I have a Model A with a Vega steering box. It turns noticeably harder to the left than it does to the right. I don't remember it being that way when I put it together. Somethings going on or I'm getting weaker in my left arm.Any ideas what's going on?
Did you recently break up with your girlfriend? OK, seriously now. Look under the car and check for obstructions. There was a thread by some doofus lately complaining that his steering would turn all the way one direction, and he then looked under the car and found the drag link was hitting something. You've checked, right? Next, grease all the zerks. Come back and tell us if that did anything.
Could be a number of things,I agree with the other guys but check and make sure nothing has bent,BTW Vega boxes can were out and need rebuilding. HRP
Just one idea,over time guys do mess around with tow,or adjust box or even place pitman arm wrong wrong,anyway there is a very real center designed in to your box=its there to have less play when going strait,the spot right in the center between turns{ if some how by misstake your box is not on center when the car is going dead strait,it will steer hard one way going to box's real center that maybe? If a box is adjusted when its not centered,then as it comes to center it gets very stiff. Be sure box is on center when front wheels are on center.
Teddy DeMello's '33 Tudor was looow in front. Lowest car at school, Santa Clara Hi, 1957. I 'dagoed' it 3" in front with a Mor-Drop, then flattened the front spring and reversed the mainleaf (eyes) and the wishbone was scary close to the frame rails. But it cleared... Over mild bumps and dips, the 6.40 X 15 Dayton whites actually scraped the underside tops of the fenders! I overhauled the '33 steering box when I had the front axle out, so it steered like a dream. One day Teddy came over, said it steered real hard when turning right... I put my floor jack under the drivers side frame rail, lifted it, and placed a car stand. No way would the jack go under the front...(fenders, grille...) Jacked the passenger side up, another stand, repeated it 3 times, finally high enough for skinny me to roll under with the creeper. "Agggh!!! Crap!! Shoot, Ted! There's a dead cat wedged between the axle drop and the spindle arm!" Holy crow... Took a Snap On scraper and an Indestro pry bar to peel kitty from betwixt the Dago and dropped spindle arm! ...Smelled bad, too... Rigor must have set in, that was a stiff cat carcass. '33 steered like a champ again!
Excessive castor will turn left hard, get somebody to turn left from right lock and you'll see the car rise. Turn back to right and the front goes down. An old FED will rise an inch or more if it has lots of caster, street cars not so much but it is there.
Jack up car/add safety stands. Check to be sure all steering gear moves with out rubbing anything as it moves back an forth. Take steering rod off pitman arm,an arm is on box in the right place so it will meet steering rod at about 90* when they meet when steering is strait ahead. Run steering wheel all the way one way=be sure arm is not hitting anything,. do same thing the other way,if there is no arm hits,then run all the way from one side to other counting the total turns from one side to the other{ maybe something like 4 turns?,what ever it is run steering wheel 1/2 the way back so that you are at the center of box,this is were it should be adjusted at{ an only at] { also that is the spot to set your steering wheel on is shaft so it will be strait when car is going strait. Now that your on center with your box and its adjusted,you can feel that box has less play on center and moves EZer to each side of center. Now besure front wheels are set at right tow,and then you can adjust the steering rod to hook up to pitman arm{do not move box off center as your doing that. Now with it still jacked up,move steering back an forth to feel smooth each side of center both ways.
Nope! The caster effect is the same turning in either direction. Turn to the left and that side will rise and the right will fall. Turn the other way and the opposite will happen. Roo
Don't overlook the real simple stuff, eg tyre pressures - if one is significantly lower it'll drag (but might not be noticeable, or you get used to it as it worsens) and turning against it will require more effort. Wheel bearings. Lubrication. If it used to be ok chances are it's damage / wear / maintenance related. And what everyone else has said. Chris
I dunno about that Roo, I recall the tie rod interfering with something when full left and having plenty of clearance at full right. The height changed considerable from lock to lock. I know you have chassis in front of you to look at, perhaps there is another explanation.
Might be steering arm geometry. If the axle is free to move around the longitudinal axis of the car it will definitely rise on the left and fall on the right when steering to the left as the rotation moves the outer end of the left spindle down and the right one up if there is any amount of positive caster (with negative caster the direction would be reversed). Depending on the amount of caster and scrub radius (king pin axis to tire contact patch offset in the lateral plane) the affect can vary but it will always be there to some degree. If the car has split wishbones or hairpin radius rods on a tube axle (or a stiff I beam) the effect will be masked because the axle will not rotate around the longitudinal axis of the chassis. That is why Don Long built dragsters ran 4 radius rods (like a street rod 4 bar). He also put the radius rod mounts, steering arm (from the drag link) and king pins in the same plane to eliminate bump steer. Roo
Maybe we said the same thing, rise on left. I have a model 'A' front end laying here in pieces, split bones with cowl steer. I'll mock it up later today and we'll be able to measure it. It is stock caster so the effect - if any - will be slight. I might be able to drop the bones and give the front end 10deg for a comparison.
and to make it easy on the wheel turns count put a piece of tape around the rim of the steering wheel at the top . makes it lots easier if you get a partial turn .
Let me throw a wrench into this conversation. You are steering off of the right front wheel if you are using a Vega box. In any turn, one wheel turns more than the other. In a left turn, the left spindle turns farther than the right. Conversely, in a right turn, the right spindle turns farther than the left. This is the effect of proper Ackerman theory. Based on the original post, if you do the same "work", bu use less distance, the effort must increase. Just for grins, count the total turns FROM CENTER to the far right and then compare this to the turns tot he far left. If the pittman arm is at 90 degrees when you begin, then it stands to reason that if you accomplished the same result in both directions, but turned the steering wheel less to accomplish the left turn, the you did it by increasing the effort required to accomplish it. I always add about 15 degrees to that 90 degree pittman location. That way the "linear" distance covered corrects itself. Yeah, there are the naysayers, but if you work it out on paper you will see what I'm talking about. Mustang boxes work the same way, you just need to lean that pittman arm back about 15 degrees and it corrects ratio and effort.
The OP said that when he first put the car together he did not have a problem so that shoots a big hole in this theory, and I am still trying to figure out exactly what you are trying to say anyhow. The OP made no mention of how many turns it takes to steer the car in either direction, just that is was getting harder to turn left. Roo
Yes I was aware of side steer, and the unequal distance of travel on the pitman and drag link, compaing full left to full right. But I never thought enough about every aspect of cross steer. I will have to ponder that, just like I did when Dick Spadaro talked about front ends.... You and Roo remind me of Spadaro's posts
Well...I said I don't remember it being that way. Maybe I'm just more attuned to the car now. I centered the wheels and adjusted the steering box as described above by Dana. I haven't driven it enough to see if it is the answer but my initial impression is that it feels better. I noticed too that my Pittman arm is not at 90°. It points maybe 10° toward the right wheel. Maybe it could be a leverage thing...?
I got tied up rebuilding a twin I beam front end yesterday and unable to do mockup, I'll do it today. Do you know how much caster is in your front end? Then I can match it and either understand or rule out a possibility.
Well, here you go. I mocked this model 'a' front end back up, the caster was 7degrees and I leveled an aluminum plate on the floor to measure to. My camera won't focus on closeups, but from right turn to left turn there is a 1/2" difference. Do to caster the spindle wants to go downhill, in real life it cannot because it is attached to the ground by the tire and that distance cannot change. What happens is the frame rises 1/2", you litterally raise the car when making a left hand turn. The first pic is the spindle at a normal right turn, the square is clamped. The 2nd pic is the spindle in a normal left turn and you can see the difference, its about a 1/2",
On modern cars I believe they set the caster different left to right to compensate for the crown in most roads. It makes the car track straight on a crowned road. Could that be what is going on?
OJ, you've got some bent parts. An original old Ford axle is the same caster and camber on each side. The axle is supposed to be flat, not twisted. No reason for it to raise a car on one side more than the other. That's the onliest reason for your results in your experiment.
Alchemy, the twisted axle is obvious. Good call...for most 'afficianados', this call requires the use of at least a hub gauge... I had a pit with all the 'spanners' and jacks at my command when I worked at Reinegger's frame & wheel in San Jose...right after I left, they sold "all that old crap". The NEW owner was an 'experienced' front end man. I called him a 'shim shuffler'...
I do not have bent parts, it is a simple demonstration. The axle really has nothing to do with it other than it holds the kingpin, I can cut the axle off just south of the perchpin and it will have no effect. The kingpin is inclined 7 degrees and that is what the spindle rotates around.
OJ, if it twists, you must acquit. Measure the caster and camber on both sides of your axle with a real gauge, then get back to us. Sorry Motoguy for jamming up your thread with all this nonsense. I just hate to see inaccuracies spread as gospel.
Alchemy, the gauges tell a lot, but I've used OJ's method and had good results too. Assuming we keep the big picture in mind.
Alchemy, I know you are an experienced guy, I can only assume you are misreading the nature of the thread and what I am illustrating. There is another current thread on the issue of caster and it's affect on being hard to steer. The thread is called something about 'positve caster'. Just to be clear, the spindle in the picture is the left spindle. The first picture is normal position for a right turn and then the same spindle aimed for a normal left turn. You are not looking at different ends of an axle, it is the same spindle in both pictures showing how is changes latitude as it goes thru its' right to left turn axis.
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