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Steering 101

Steering 101

Information courtesy of Borgeson Universal.

Steering System Design
Often the steering system is designed late in the building process. We recommend that the steering be mocked up at the time the engine and exhaust components are installed. Positioning of the column, shafts, and u-joints with respect to the engine, exhaust and steering box early on can help in selecting the correct parts. With our wide selection of u-joints, shafts, and vibration reducers, any system can be designed or modified to result in a car that is not only safe, but a pleasure to drive. Keeping a system simple is the best course, but even a system with up to 10 u-joints can be designed as long as the proper phasing and supports are used. Remember to use a support bearing if more than two joints are used.

Shaft Support Placement
Any time more than two universal joints are used in a system, a shaft support is required to prevent the shafts from looping. In a system with 3 u-joints, one support is required. For each additional u-joint, an additional support will be needed. In a 3 joint system it is best to locate the shaft support as close to the center u-joint as possible. If one of the shafts is significantly longer than the other, it is best to locate the support on the longer shaft.

Vibration Reducer Placement
Vibration reducers can substantially reduce, and even eliminate annoying road vibration from being transmitted to the steering wheel. Location of the reducer in a system is very important in order to take full advantage of its effects. In a two joint system, the vibration reducer can be installed at either end without any loss of effectiveness. In a system with one or more shaft supports however, the vibration reducer should be located on the column side of the supports. A shaft support located on the steering column side of a vibration reducer can pick up vibration, bypass the reducer, and transmit the vibration to the steering wheel.

Shorty Columns
A great way to free up some much needed leg room in your street rod is by using a shorty column. This moves the steering column up under the dash and gives you much more leg/pedal space resulting in a much more comfortable ride.

Steering Column Length and Column Drop Size
Before determining the column length, it is important to have your seat and pedals in the final locations. Using a pie tin tacked to a wooden dowel is an excellent way to decide on steering column position and length. With one person sitting in the car and holding the “steering wheel” in position, another person can take measurements of column length and position. Keep in mind, our traditional style steering wheels are flat, while our Forty Style and Banjo wheels are dished approximately 4”. This is also the perfect time to determine how much drop you’ll need to put the column in a comfortable driving position. Measure from the mounting surface on the dash to the center of the steering column. This is the length of the drop you will need.

Steering Box Installation Angle
One thing frequently overlooked when building or modifying a car is the position of the steering box. Steering boxes are often positioned with the input shaft level creating a much more complex steering linkage. A great way to simplify your steering linkage is to position the steering box with the input shaft angled up toward the steering column.

Steering Ratio
The steering box ratio is the relationship between input motion and output motion. The ratio is expressed as 24:1, 22:1, 16:1, etc. For example, in a 24:1 ratio box, the pitman shaft rotates one degree for every 24 degrees of input shaft rotation. The higher the first number, the more input shaft rotation is required to get the same amount of output shaft rotation. Dividing the first number in the ratio by four, gives the number of turns lock to lock.

Pitman Arm Length
Steering speed can be adjusted by box ratio or pitman arm length. The longer the pitman arm, the quicker the steering will be. That is, a longer pitman arm means less steering wheel movement is required to produce the same amount of front wheel movement. So if you are looking to speed up or slow down the steering, changing the pitman arm is an easy way to do it.

Determine splined shaft length with two u-joints:
1. Measure the distance from the end of the column to the box/rack (Dimension C).
2. Subtract 3” from this measurement.
3. Order the next even size shaft (Dimension B).
Note: We stock stainless and polished stainless shafting in 1/4” increments up to 24”

EXAMPLE If “C” is 18” —subtract 3” (1-1/2” for each joint). “B” is 15”. Order a
16” shaft and trim a total of 1” from the shaft, either from one or both ends.

Determine splined shaft length with one u-joint and u-joint/vibration reducer combination.
1. Measure the distance from the end of the column to the box/rack (Dimension C).
2. Subtract 4” from this measurement.
3. Order the next even size shaft (Dimension B).
Note: We stock stainless and polished stainless shafting in 1/4” increments up to 24”

EXAMPLE If “C” is 19” —subtract 4” (1-1/2” for a joint and 2-1/2” for the vibration reducer). “B” is 15”. Order a 16” shaft and trim 1” from the shaft, either from one or both ends.

Determine splined shaft length with three or more u-joints.
1. Buy the u-joints first.
2. Install a joint on the column and one on the box/rack.
3. Use dowels or PVC pipe and mock up the system around obstacles.
4. Order the correct shaft lengths based on dowel/PVC lengths.

Rag Joint Angles of Operation
Rag joints are designed to dampen vibrations, they are not designed to accommodate an angle. If you do not have a straight connection a rag joint should NOT be used.

U-joint Angles of Operation
The Borgeson 16 series u-joints will operate smoothly up to 35°. The 16 series double u-joints will operate smoothly up to 70°. The u-joints must not be altered in any way. Pin and block style u-joints will operate at 30º smoothly.

Figure A

Splines and Irregular Shapes: the STRONGEST Method.
Detroit uses irregularly shaped shafts such as splined or a Double D configuration and inserts them into a similarly shaped hole with practically no play and then secures them by staking or clamping. Since steering failures are practically unheard of in modern production cars, one should strongly consider this method as having significant merit. Borgeson offers splined shafts and joints which give the option of easy disassembly when repairs on the vehicle become necessary. Another advantage is the ability to rotate the shaft in relation to the u-joint in small increments. This makes it easier to position the u-joints in the correct relationship to each other.

Figure B

A flat should be filed on the splined shaft where the set screw will clamp (figure A). This will prevent damage to the spline and allow for easier disassembly. Always lock the set screw with a lock nut, Loc-Tite or similar product. The shaft must be flush with the inside of the yoke (figure B), not so short that it sacrifices strength or so long that it interferes with the center workings of the joint.

Figure C

To determine the spline size of a component, measure the outside diameter and count the number of splines. If there is a flat spot on the shaft and some of the splines are missing, (figure C) count halfway around where there are splines and double that number. We need to know how many teeth are in a theoretical full circle. If you have something unusual or you’re unsure about measuring the spline, make an impression of it in clay and send it to us. 

Figure D

A Double D (figure D) shaft has two flats on the shaft that correspond to two flats in the female end of the u-joint. The disadvantage of this style is the lack of adjustability because the shaft can only be rotated 180°. The Double D shaft should have a dimple machined on the shaft for the set screw to clamp to (figure D).

Common practice is to use two 3/16” diameter roll pins in each yoke at right angles to each other and approximately 3/8” apart. (figure E) An even stronger connection can be made by using hardened shear pins. Pinning can be used when the shaft can be removed from the vehicle and supported properly when inserting the pins. Driving pins in while the assembly is in the car could cause damage. The major drawback to pinning is that a 3/4” diameter shaft is weakened by 30%, smaller shafts are weakened to an even greater extent. If you are considering using bolts instead of roll pins, don’t. NEVER USE BOLTS! Always use roll pins. Roll pins are driven in and fit very tightly in the drilled hole. Bolts often fit loosely inside the drilled hole and repeated back and forth movement, even though very slight, can cause the bolt to work harden and fail. CAUTION: It is unsafe to pin joints to tubing!

CAUTION: Collapsibility
Every steering system should include some means of directing energy away from the driver in the event of a collision. One method of reducing the chance of this happening is to intentionally design angles into the steering system so that the force of a collision deflects the column away from the driver. A second method is to use the Borgeson telescopic intermediate shaft.

Here is a straight column WITHOUT a collapsible intermediate shaft. In the event of a collision, a vehicle without a collapsible intermediate shaft the column is forced into passenger compartment.

Solution: A
With a telescopic intermediate shaft the column slides together, compacting before it gets a chance to enter the passenger compartment.

Solution: B
Here is an example of a steering system with angular collapsibility. An angle designed into steering shaft deflects the column upward upon impact.

CAUTION: Shaft Size
BORGESON DOES NOT RECOMMEND USING LESS THAN 3/4” DIAMETER SHAFTS All Borgeson spline and DD shafts are 3/4” diameter. We will not sell a shaft with a smaller diameter due to safety considerations. A 5/8” shaft is 42% weaker than a 3/4” shaft and can be twisted with a 14” steering wheel.

Correct Phasing

Incorrect Phasing

U-Joint Orientation
When two joints are used on a shaft, the forks of the yokes closest to each other should be in line, or “in phase.” Premature wear or binding can result if the u-joints are not phased properly. Sometimes if the u-joints are at a severe angle, even if they are phased correctly, a hard spot in the steering may occur for no apparent reason. If this happens, index the u-joints two or three splines in one direction. The hard spot should disappear or be minimized.

CAUTION: Do Not Use Flex Cable
Another less common (and definitely not recommended) method of getting from the column to the rack or box is to use flex cabling from a Pinto (this cable is no longer available from Ford). Ford only used these for a couple of years before switching to joints and shafts, which should tell you something. When a heavier engine is put into a larger heavier car, a flex cable is not reliable.

CAUTION: Welding
Welding joints is a common practice in racing, however, it is not a method we at Borgeson would recommend. Hairline cracks, which may be all but invisible to the unaided eye, could cause a weld to fail under severe stress. It may also be illegal in some states to weld steering system components on a car used on the street. Improper grounding can cause damage which will result in the failure of the steering. Overheating, which can occur at relatively low temperatures, can distort the yoke and melt the grease out of the needle bearings or damage the seals. This can prevent the joint from operating freely and it may fail. Cooling a weld too quickly can cause cracks, leading to sudden failure. Also, welding is a permanent connection that makes disassembly almost impossible should it become necessary. Caution: Welding on steering components is illegal in some states. Check first.

CAUTION: Keying and Set Screws
Using a key, as is done in many industrial applications, can transmit power effectively from the shaft to the joint. A key, however, is not suitable to take sudden shock (such as from a pothole or accident) which can distort or shear the key or shaft keyway. This may cause play to develop in the system or, even worse, failure. It should be noted that in industrial applications, keys are designed to shear, preventing damage to expensive components. In automotive applications a sheared key will cause extensive damage by causing a loss of control of the vehicle. Set screws should never be used to secure smooth bore joints. They should only be used as a method to prevent a splined or Double D shaft from disengaging from the joint. An indentation or flat should be made for the set screw on splined or DD shafts.

CAUTION: Corvair Steering Boxes
Corvairs were rear-engined cars; this means there was very little weight on the front tires. The steering box used in these cars was a very light duty box. It is not recommended for use in a street rod with the engine in the front. Steering gear failure could cause a severe accident.

CAUTION: Vega Steering Boxes
We recommend a maximum weight limit of 2400 lbs. for a vehicle using a Saginaw 140 (Vega) steering Box. We recommend the 525 Saginaw box for vehicles exceeding 2400 lbs.

Diagnosing Power Steering Problems
When trying to determine what is causing a problem in your power steering, keep this in mind. If the problem occurs only in one direction, the problem is probably in the box or rack. If the problem is in both directions, it is most likely the pump, dirty fluid or hoses. Be sure there are no kinks or obstructions in your power steering hoses and that they are the right inside diameter for the application.

Dirty Steering System
Before changing any single component of the steering system, inspect the cleanliness of your system. Dirty or black fluid can quickly ruin new steering components. If changing the box or rack, rub your finger on the inside of the reservoir. If it isn’t clean, you must flush the pump and hoses with clean fluid before installing new components.

Bleeding Power Steering
All power steering systems are designed to be self-bleeding, but sometimes they need a little help. After installing new components, fill the reservoir and let it sit for a few minutes. Raise the front end of the vehicle and turn the wheels back and forth slowly with the engine off to allow the steering box to draw fluid. Keep the reservoir full. When the fluid level stops dropping, start the vehicle and continue turning the wheels. When the fluid level remains constant the system is fully bled. Put cardboard under the front tires while testing your steering system. The cardboard will slide on the floor and prevent wearing flat spots on the tires from excessive turning of the wheels while not moving.

Steering Box Adjustment
All Borgeson steering boxes are set at the factory to the proper specifications. Any adjustments of the box beyond that will void the warranty and cause premature wear on the steering box. Please do not try to adjust your steering box. Please contact us if you feel your steering box needs adjustment.

Power Steering Pressure
GM power steering pumps will produce up to 1,500 PSI. We recommend 1,200 PSI for steering box applications and 800– 900 PSI for Mustang rack & pinions. If a pump is generating too much pressure for the rack or box you are using, the steering will be over assisted resulting in twitchy steering at speed. This can be corrected by adjusting the pumps internal pressure valve.

Many factors influence power steering troubleshooting. Here is a list of common steering and driving complaints their causes and some suggestions to fix it.

Road Wander:
Vehicle wanders left/right without any definite input from the steering wheel requiring constant
small correction to drive straight.
•Low or unequal tire pressure.
•Steering linkage from column to box or rack loose or worn
•Front-end alignment out of specification. (Inadequate positive Caster)
•Steering box or rack worn or out of adjustment
•Steering tie rod ends worn or loose

No Recovery or Return to Center:
Vehicle fails to return to center after a turn or requires steering input to return to center.
•Binding of steering linkage or components
•Front-end alignment out of specification. (Inadequate positive Caster)
•Steering box or rack improperly adjusted.

Over-steering / Darting:
Vehicle over steers and is overly sensitive to all steering wheel input requiring constant correction.
•Excessive P/S pump pressure / miss-matched components.
•Steering linkage from column to box or rack loose or worn
•Steering box or rack worn or out of adjustment

Lost motion at steering wheel:
Excessive free play felt in the steering wheel before the wheels actually begin to turn.
•Steering linkage from column to box or rack loose or worn
•Steering box or rack worn or out of adjustment
•Steering tie rod ends worn or loose
•Steering gear loose on frame

High Steering Effort in both directions:
An abnormal amount of force is required to turn the wheels in both directions.
•Low tire pressure
•Low P/S fluid level
•Insufficient P/S pump pressure and flow
•Excessive P/S fluid temperature
•Binding of steering linkage or components

Intermittent / Loss of power steering:
After servicing the P/S system you experience either a loss of power steering or intermittent assist.
•Low P/S fluid level
•P/S Belt broken or slipping
•Air trapped in the P/S system
•Dirt or contaminants trapped in the P/S pump bypass valve

Borgeson Universal
91 Technology Park Drive
Torrington CT, 06790

Published Dec 7th, 2015

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