tgryphon

Oversteer on '41 Continental

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My '41 Continental has severe oversteer.  When cornering, even on a gentle freeway curve, after I turn the steering wheel to start a turn, I have to correct back nearly to the steering wheel center position to keep from oversteering.  It makes the car pretty unstable on undulating roads or in a crosswind. I have rebuilt the entire front end including spring, shackles, track bar and sway bar.  King pins, shocks and tie rod ends are OK. Steering box is not worn.  I have Coker radials all around.  I haven't done anything with the rear end, although I can see nothing obviously wrong. The only thing I notice is that there is no track bar on the rear axle as there is on the front.  I assume this is correct, but I wonder what keeps the body centered over the rear axle.  I am sure that the lack of a rear track bar, if there is supposed to be one, would cause oversteer.  Interestingly, I think Fords did have a rear track bar.  Anyone have thoughts on this or have any suggestions to correct the oversteer?

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Could something be bent or out of alignment? Check camber, castor and toe-in by a reputable shop.  I like ones run by old guys that might have seen our kind of suspension before.  Don't think rear suspension would cause unless something is really loose or mis-installed.

Abe

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The main cause of oversteer is that the back tires are losing traction. You can reduce the tire pressure in the rear tires a couple of pounds less than the front.

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Jack up ft end and disconnect drag link, make certain king pins are free, if not, you will constantly turn right then left ovr and over,  How is the " return to center" after a turn??

 

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Thanks to the three of you for your responses and suggestions.  Here's what I have done.  I checked alignment...caster and camber were OK but toe-in was off.  I corrected that but it made no difference to the oversteer.  I confirmed again that there were no problems like loose tie rod ends, binding king pins or steering box, or loose spring shackles or track bar.  Then I tried reducing rear tire pressure 5 PSI.  That made no difference either.  So I am back where I started.  Any more suggestions?

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Are your shocks working? Disconnect the arms and move them throughout the range of movement. The resistance should be the same in each direction and require quite a bit of force to move the arm.

 

What tire pressure are you using in your tires?

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You may be confusing over steer with loose steering. Excess clearance in the steering gear ( worm and sector) is a major cause of this especially considering the age. "Wandering", having to constantly correct while driving, is a sure  sign even tho the linkage and alignment are ok. There are shims under the sector shaft that many times can be adjusted to correct the mesh between the worm and sector.  Loss of the steering gear lubricant probably accelerates the wear between the worm and sector.

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This is oversteer:

 

 

Is this what's happening? The rear end is swerving wildly and out of control and spinning the car around? I can't see how a front end setup on a low-powered car like the Continental could cause that. I think we have a misunderstanding of terms--I bet you don't have "oversteer."

 

I think what you are describing is that you have to move the wheel a lot to keep it going straight, that it's wandering all over the road and doesn't want to stay straight. We had a '48 Continental that wouldn't go straight to save its life. It turned out to be the tires, but the advice above is all good. Get your front end in shape and you'll be able to eliminate variables. If you can borrow a set of wheels and tires from a different car and try it (which is how we found the bad tires on our Continental), that might be another variable to eliminate.

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My 2 cents worth,  How much steering wheel play have you got? Should be nil without binding. Radial tires are great for driving on old cars, I run mine at 38LB. on my 38 L/Z.  You could check all wheel nuts, rear axle nuts, front hub nuts  and the  front and rear spring  center " U"  bolt nuts.  Make sure the square head  center bolt is flush with the top of the hole in the frame.    

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Thanks for these suggestions.  Let me answer what I can.

 

 Shocks are all rebuilt and adjusted towards the firm side.  They feel OK, though I am no fan of Houdaille shocks.  They are very temperature sensitive.  

 

The Coker 7.00R16 tires I have at Coker's recommended pressure...41 PSI...and have just rotated them.  

 

I dismantled the steering gear last year and had to remove only one shim to take out the free play between worm and rotor.  It is in excellent shape now, doesn't bind, and I cannot see any play in anything else in the front end.

 

Matt: it does feel like oversteer on this car, even though I certainly don't corner hard enough to loose traction in the rear. For example, on an easy freeway turn I turn the wheel, say, 20 degrees to the right to start into it and then immediately need to correct back to about centerline or perhaps even a little to the left to continue my way around the turn. Since I believe the front end is in good shape, this is why I started focusing on the rear end.  It feels sort of like the transverse spring in the rear is shifting sideways and causing what I have called "oversteer."  The spring can shift sideways since there is no track bar in the rear (and never was one).  The car does drive down the highway very nicely without wandering unless there is a gusty cross wind,  In that case, I do need to correct back and forth quite a lot.

 

Regarding bad tires, I used the same tires, 7.00R16 Coker radials, on a 1941 Packard Sport Sedan, a 900 lb heavier car, and they worked well. It originally had Firestone bias ply tires and the radials improved it no end.  It was the identical situation with the Continental...It had the Firestones when I bought it and I changed to Coker radials.  No guarantee my problem isn't tires, but at this point, it doesn't seem too likely, though I certainly would like to hear more details on what you found wrong with the tires on your '48 Continental.

 

New Zealand: I've done all you suggest except check the square head bolt.  Is this the one in the middle of the spring which centers-up the spring assembly on the frame?  And more importantly, how badly were you affected by the earthquake and tsunami?

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For the record, we were using Coker radials on the Continental that was squirrely, too. Put bias-plys from a '42 Continental on it and it tracked like a cruise missile. Coker tires are shite.

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Matt:  I was afraid you were going to say that.  Now I will have to buy new bias tires.  Phui.

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Contact Diamondback for radials on your car. I've been more than happy with their tires and whenever possible, I use them instead. I just put a set on my '41 Buick, another set on my '41 Cadillac, and several other sets on a variety of cars over the past 18 months. No issues, no gray whitewalls, no odd handling or difficulty balancing them. I'm a satisfied customer, nothing more.

 

As a side note, all bias-plys are made by Coker, too...

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New Zealand calling,  Yes the spring center bolt, if not centered may cause crab walking and steer  into a corner quicker more  one way than the other, just guessing really.  Thanks for your comment about our welfare re earthquake. We are OK. hit at midnight, our bed rocked, hasn't done that for a while now!  the curtain drawstring weight  swung about and kept banging the wall. No damage thankfully to us . We are  450 miles north of  the demolished area  houses and roads. They are isolated,  access only by air or sea now. The tsunami was called off. Now its raining and stormy. Thanks for your concern. Call over some time, its usually quite pleasant. You will be welcome.  Roy.    

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41lbs of pressure may be too much for your car. I would start with all tires at 35 lbs and then start dropping the pressure about back to the factory specs 1 or 2 lbs at a time. Also check the date code on the tires, they get harder as they get older. Just because they are new to you, doesn't mean that they are newly manufactured. If this doesn't work and the tires are less than 4 years old, have them siped to improve traction.

 

With the weight distribution of your car, you should experience under-steer and it should track straight down the road.

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19tom40:  Date codes on the tires show them to be three years old.  I took your advice and lowered the pressure to 35 all around and drove the car.  Then I tried different combinations of front 32, rear 35; front 35, rear 32; both 32.  There was some improvement (tho not much) at the lower pressures.  I think now that there must be something wrong that I am just not seeing.  I think I will jack the car up and inspect front and rear one more time.

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Jack up one front wheel and try to move the wheel in the direction of turns. There should be 1/64" or less movement. If there is more, look to see where it is and replace any worn parts.

 

Next grab the top and bottom of the wheel and repeat the test. Again there should be very little movement.

 

Next, remove the rear hubs and inspect the bottom of the axle housings for wear. If you can see any pitting or wear, you should have sleeves installed on the housings.

 

If all of those are good, look unto replacing the springs.

 

Slipped belts on a radial can also cause handling problems.

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Here's an update on the problem of wander on my '41 Continental.  After following all of the good advice given by the folks who replied to this posting of last November, I went through the suspension again and found one problem: the left rear wheel bearing was loose.  It took me a couple of months to figure out how to get it apart and then repair the bearing race in the differential housing, but it is now like new. Unfortunately, that didn't change the wandering issue at all.

 

I went back to the alignment shop to confirm everything was in spec, and noticed that caster was on the low end.  Spec is 3 to 6 degrees and it was 3 degrees. That, and the alignment tech, got me thinking about the effect of caster on steering, and after talking with a few people, I came to the realization that radial tires need more caster than bias ply. So I made a shim that moved the wishbone rear attachment ball-and-socket down as far as I reasonably could, about 1", giving me about 1 1/4 degrees more caster.  That gave some improvement.  Then I tried running more air in the back tires than the front by about 5 psi, and that helped a bit too.  After this, it was better, but the car still wandered.  I think it needs about 2 (or more) degrees more caster and I can't get that except by bending the axle with an unobtainable Ford-specific hydraulic axle bender.

 

Finally, I bought a new set of bias ply tires and the wandering issue went away.  Problem solved.  In a couple of days I'm off on a 3,500 mile trip with the Lincoln so it will get a good test.

 

Thanks to everyone for the help!

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Good solution,  thanks for the information.  Mine will be road tested by the end of the week.

 

Tom

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Don't forget to check the rubber frame isolators. The crossmember that the front and rear springs are mounted to are dependent on them to hold the suspension securely to the frame.  

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Thanks for the update. It is good to hear that your Continental is driving down the road as designed. It is too bad that the vendors making reproduction tires cannot provide a quality product. I have had good luck with Coker tires, but when others have had problems with them, I always tell them to get back to Coker as he will stand behind his products. Sometimes the person on the other end of the phone needs some serious prodding to fix the problem, but I find this to be common among the larger vendors.

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