Has anyone ever had the problem of their car pulling to one side after letting off the gas after a hard acceleration? My model A pulls to the right pretty noticeably when I let off the throttle. Any help would be appreciated. Thanks
Sounds like possibly a rear suspension component is shifting under power and not returning...look for loose bushing, bending or cracked brackets, anything with play or impending failure. I would not roadtest the problem another 10 feet before examining everything!
look at all the car go over with fine tooth comb. That,s a good way to get killed. lookTHAT THING OVER BEFOUR THE REAR FALLS OUT... MARRY XMAS AND BE CARFUL...
Definetly look it over for loose or broken parts. Every had a good wheel alignment done? Also remember that most roads are crowned in the middle for water drainage. Easy way to check this is to pull into the left lane and see if it pulls left. Could also be a tire pull, swap front wheels side to side and see if it goes the other way.
Something in the rear end is out, either a lot of play or alignment problem. On our low 7 second drag car we actually put a small amount of preload in the right rear so that when the driver lifts, it doesn't do what it sounds like your car is doing. Find out what it is before driving it any more. Lives are at stake here.
...........what they said, remembering that a couple of responses have been on rear suspension only. It definately could be at either end, or even both front and rear! Front side sway could be introducing sway-steer component, with all the things that could cause that. Further, consider frame twist, etc. etc. Yikes!
It's most likely bump steer. Local guy had this problem. Got to following him and when he nailed the loud pedal, the car pulled to the left and when he let off, it went to the right. Hairpins and a unreversed Corvair box mounted under the frame rail on a T-bucket. The pivot points for the hairpins and the drag link were about 6 or 7" apart so there were conflicting arcs when the front end of the car lifted on acceleration and the same on deceleration. He switched to four bars on the front and they made a world of difference in how the car drove. The bars and the drag link were pretty close to parallel and nearly the same length.
Most likely from frame twist it will move your steering rod enough to pull it to right when frame recovers from a twist from motor torque.
Thanks for all the info. It's really shedding some light on this. I am going to take a look at all of these things and probably do a good rebuild on an old steering box to boot. If anymore ideas come up let me know.
If you have a positraction rear and have the wrong gear oil in it it will pull to one side . make sure you have a gear oil with posi additives. you can jack one side off the ground and spin one tire to see if the other turns along with it. if you recently changed the gear oil, that might be the cause.
Ok, I've checked this thing over in the rear. No broken welds, all bolts tight, nothing bent, and everything is solid on the rear axle. By the way this is not a hard pull. Just a slight wander when you let off. Also I am running a mild 51 Merc. flathead with a 34 toploader tranny, so we're not talking massive horsepower. I do have quite a bit of play in the steering. It's an F1 that needs to be rebuilt I am pretty sure of. The steering is good, but a fresh box would do wonders. I am wondering if the play in the steering may be some of the culprit. The rear is just a standard 41-48 Ford with the rear arms off the torsion tube. Nothing there moves either. I am going to keep checking it over and then check again.
I am with you on this problem. Sounds like bump steer when the suspension "unloads". Conflicting arcs will definately cause this reaction along with other more obvious problems such as worn components. Tex Smith's book "How to build a Hotrod" covers a lot of this suspension / steering stuff in laymen's terms.
With the information that you've given, I would agree that the geometry of your front steering could be off. But I would say that would only be if you have enough power in the flatty to either partially or totally unload the front suspension. Not necessarily carry the hoops, but unload it enough that your drag link geometry in relation to your wishbone/hairpin mount and the length of the wishbone/hairpin vs. the length of the drag link could come into play. Some nice photographs, straight on profile and low, so we're all looking at the drag link and hairpins/wishbones would help us all a bit. If this car had a larger mill, I would have pointed you to the rear suspension in a minute. Dragsters are all prone to dart one way either on launch or at the big end of the track when the driver takes his foot off the loud pedal. That's what wheelie bars are for. Kevin
When its wet out you also learn to coast through the tight turns. Ask me how i know......but they do work.
In the dirt track racing world they call this rear steer. The rear end scews under acc and doesn't return to the straight ahead mode. Check the geometry and all components for binding including the shocks. >>>>.
Steering box is worn (as you said). Probably slightly out of its sweet spot (a bit to the left if its pulling to the right). Quick fix would be to turn it a bit and find its soft center. Then adjust the tie rods to center the wheels. Just a thought. Merry Xmas!
I had the same problem once. Turned out to be uneven tire pressure in the rear tires. One had 20lbs. in it , and the other 30lbs. I set them both at 30, and car was fine.
Dirty2 I'm really not sure. I've only had it on the road a couple of months, and haven't had much time to get out and do a whole lot of road testing. I'm guessing it may have been doing all along. I haven't really laid into it real hard because I've just been feeling things out since the build up. I've finally got a few days off ahead and some good weather so I'm planning on getting this thing figured out.
That actually looks pretty good to me as far as the wish bone pivot and the drag link followoing the same line. Another thing I just thought of after some guys mentioned the tires and lockers etc. Measure the circumference of the rear tires and compare them. Sometimes they can vary a great deal and if you have a posi or locker, it will give you major handling problems. It happened to a cousin of mine with his '32 roadster.
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