Pitman arm/ cowl steering woes/questions

bad picture but here is the setup..

a 36 pontiac box setup in the cowl. trying to get it level, and ride better.

is a longer pitman arm going to hurt it more than help it? it has a little death wobble at low speeds, i figure its going to help it as it will decrease the amount of wheel turns to actually turn the wheel.

but. im an idiot. like. when you start talking camber, toe-in etc. i go look at boobies, thats how much of an idiot i am. im trying to learn though....take that into consideration and call me a dumbass behind my back

i posted in classifies looking for a longer pitman arm so if ya got one i can give a try.......









i drove it from Albany area new york, to central NJ, over 100 miles....speeds of 30 in traffic to 65 highway...so it doesnt handle THAT bad, but its a little rough, especially at low speeds or if i hit a little bump.

 

suttin like this work?

 

i like boobies too....

the longer pitman arm will increase the rate at which the steering reacts to the wheel being turned

think of it like this...imagine it like this
we'll groupe pizza with boobies since its good to have both at the same time

anyways if you have a small pizza (aka short pitman arm) the crust for each piece is shorter then if you have a large pizza (long pitman arm)

so for that same 45degree piece of pizza(rotation of arm) your drag link will travel farther (length of crust) inturn making your front wheels turn farther

if you lengthen the arm on the spindle also so that it has the same ratio of lengths then your steering wont be affected

your probably right in that the downsloping drag link is causing the steering to act up
i've seen that in alot of cowl steering on cars in order to keep the box up out of your way in the interior and have the drag link lower you can find a slower acting box maybe like a 47-54 chevy truck box to replace it with then you can run a longer arm and it will work out to the same ratio

i hope im making some sence...im trying to think straight but youve got boobies on my mind + ( o )( o ) =

good luck
zach

 

yeah i get the part about increasing steering with fewer wheel turn...

anyone up for doing to the math and have info on a 36 pontiac steering box and say a 11 inch pitman arm, an dsee if its going to work or not?

it seems now it take a little too much turn on the wheel to make turn, but i have nothing to compare it to.

 

see all that thinking about boobies made me miss that you said decrease the wheel turns....i read that as decrease the amount the wheels turn

sorry
anyways good luck
zach

i just though...if you think its too slow you could just lengthen that arm a little and then make a new mount for the spindle that bends up hill

look at the rollingbones cars..their spindle bracket is bent like a Z

 

I don't know if you've thought of this or not.

I see that the steering arm on the spindle is bent up a little. Perhaps you could make a new one that is higher(more bend to it) so the drag link is more level? Or if you found a pitman arm that was shorter than 11" but longer than the one you have now, you could make up the difference with the steering arm on the spindle by heating and bending.

Woody

 

you are looking in the wrong area of the car. the up ward angle will only effect the bump steer. death wobble is more of a bad part or wrong kingpin angle. start by checking the front end for play(tie rod ends, king pins, wheel bearings) next check the angle the king pins are set at should be 6 degrees +- 1 degree . next the toe should be about 1/8 toe in (if you measure the from tire to tire in the middle fron and back)

 

oooohh boooobiess..........


bump steer/deathwobble mean the same to me i guess. id say its probably more than a bumpsteer than a wobble though....maybe a little whobble around 80mph, but...i think thats probably expected.

 

Get the tires balanced,check the front end for play,
and check the caster angle. Dumbass.



If you want a smooth comfortable ride,buy a Caddy.

 

I'm sure that's exactly what he wanted....a smart ass reply.
The only dumbass question is the one a dumbass doesn't ask.
Alttile wobble at 80 mph is expexted with bias plies. Have them balanced by a qualified shop. I bet this is a big part of the problem.

 

you hurt my feelings!

haha. its all cool, yeah ill get the tires rebalanced, and check eveyrthing else out, dad owns a shop that can do all this, has an alignment setup, etc. (hey dad, ya readin this?) but my original question still hasnt been answered

that is, will an 11 inch pitman arm on a 36 pontiac box, be an issue. if not will something likethe above, work.

 

You will like the longer pitman arm. Make up a spare and try it. As for wobbles, you shouldnt have any, follow Unks advice. Also what tire pressure are you runnung? My Touring is 24# front 20# rear. At 30# front I would get "wobbles"

 

Good point. In a lightweight hot rod, a few psi will make a big difference. I run 20 in the front and 18 in the rear. With the new tires on the rear, I'm gonna have to do some experimenting. Glad you brought this point up Tman.
Thanks.

 

A longer pitman arm is going to quicken up the steering a bit, If its got bump steer than getting the drag link level should help you. But if its a wobble I'm going to suggest thet you have other problems.

 

24 up front.

not sure the rear.

im almost positive this is the only major problem, i guess ill give one of those alum. jobbers a try. the alum going to go well with the hardened steel drive gear or is just going to grind up? cuz that would SUCK going down the road. like, REAL bad .thats the only thing that makes me nervous about he alum ones .

 

I may have a longer pitman arm you can try.

Bumpster is when you hit a bump the car steers itself. In your case I would think it would steer to the left.

Deathwobble is when you hit a bump the front wheels go crazy and the only way to stop it is to come to a stop. Sometimes you can accelerate through it.

Lengthening the arm will make it steer harder sitting still.

Let me know if you want to try the longer arm. If so measure the shaft at the splines.
Clark

 

ah yes, i remember you were having deathwobble woes, how could i forget.

yes id like to try a longer arm, its not a death wobble , more of a bump steer.

is it an alum, or steel arm?

 

It might just be an optional delusion but the KPI looks off in that pic. That will cause nasty wobble problems.

 

KPI.....pfft now were using acronyms for things i probably wouldnt know if ya spelled em out?


where are those boobies!

 

The arms I have are old steel ones. How long is your pitman arm? I'll see what I have.
Clark

 

Is your steering gearbox centered and the pitman arm verticle when the wheels are pointed straight ahead ? Many guys make this mistake. I've re-done several like that and the difference was night and day.

 

Rob,

I would get those tires balanced - I think this may be your problem. I never did get them balanced!!

The pitman arm was vertical at the wheels straight forward point when it was setup. I was always going to go with the longer arm but alas I ran out of time before it went out to you.

Check the balance!!

 

Deathwobble is what is commonly known as "shackle-rock". It is primarily caused by a combination of worn kingpin bushings and misalignment in the front end. A small shimmy sets up harmonics in the front end, and the shimmy rapidly accelerates untill the car is actually swinging back and forth on the spring shackles.---a real pants shitting experience at anything above 20 miles an hour. The best cure for this malady is new kingpin bushings, 5 to 6 degrees of positive caster (top of kingpins leaning towards rear of car), a Panhard rod on the front axle that pivots off the frame on the drivers side and off the axle (or batwing or wishbone) on the passenger side. The Panhard rod will prevent violent pants shitting shackle rock, as it only lets the car frame and body move up and down with spring deflection, but prevents movement side to side. A good "help" for minor shimmy is a vibration damper, which is kind of like a long shock absorber that runs horizontally from the passenger spindle arm (it clamps onto the tie-rod end) over to the frame on the drivers side.
If you have any bump steer, (car hits railroad crossing, steering wheel violently jerks to one side or the other, making car want to change lanes), then that is a different issue.---A longer Pitman arm will only make it much worse---think about trying to pry up a rock with a lever---the longer the lever is, the easier it is to pry up the rock. Your longer Pitman arm will act like a longer leaver, and any forces transmitted to the drag link by the wheels wanting to bumpsteer will then have a much easier time jerking the steering wheel out of your hands, or even breaking your wrist.
Your steering box is positioned incorrectly in the car. It must be repositioned lower, so that when the wheels are pointed straight ahead, and the steering box is half way from lock to lock, the Pitman arm should point straight down, and the drag-link should be parallel to the ground.
Use a universal joint in the column so that when the steering box is moved farther down (vertically), the steering shaft won't be on a really steep angle like a 70's era T-bucket.

 

I'm guessing sumpin different. I dont see hardly any caster in that setup. That would cause the shivers at slow speed. As the car goes faster the gyro effect in the spinning wheels/ tires makes it harder to get to shaking...

 

Lets start this over again. 10 guys are shooting at different problems, lets address one issue at a time. Since you are a self professed expert on boobies you should know that when looking at too many boobies you lose focus. Please answer some questions regarding your steering. This will help determine if you need to change the pitman arm, change something else or stop at the ATM for more $1's.

1. Are you complaining about hard steering or lack of steering return when you make a corner?

2. At moderate to slow speed, when turning right or left, and your hand at 12 o'clock position on the wheel, how far to does the steering wheel have to be turned to the 3 or 9 position to make the turn?

3. At normal driving speed 30-55 mph, does the car dart side to side and require corrective action?

4. At normal driving speed 30-55mph, if you hit a bump, does the car dart side to side or require corrective action.

5. Has the front end alignment been checked, Toe in/out, caster, air pressure, tire balance, axle in square to the frame, worn componets?

The race car pitman arm that has been displayed has a specific diameter, tooth pitch and taper and may not match your steering sectorshaft. So before you go of and purchase one you will have to count the splines on your box and deternine the taper angle and diameter for correct fit.

You do have an issue with the pitman arm drag link angle as we talked about but I still am not sure if you are complaining about a driving issue or a hard steering issue.

I did see in the picture that potentially you have an incompatiblity problem when using 37/41 spindle on a 33-36 axle as the parts are designed different. This in it self can produce a hard steering problem.

Before any further input we will await yours.

 

Tires have too much pressure in the fronts.....Have someone turn the steering wheel while car is stopped-and watch to see if the axle shifts right or left under the car, while he is turning....if it moves much at all- it needs a Panhard bar.....

 

KPI King Pin Inclination (castor) sorry for confusing you

 

King Pin Inclination is viewed from the front.

Caster is viewed from the side.

 

Dick...37-41 spindles can't be used on 33-36 axle? Please explain. I thought this has been done since the early thirties when guys wanted to upgrade to hydraulic brakes.
Thanks,
Clark

 

THE KING PIN INCLINATION IS DIFFERENT BETWEEN THE A-36 SPINDLE THAN THE 37-UP SPINDLE.

WHEN INSTALLED ON A STOCK AXLE THIS CREATES AN OFFSET SCRUB ANGLE AND MAKES THE CAR HARD TO STEER. SORT OF LIKE FLYING AN AIRPLANE. HARD TO TURN AND IT DOES NOT RETURN WITHOUT ASSISTANCE.

NOW THIS IS SOMEWHAT REDUCED WHEN THIS APPLIED TO A STRECHED DROPPED AXLE AS THE KINS PIN INCLINATION IS SORT OF REBENT IN THE DROPPING PROCESS WHICH NARROWS THE SCRUB ANGLE. ONCE YOU HAVE EXPERIENCED THE STEERING DIFFERENCES YOU'LL UNDERSTAND WHAT I MEAN.

JUST BECAUSE SOMEBODY DID IT DOESNT MEAN IT IS CORRECT. YOU SAW MY BLACK COUPE, WELL 25 YRS AGO I THOUGHT THAT I'D TAKE THE EASY WAY AND JUST PUT ON 37 SPINDLES, TERRIBLE STEERING PUT THE 32'S BACK ON WITH BACKING PLATE AND BEARING SPACERS DRIVES LIKE NEW. NOTHING LIKE LEARNING THE HARD WAY.