Front end popping/settling noise when car is parked

GreetingS FABO!

Working on memory here...I recently did the disc swap on my 65 Barracuda w/new bushings/balljoints.

No front alignment yet.
Alignment is "roughed" in.

But after driving car and upon parking, the vehicle sorta "pops" when sitting still as if..[settling] is occuring..?

Upon finishing install of parts and assembly, i did the push up & down on FE to help settle in.....before torquing to specs.

I read in a thread somewhere but cannot find it to recheck myself.

Whats happening here?

Although it doesnt seem as frequent as when i initially completed task.

Also, what alignement spec are recommended for street cruising?

Thanks FABO!

If the upper and lower control arm bushings are not preloaded at ride height, which sounds like you have covered, and your alignment is roughed in, I would say your toe is way off, and when you drive it, the tire scrubbing is pulling hard on the tires, either in or out, and it's jacking the suspension, and changing your camber. The tires are being pulled away from where they naturally want to be because they aren't pointing forward when you drive the car. It get exaggerated because as the tires pull away from the centerline of the car, they pull on everything, changing camber, and that changes toe even more. Turn the steering wheel back and forth a few times, and roll the car forwards and back a few feet to get as much preload off the suspension. Measure toe, then measure camber, which you can do by just holding a carpenter's square next to the tire, and measuring the difference from it to the rim on the top, and bottom. The same measurement top and bottom is obviously 0° camber. With a 15" wheel, if the top is leaning in by 1/8", you have 1/2° camber. You can extrapolate that--1/16"=1/4° and 1/4"=1°. I set my cars at 1/16" toe in, as much caster as I can get, which is the front excentric out all the way and the rear all the way in, then turn whichever eccentric I have to so the camber is 1/2° negative. Roll the car fore and aft several feet and check to see if the settings changed. Camber adjustments affect toe. You need the toe close to zero so you don't have that preload when you're settling the suspension, but it has to be the last adjustment you finalize. I don't care what my caster setting actually is because I can't get as much as I would want. If I had to give a number, I'd say 4° positive. I set it to get as much as I can, but being the same side to side is what you really need. If you have the fancy gauges, you turn each wheel 20° to one side, then the other, but you can just turn the steering wheel to one side, say one complete turn of the wheel, check the camber with the carpenter's square noting how much the tire tilts in at top, and record that number for both wheels. You don't need an angle, just the distance in inches. Turn the wheel back to center, and continue so it's turned the same amount in that direction as the previous one. Compare how much the measurements change. The more caster you have, the more they will change. I've never had a problem with cross caster. I've always done my own alignments this way, from 40 year old worn out crap, to rebuilt front ends, to 24 hour endurance road course racecars. Any questions?

Urethane or rubber bushings?

I believe rubber...I acquired the parts a few years ago..[memory]..they are black in color if that makes any difference. I'll see if i can find the receipt.

It's the height of the steering arm that makes a difference in the caster setting, I agree that I want as much positive caster as possible but if it changes the height if the steering arm to much you get to much bump steer and if you are drag racing it it will cause the car to be all over the track or turn under launch.

What are you calling the steering arm? Are you referring to what the outer tie rod end bolts to, which is part of the lower ball joint on our cars, the pitman arm, or something else?

It could be just the exhaust cooling down and shrinking, as they can make all kinds of clicks and pops.
Seriously doubt it's actually the car settling.

The steering arm is the part that bolts to the spindle or on a mopar is part of the lower ball joint.

brian6pac said:

The steering arm is the part that bolts to the spindle or on a mopar is part of the lower ball joint.

Click to expand...

How does that affect caster? I understand the bump steer, but the upper control arm doesn't affect that. Could you elaborate? Are you referring to the effect of the anti dive angle of the upper control arm as it compresses?

It doesn't effect caster, caster effects the height of the steering arm that effects bump steer.
That is what I said. As the caster goes more positive the steering arm goes down. That's why if you read the factory manuals on alignment it says to set your caster per the height of the vehicle. I'm not real good drawing with this program but you get the picture.

I see now. Thanks. If one is serious about this, they'll be zeroing their bump steer anyways. My last racecar had 1/4" of toe change per inch of travel each side. The car actually handled fine until I hit the brakes hard into turns. Do you know how to zero it out?

My 64 barracuda had 0 bump steer from the bottom to about 3/4 travel up, then toed in hard so I had to limit the travel but you didn't have to hold the wheel that's how straight it went. When it comes to corners that is your toe out in turns and that also has to do with your steering arms. Your 1/4" per 1" of travel is a lot, way off but if it is real stiff you don't have much travel so 0 bump steer should be easy. Sense I'm not sure exactly what the braking in the corner problem was I really can't comment but there are a lot of books out there on the subject. Could just be a brake balance problem.

The front drops when you hit the brakes, so 1" drop in front, with 1/4" toe out each wheel, gives 1/2" toe out per inch of travel. I've gotten the car up to 156mph at Pacific Raceway's road course, so I'm hitting the brakes pretty hard before that U-turn. I had to be done braking by the time I wanted to turn. If I had to hit the brakes harder into the turn, it pulled into the turn hard, and pushed back out when I let off. The tires weren't sliding, the steering wheel wasn't pulling, and it all went away when I adjusted it to less than .010" per inch of travel.

Eestatic, how's the car?

When you turn the wheels it toes out that is designed in, and if you set the toe say 1/4" out when it is straight then it toes out more in turns. So if you have to much toe out in a hard turn it will tend to dive in. it's easy to see if you draw 2 circles and your car with the wheels turned smaller circle on the inside wheels and a bigger circles on the out side wheels, now the front wheels should be lined up on the circles that toe out is going to make the car fastest in the corner with out scrubbing the tires.

No. With the tire pointing forward, as I jack the wheel up, you could see it turn outward, so as it moved strait up and down, it would point left and right by 1/4" for every inch up and down it would move.

Right I got that, That's because your steering arms are to low, if your steering arms were higher it would be less or it would toe in, lets go to extreme's unbolt your outer tie rod from your steering arm and hold it straight out and drop it straight down. Now if your steering arm was hooked to it it would be toed out a lot. the further down it goes the more it toes out. now if you start with the steering arm 2" above the center link as it drops down it will toe in. are you getting the picture. Both control arm arcs also play a part in the bump steer. But first you have to understand the front end geometry and you can fix it the way you want.

I already fixed it.

Do you know how anti-dive works? I've never been able to figure that one out, how the pivot angle of the upper control arm reduces dive, and how the ball joint moving back under jounce doesn't cause strange handling behavior. Why does Hotchkis think our cars have too much anti-dive? Is that because it's not needed when higher spring rates are used? On my racecar, the old school way of prepping it was to increase anti-dive. Now, the consensus is to keep it stock, which is what I did.

Good info. I'll need to do suspension setup soon enough..... I hope. $$$$

I had something similar and had to put a couple more tightening turns on the strut rod on one side. went away after that.