Pulls hard left under accel

It has a half rack or maval steering rack installed,should not be affected by bump steer.

 

You'll have to explain to me how that type of steering is not affected by bump steer.
All types of steerings can & will be affected by bump steer if things are not mounted correctly ( it's all geometry ! )

 

Slinginrods, stop and listen to Mr. Eastwood.

 

Bunch of posts, bunch of ideas but no base line. Issues like this really need a picture to convey how you have built the vehicle and then closeups of some areas in question.

After reading some of the poster response one glaring item stuck out, that being the poster relocated the coil over load and then readjusted one of the upper control rods for better fitment. Readjusting a control rod would be an indication that something is out of alignment or not correctly aligned from the beginning.

If you did that something is wrong from the start. Most case I have addressed with drive steer issues can be traced back to failure to square the front and rear axles to each other and the vehicle.

My question did you and how did you square the axles to the chassis? Without doing this one axle points one direction the other points in another or severely worse, as acceleration and speed increases the tracking dynamics become more magnified.

By squaring your axles you know where your base is and then if there is an issue you can go from that point to remedy the problem.

Now your posts indicate that this happens under severe acceleration and during left turns. This leads me to focus on the chassis for hints of design or assembly defects. Left turn issues indicate that the chassis was inducing steer as the chassis rolled right. (Left side up, right side down) My question, which way do you correct by turning the steering wheel further to the left or by back steering and turning to the right?

I am interested in the location of this half rack steering box at the present time as a potential source of the steer problem since it is located on the left rail and the left rail is moving up during acceleration and up during right roll. This would have an effect on the passenger side steer arm hook up.

Post back what you checked out and see if you can post some pictures so its not a guessing game.

 

x2. If you don't know who he is, just take our word for it.

 

I know who he is.again no argument here ,the car only has a few hundred miles on it.what I found was the pre load in the four link was off.i don't have any problems with bump steer on this vehicle,and I know what bump steer is.i will try to get som pics of the steering to quell any worries that the chassis was built incorrectly.again I thank you for your input.

 

pics

 

more

 

my pics of the chassis fabrication were lost on a bad comp.but rest assured the frame was built square and true on a fixture by a reputable fabrication shop.its not uncommon for the rear 4 bars to need some tweeking.i posted before i really dug in to look at the problem.i had assumed the bars were adjusted correctly.we all know what assume means lol.

 

http://www.streetrodderweb.com/tech/1102sr_unisteer_cross_steer_kit/viewall.html info on the rack thats in the car ,

 

http://www.rodandcustommagazine.com...id_axle_front_suspension_details/viewall.html article on how cross steering virtually eliminates bumpsteer,pete chapouris ,i know who he is too.

 

Sounds like you've got some stagger in it. Run a tape around the tires and make sire the circumference is the same on both tires. Right tire being slightly larger will make it go left under hard acceleration.

 

In your photos, the car appears to have shackles on both sides. You said it has a dead perch, am I missing something? or was one installed after the photos were taken ?

 

This artical also points out the importance of a properly installed panhard bar.

 

Have you taken the car out since re-setting the rear? R&P steering on a solid axle is illegal here in NZ because of the problems it causes. Even if the tie rod is level, under hard acceleration it WILL pull to one side because of the arc it goes through, a shorter tie rod is worse.

Scotty

 

Hmm, on reading his first post it does not sound like any form of bump-steer, he would have found general twitchiness all the time if it was bump-steer - and with that set-up it would want to steer to the right as the weight came off the front suspension and the shorter arc of the rack 'pulled' on the left-hand steering arm.
My 2-cents worth given free!

 

Correct, If the tie rod rises toward the wheel it would push, which is what I should have written in my post. The photo's don't show that side of the set-up.

Scotty

 

Slingnrods, thanks for the pictures, nice car, that helps describe what you are working on. I have been following responses and without actually measuring the axle position I still feel that you are like a dog chasing it's tail. I realize that the chassis has been jig welded but usually during assembly everything is just nut and bolted together and assembled but never actually checked. Counting exposed threads does not account for accuracy. When you have indicated that you have adjusted the shock pre load that really doesn't do anything in regard to alignment issues and back to adjusting just one bar to remove bind indicated there is something amiss during assembly. Back again to sqauring your chassis I posted on another similar issue today, if you are unsure of the method of checking your vehicles axle sqaure there is a post on the HAMB done a few years ago by Brian Angus, do a search locate this post and it will outline the quick way of determining your axle position. I dont think this has anything to do with dead perches, panard rods, tire size or loads.

 

What kind of Possie or locker is in the rear diff??

Check rear tire pressure.

Light em up, make sure BOTH rear tires are getting power if you have a lsd or locker.

IF it has a locker, you could have a broken axle and not know it if it is a non C clip axle.

 

That is some useful info.this is the first car I've used this on.could this be due to the rise of the front end? Kinda makes sense since there is only one tie rod and not two like on a standard rack and pinion.

 

I know that on cross steer there is place.for these.I have never experienced the wander that can come from the tie rod causing the axle to shift. Tire size will most definitely amplify this.larger the tire width the more load induced.I run a narrow 165 80 15 tire on a4 inch wheel.it is really relative to load on the perch.did henry use those on factory cross steer?im sorry for previous post.there is No deadman on this car.past car had one.last two have not, I tried it out didn't seem to matter.

 

Will look this up and recheck everything.thanks

 

A 1902 Packard has a transverse spring, a 4-bar, cross steering & a panhard bar !


1930's driving demands were much different that today's, almost no high speed driving or cornering.
Ford went to cross steer in 1935. By 1940 they added a front anti-roll bar, which has attachment hardware that also helps control side to side movement (like a pahard does). By 1947 (or '48) Ford equipped all cars with a panhard bar (front and back).
On todays cars ,with a transverse spring & cross steering of any type,(vega, half rack, or whatever) a panhard bar or dead perch is critical ! ! (panhard bar being best).

PUT A PANHARD BAR ON IT !

OK I'm Done . . . . . . . .

Good Luck !

Pete Eastwood

 

Move the engine to the right. The relocation of the weight will make your car go straight

 

Actually two tie rods are worse because the wheels then go in opposite directions (toe in and toe out) as the front articulates through it's arcs, rather than both in one direction as with your cross steer system.

Have you driven the car after re-setting the rear?

Scotty

 

great info,that's why I asked.interesting on the Packard .my friend just built a 40 and he used a sway bar on it too.also used power steering.split wishbone,cross steer with later box .drives great.you been building them longer than me I'll look into a pan hard .thanks again.

 

Most modern cars and trucks use rack steering today,everything that comes from the factory of the brands I wrench on at the dealership have racks.i was referring to a later a arm/ strut type suspension.ive never seen a rack on a solid front axle ,although I'm sure there out there.the rack can move with the control arms and have zero bump steer ,if they are set up right.i will be driving tomorrow ,got home late.

 

The only way a r&p steering box will work 100% with a solid axle is if it's mounted to the axle - and that would require a telescopic/flexible steering column..

T-bucket style with the r&p sideways and pushing/pulling on the dirvers side steering arm on the back of the spindle is also pretty good.

But the set-up you have with half a rack pulling/pushing on the steering rem is a big as to it's integrity of keeping track of the suspension movement without causing some sort of steering action as the suspension rises and falls (whether by going over a bump on the road or the front rising under acceleration).

The end of the r&p will be moving htrough a diffeent arc to the solid axle, make no mistake about that.
Again my 2-cents worth posted free.

(Unhook the r&p arm from the back of the spindle, move theend of it (the r&p part) up and down and see what sort of arc it moves through - and then check how your axle behaves as it goes through the suspension travel, it shouldn't be moving through any sort of side-to-side arc)

 

Grab someone to video it from the front and rear, will be interesting to see.

Scotty

 

I've read the entire thread and fully agree with this post. Doesn't sound at all like a front end problem, based on your description of what it's doing. The only front end issue that I can see is the need for a panhard bar, as Pete Eastwood stated. It needs one, but I don't believe this is what is causing this particular problem.