Caster?

Ricosan

Ricosan

Senior Member
Hey Guys,

I’m having trouble with my steering. When I make a turn, the steering wheel has to be manually returned to the straight forward position.

I made up a crude instrument to measure the caster in the front wheels. I got measurements of 2.5 degrees on the left side and 0 degrees on the right.

Are these acceptable figures?

Richard
 

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Hey Mart,

I used the instrument pictured below. I know it’s crude and the accuracy could be questionable but I just wanted to get an idea of what may be contributing to the flat steering.

I carefully placed the two legs on the a straight mahogany stick with screws. I placed the two legs against the rim and measured the angle.

I took the measurements vertically.
Richard
 

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On all the customer straight axle chassis I've built over the last 40+ years I have recommended 5-7 degrees of caster. I have recommended 1/8th of toe in for radials and 3/16th for bias tires. Seems to have worked good all these years.
 
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Ricosan said:
Hey Guys,

I’m having trouble with my steering. When I make a turn, the steering wheel has to be manually returned to the straight forward position.

I made up a crude instrument to measure the caster in the front wheels. I got measurements of 2.5 degrees on the left side and 0 degrees on the right.

Are these acceptable figures?

Richard
Click to expand...

From your description of the issue you are experiencing, it sounds as if the toe-in is not correct. Not enough toe-in will hinder the front wheels from returning to forward position.
Positive caster will make it difficult to steer.
 
Hey Mart,

I used the instrument pictured below. I know it’s crude and the accuracy could be questionable but I just wanted to get an idea of what may be contributing to the flat steering.

I carefully placed the two legs on the a straight mahogany stick and attached them with screws. This allowed me to bypass the hub cap and maintain a straight line from one rim side to the other. I placed the two legs against the rim and measured the angle.

I took the measurement vertically.

Richard
 
Stick your small magnetic protractor to the flattest spot of the front of the axle. Maybe span over the web. That will show you caster. I don't know what Henry built them to, but as Gary said 5 to 7 degrees will give you a nice steering effort. But it's rather involved (requires butchery like cutting and welding) to adjust caster on a Ford wishbone.
 
kartrae7 said:
Not saying its accurate or not but if measured on side of wheel you measured camber not caster.
Click to expand...




Correct. Camber is the relationship between the top and bottom of the wheel. Positive camber means top of tire/wheel is tipped outward compared to the bottom.

Caster is the angle of the kingpin in the front axle. Positive caster will have the top of the kingpin rearward compared to the bottom.
 
Maybe your problem is related to other components. How's the steering box and tie rod ends condition? If they are not smooth, I can see how it won't want to return to center.
 
You're measuring CAMBER, not CASTER.

Caster would be your king-pin inclination angle (how many degrees "tilted" to the rear). A simple crude way is to take your angle gauge and put it on the back of your I-beam axle (against the two i-beam ribs - middle of the axle).

This should give you the angle of the axle itself - which should be the same as the king-pin inclination angle.
 
Ford documents stated 4.5 to 9.0 degrees positive camber. The rule of thumb was to shoot for 7 degrees, roughly the halfway point.

You can actually calculate caster from the camber angle rig you made up. The math is complicated, so the process I will describe is to simply determine if caster is positive or negative, and if left and right caster are approximately equal (they should be, unless the axle is twisted.)
1) Roll down the driver side window.

2) Put a jack under the center of the axle and raise it so that both front wheels are just barely off the garage floor by an equal amount. Adjust the jack location left and right as needed to accomplish equal tire clearance from the ground.

3) With the wheels straight ahead, use your gadget to measure and record the camber of the left wheel.

4) Without disturbing the car, turn the steering wheel all the way to the left turn and measure the angle again, and record. If caster is positive the angle you record will be larger than the straight-ahead camber. If camber is negative, the angle you measure will decrease. Not good.

5) Turn the wheel full right turn and measure the angle. If you have positive caster, it should decrease from the straight-ahead camber.

6) Subtract the full left number from the full right number. Your caster is bigger than that number, but at least you know whether it is positive or negative. Guestimation? - your caster is three times the difference calculation.

7) Repeat for the right front wheel. Hope that the results between left and right are similar.



Because the change of angles is small, you need to accurately determine small changes in angles. If your gauge can not be read accurately to a tenth of a degree, you will need to purchase a digital inclinometer.



Okay, I have never actually done this, but it should work.
 
1934 Ford right? take this how you please...whilst I have no first hand experience with 34's, I have considerable experience with 35 Fords. 35-36 fords, by the design of their steering boxes, need to be steered in and OUT of a turn. I'd imagine 34's are the same. Fitting a 37 or later model steering box into a 35-36 is like fitting power steering, and the car steering will self centre coming out of a turn. 37 and later steering boxes are worm and roller, earlier steering boxes are worm and sector. Much more friction with worm and sector. I think you'd need to fit say, an F1 steering box [worm and roller] to achieve the same effect.
 
Kube said:
From your description of the issue you are experiencing, it sounds as if the toe-in is not correct. Not enough toe-in will hinder the front wheels from returning to forward position.
Positive caster will make it difficult to steer.
Click to expand...


I could be really wrong here but you want a slight toe out of 1/4". A toe out will give you drag to right wheels were a toe in won't.



With the drag link behind the axle gives it the self righting properties. A property of inertia.
 
wouldn't be the first time Alan. but then again i don't have to return my steering to go straight.
 
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I’m back.
Thanks for all your helpful comments about my steering problem. Apparently it’s a camber I am trying to measure.

I measured the degree and here is what I got. Left front wheel right turn -6.5 degrees, left turn +1 degrees. Right front wheel right turn -9 degrees, left turn - 1/2 degrees. I tried to find a digital inclinometer but the were over $50.

While doing taking these measurements I noticed that the whole steering setup is very loose. I grabbed the front tire at the 90 and 180 degrees and shook them. They moved easily an inch either way! Up and down was tight. I was planning on resetting the toe in this afternoon but with the steering this loose I don’t think there is a chance of setting it accurately.

My brother is coming by this afternoon to turn the steering wheel while I look from underneath.

Richard
 
Sounds like the most important thing is to figure out where the looseness is coming from. Either parts are worn or things are not adjusted correctly . . . or a combination of both.

You may have issues in your tie-rod ends and/or pitman/steering arm ends. These steel balls, cups and springs do get worn and/or may not be correctly tightened. Also, your steering worm and sector can be worn and the play is coming from the steering box.

On these old Fords, it is usually a combination of multiple things - and outside of the steering box itself, not terribly difficult to replace parts and get things back to spec.

Best of luck, keep the questions coming!
B&S
 
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