Camber can hug zero for street driving unless you press hard. Every degree you contribute to improve cornering will likewise fill the steering at parking speeds. Once again, help can bring the additional weight.
Originality and reversibility
Collectors frequently worry about cutting frames, cradles, or columns. The compromise is selecting a power steering conversion kit that uses factory holes and brackets and an aftermarket guiding shaft that secures to the initial column without long-term adjustment. If you think you might return the vehicle to manual someday, keep your take-off parts labeled and store the manual box with its pitman arm still torqued. Overlooking originality totally is great on a motorist, but the cleanest conversions leave no scars.
On cars with traditionally important front subframes, such as early Camaros and Firebirds, I choose a bolt-in power box or electric column assist over a bonded rack install unless the rack kit comes from a supplier with tested geometry. I saw a first-gen Camaro with a home-fabricated rack bracket that moved the inner tie rod rotates outward by nearly an inch. It drove fine on smooth roadways and attempted to change lanes by itself on rough spots. Fixing that later on needed restoring the crossmember and replacing the rack with a system that matched the initial control arm arcs. Reversibility has a value beyond resale, it safeguards you from pricey mistakes.
What a great kit looks like
Box, pump, brackets, and pitman arms are only half the story. Quality programs up in the little parts. Appropriate pressure and return pipes with clocked fittings that clear accessories save hours. A pressure-reducing valve or shims for the pump make ratio and valving work as meant. If the kit provides hardware, search for grade markings and proper shank shoulder lengths. A steering box conversion set that includes a matched rag joint or a spline adapter minimizes the chance of chasing after odd vibrations later.
Rack kits need to ship with intermediate shaft elements or at least comprehensive assistance on joint angles and support bearing placement. Instructions that show crossmember and oil pan clearances in actual measurements help you decide before you commit to paint. Vendors that document pump type, needed circulation rate, and target pressure assist you prevent the feels-too-light grievance. Lots of modern-day pumps flow more than vintage boxes prefer. A simple inline restrictor or a pump with correct internal valving treatments it.
Electric help sets reveal their quality in wiring and mounts. A tidy bracket that positions the system with appropriate column alignment avoids binding. Good controllers let you adjust help across a modest variety and preferably connect into lorry speed if you desire variable help. The systems that feel most natural track torque at the wheel efficiently, without an action as you cross center.
The fabrication you may not expect
Expect to make or modify at least one bracket. Even with a well-designed set, your alternator may be on the side where the pump wishes to live. Aftermarket accessory drives help, but they include expense and sometimes move the pump far enough from the crank to present belt whip at high RPM. Pick a belt width and wrap that keep the pump quiet. A screeching belt is not a tuning grievance, it is power loss and heat.
Plan the pipe routing before you tighten anything. Return lines that pass near headers will cook fluid and turn it black. On a heavy vehicle, a little cooler in the return assists on hot days. If your power steering feels fine up until a long car park crawl, then gets notchy, fluid heat is the culprit. It prevails in trucks and wagons with huge front tires.
If you cut the original shaft, procedure three times and mark the clocking. A small twist in clocking throughout 2 universal joints can develop an unequal feel. Use quality set screws with threadlocker and dimple the shaft for the set screw tips. A support bearing needs a solid mount on the frame or a made bracket from a known reference. Sheet metal will flex and send a buzz to the wheel that you will go after for weeks.
The test drive that matters
A quick loop around the block will not reveal much. A proper shakedown starts in a large, empty lot. Turn lock-to-lock at a sluggish crawl and feel for tight spots. The wheel ought to not return violently or stick off center. Then drive straight at 30 to 40 miles per hour and use little guiding inputs. On-center feel should be smooth and consistent, not dead and after that grabby. Finally, find a bad surface area at moderate speeds. If the vehicle darts or tramlines more than before, check bump guide. It is easiest to feel with hands gently on the wheel as the automobile rolls over ripples. If it darts, you need to re-check tie rod angles and inner pivot locations.
Bring tools for a pump pressure modify if your set permits it. Numerous conversions gain from a little reduction in assist compared to out-of-the-box settings. Go for a wheel that you can turn with 2 fingers when parking, not one finger, and a steady, self-centering in motion. Too-light steering feels outstanding in the garage and anxious on a highway.
When manual makes more sense
Some develops ought to remain manual. Light-weight roadsters with narrow tires steer great and feel wonderful without assist. Track-focused automobiles that run broad tires but invest the majority of their time above 30 miles per hour can get away with manual racks if you select wheel diameter and caster carefully. Spending plan is another honest reason. 2 thousand dollars purchases a lot of suspension maintenance, and a tight handbook system beats a sloppy assisted one every time.
I rebuilt a 240Z that an owner believed needed power assist after switching to 225 front tires. The genuine issue was a collapsed steering coupler and worn out rack bushings. New bushings, a fresh coupler, and an alignment with a touch less caster gave him workable effort and the feel he wanted. He pocketed the savings and later spent it on shocks, which improved the cars and truck more than power ever would have.
A sincere preparedness check
- Do you regularly fight the cars and truck in parking area or tight driveways, or is your disappointment restricted to uncommon moments? Are you happy to revitalize front-end elements and positioning so the new assist has a solid foundation? Can your engine bay and accessory drive easily accept a pump and hoses, or does an electric help much better fit your packaging? Are you comfortable making or paying for an effectively supported aftermarket guiding shaft with the ideal steering universal joint count and angles? Does the set you are thinking about preserve correct guiding geometry, or are you lured by a choice that "almost fits"?
If you can address yes to the first four and believe in the last, a power steering conversion is most likely to raise your classic.
Putting the pieces together without regret
An effective manual to power steering conversion starts with a goal and ends with an automobile that tracks straight, turns easily, and still talks with you. Map the parts from wheel to tire contact spot, not just the pump and box. Pick a steering box conversion package or a rack service that has been on the market enough time to construct a track record. Budget plan for an aftermarket steering shaft and high-quality steering universal joints due to the fact that they are frequently the distinction between a neat install and a compromise. Tune pump pressure and positioning to match your roads and routines. Protect pipes from heat and plan for serviceability. Picture and label everything you remove.
You do not need to surrender character to gain comfort. The best conversions protect feedback and self-centering while offering your shoulders a break when you ease into a tight spot. The worst conversions fix one annoyance and invite 3 new ones. Persistence in the preparation and an eye for geometry separate the 2. When you get it right, the very first turn of the wheel in a packed parking lot feels effortless, and the very first long highway stretch settles with the self-confidence of a car that is still very much itself, just easier to live with.
Borgeson Universal Co. Inc.
9 Krieger Dr, Travelers Rest, SC 29690
860-482-8283