Front end trouble - after installing new parts

[christiandk]

So I replaced ball joints, tie rods and shocks on my 76 912E.

I have just eyeballed the alignment until I csn take it to a shop.

Problem is when i go forward or backwards and steer to either side the right front wheel sort of skids/skips as if it is pointing in an entire different direction. Sounds nasty and I really domt want to drive the car at all like this.

Wheels look pretty parallel to me. Would a slight misalignment cause this?

Any idea whether to go toe inn or out or ideas to get in the ballpark without having to manufacture a fancy setup of strings or pipes?

Thanks,

Christian

[reddogmotrsprts]

Get it as parallel as you can and you can dial it in on the street if necessary; it's easy to feel toe.

I'd be more worried about the noise, but it's not clear what "nasty" sounds like. Can you describe it better? Where is it coming from and why? Check your work and see if you can get eyes on the suspension as it changes direction.

You can also try adjusting the toe dramatically in one direction or the other in order to see if it solves the noise problem. This is easy and harmless if you're not really driving the car.

[christiandk]

Thanks for the input reddog.

The noise is from the sort of skipping over the pavement, like it is being pushed or dragged in a not ideal direction for the rotation. Will try adjusting it a bit later, and give an update.

Fig 8 scrub is what I am having. Solution?

http://www.pelicanparts.com/techarticles/101_Projects_Porsche_911/60-Alignment/60-Alignment.htm

[Jcslocum]

Do you have 2 tape measures???

Just measure front and back of the center of each tire to center. Get about the same number and you wll in the ball park. It's really simple. You really only need 1 tape.....

[christiandk]

Thanks Jon,

Sorry, Im a bit slow. Do I mesure the center of the wheel up against front and back end of wheel arch?

Ahhh, found a youtube video.

[Jcslocum]

No, between the center of 1 tire to the center of the other tire. It can be any rib in the tire as long as you use the exact same position front and back. Once the distance is the same, you will have about zero toe.

You will need to LOCK the wheel in place so that when you move the tie rod adjustment, the tire moves and not the steering wheel. The lock on the column isn't always in the right place so I use a piece of rope (thin) thru the wheel and then out thru the door opening by the mirror and then slam the door on it to hold it in place.

http://www.ehow.com/video_2327639_measure-toe_in-wheel-alignment.html

[christiandk]

Gracias!

[RedCoupe]

I like to jack up each wheel in turn and spin the wheel holding a piece of chalk or a light colored marker to the center of the tire. This makes a center line that is easy to measure from on the front and back of each tire.

[targa44]

.... sort of what Redcoupe said, but how about jack up right side - turn the wheel right or left and spin.... any restrictions in full droop? Maybe you'll hear the noise.

also - does your car have front anti-roll bars?

[DRACO A5OG]

It may be your bearings are loose. Check those too.

[Jcslocum]

Christian, any result??

[Bob Kontak]

Originally Posted by DRACO A5OG

It may be your bearings are loose. Check those too.

Good thinking. Just grabbing wheels should be a quick check.

I am a little baffled by this one.

[Chuck.H]

There is an often overlooked alignment parameter that I was just reminded of in another thread on this board, and this is Steering Axis Inclination or SAI. This is the angle that the strut takes as it points down towards the ball joint.

I'm seriously out of my expertise here, but it seems for best results the strut needs to be pointing towards the center of the tire. When you lower our 911's, and then you either get a lot of negative camber, or the strut starts standing more vertically.

Just something to consider..

Chuck.H
'89 TurboLookTarga, 391k miles

[Flieger]

With most strut suspensions SAI is directly related to camber since the steering axis is the strut. Higher SAI with a positive scrub radius just adds steering weight and reduces the amount of negative camber when the wheels are steered.

Sounds to me like the poster has normal vehicle operation. Mine scrubs on U-turns. Don't think Porsche put in enough Ackermann for low-speed tight turns. But in some cases you actually want reverse Ackermann so it's always a compromise.

[Chuck.H]

SAI is related to camber, BUT if you lower the car the SAI will have to change to achieve the same camber setting, because as you lower the car the A-arm is swinging upward, adding camber all on it's own.

Mine scrubs a little on low speed tight turns also for the record.

Chuck.H
'89 TurboLookTarga, 391k miles

[Flieger]

Originally Posted by Chuck.H

SAI is related to camber, BUT if you lower the car the SAI will have to change to achieve the same camber setting, because as you lower the car the A-arm is swinging upward, adding camber all on it's own.

Mine scrubs a little on low speed tight turns also for the record.

Chuck.H
'89 TurboLookTarga, 391k miles

You'll have to correct the SAI but if you want to end up with the same camber then you'll also have the same SAI. Only if you run more camber would you have greater SAI.