Why does my 914 change track?, at any bump in even slight bends Options

[larss]

haha,
Its not bump steer..

If anything, its to high in my opinion, but that is not your problem right now.

Do you have any play in the steering wheel at rest?
Any clicks when you shake it back and forth?
... ... ...
rich

Thanks Rich!

There is no significant play but a "soft" click can be noticed when shaking it around center, first i thougt it was one of the U-joints under dash but changing it did'nt make it better.


/Lars S

[mepstein]

(IMG:style_emoticons/default/agree.gif) looks high in the front

[FourBlades]

This is what low looks like.

Look at where the wheels are at the top of the fender arch.

This car has no bump steer kit and handles perfectly.



I admit I love this picture of my car and was just looking for an excuse to post it again. Does that make me sick person? (IMG:style_emoticons/default/confused24.gif)

It does? Ok, so what! (IMG:style_emoticons/default/biggrin.gif)

By the way, that is a really nice looking 914 you have...

John

[messix]

isn't that kinda like what mcmark had when he found the steering "isolator" between the column and the rack about to fall apart ???

[r_towle]

haha,
Its not bump steer..

If anything, its to high in my opinion, but that is not your problem right now.

Do you have any play in the steering wheel at rest?
Any clicks when you shake it back and forth?
... ... ...
rich

Thanks Rich!

There is no significant play but a "soft" click can be noticed when shaking it around center, first i thougt it was one of the U-joints under dash but changing it did'nt make it better.


/Lars S

Have you checked the tie rod ends and bearings?
If yes, it's the rack.

It's an old age issue that the rack gets worn right in the middle where you center the wheel and that creates a click, and the car will wander.

Did you say you already replaced the tie rods with turbo tie rods?

[Spoke]

Thanks everyone!

I have made several toe-in checks on different floors with my home alignment tool; Always the same result the toe in is about 3/8".

This seems like it's quite toed in. When I set my 914 and 911, I set it to 1/8". This is the difference between the front of the wheel and the back of the wheel, about 25" apart.

I don't have the 914 repair manual with me but I think the toe in is 20 min +/-10 min.

I got the above numbers from this article:

Early Porsche Alignment

According to Pelican's tech article, this would be just about 1/8".

Pelican Alignment Adjustment

3/8" would equate to 53min or 2 1/2 times more toe than specified.

[r_towle]

(IMG:style_emoticons/default/agree.gif)

Total toe in should be 1/8 of an inch at the front and zero in the rear.
Camber should match side to side.

[larss]

Thanks everyoune for your input it has been a great help to me!

By locking the lowest part of the steering shaft I can see that there is a minor play in the lower U-joint (the one just above the pedal cluster).
Are theese joints ment to be 100% free of play?

/Lars S

[Porsche930dude]

i agree way too much toe. I measure my alignments at home by simply hooking a measuring tape on a uniform part of the tire tread and measure it as high up as you can front and back. that has proven to be quite accurate for me. way better than driving over a piece of paper anyway (IMG:style_emoticons/default/laugh.gif)

[r_towle]

Thanks everyoune for your input it has been a great help to me!

By locking the lowest part of the steering shaft I can see that there is a minor play in the lower U-joint (the one just above the pedal cluster).
Are theese joints ment to be 100% free of play?

/Lars S

They all are a bit loose.
I would suggest you align the car.

Look around here for the how to using strings, it is simple and very accurate.
Get the toe correct, especially if one side is way off.

You may be off on your camber and toe on one side of the car, and that will make it feel like crap.

Learn to do your alignment, or go to sears, get an alignment and some coffee while you wait.

All the wandering and wiggles will stop bothering you if you can stay in a straight line again.

You mentioned above that one side is way off on camber, it may also be way off on alignment. Did you possibly hit a curb or ditch with that side?

Rich

[larss]

...
You mentioned above that one side is way off on camber, it may also be way off on alignment. Did you possibly hit a curb or ditch with that side?

Rich

Thanks everyone!

My camber is now triple checked OK, just a few mm on each side, the earlier was wrong due to uneven floor (IMG:style_emoticons/default/sad.gif) .

I have now set toe in to 1/8 and what a difference!Havn'tdriven so much yet but 1st impression is success.


I follow the Pelican article, have two angled sheet metal pieces with same widthasthetires (24"), the instructions are

Take the difference between the measurements of the front and rear of the tires then divide by 2 and that is the toe in/out per wheel in inches.

Spoke wrote above that
"...set it to 1/8". This is the difference between the front of the wheel and the back of the wheel, about 25" apart."

Which one is correct, Pelicans say to divede the diff by 2 but the other not...?
Edit:
Oh, yes Spoke refers to one wheel at a time but Pelican is about both wheels and the measurement has then to be divided by 2, right?

/Lars S

[ChrisFoley]

Which one is correct, Pelicans say to divede the diff by 2 but the other not...?
Edit:
Oh, yes Spoke refers to one wheel at a time but Pelican is about both wheels and the measurement has then to be divided by 2, right?

/Lars S

Total toe-in is the sum of the toe-in of both wheels.
About 1/16" total toe-in (1/32" per side) is sufficient if turbo tie rods have been installed. I measure at the wheel rim, not on the tire.

[r_towle]

(IMG:style_emoticons/default/agree.gif)

Dont use the tire.

I am not a fan of just using an angle piece because you could potentially put all the toe on one wheel and not know it.
Using strings (or a machine) gets you using the centerline of the car, and therefore adjusting BOTH sides identical.

Rich

[larss]

I use angle sheet metal pieces but I dont use the tire but the rim for reference. I put the sheet metal at equal distance (about 1") from the rims most forward and most backward point and then do the measurements from the forward and back edges of the 24" wide sheet metal.
Of course using a machine is the best.


/Lars S

[larss]

Found that the rack has a play in its outer right end, sideways and up and down, not in/out...putting this in a new tread.


/Lars S

[r_towle]

I use angle sheet metal pieces but I dont use the tire but the rim for reference. I put the sheet metal at equal distance (about 1") from the rims most forward and most backward point and then do the measurements from the forward and back edges of the 24" wide sheet metal.
Of course using a machine is the best.


/Lars S

Without using the centerline of the car, like a machine would do, or like running strings from front to back, you cannot know you are doing the front end correctly.

For a quick adjustment at a track event, it works.
For a baseline setup, it does not.

Get four jack stands or milk crates.
Run two strings parallel to each other front to back on the car.
String height needs to be at the centerline of the wheel.

Front and rear track widths are different, but you need the string to be the same distance on both sides in the front, and then again in the rear.

[andys]

For at the track: Two people, duct tape, a pen, a measuring tape, and a reasonably level area.
1. Measure the lowest point of the undercarrage from the ground up at the rear of the front tire such that the tape measure will span from one tire to the other without obstruction. The lowest point on a 914 is at the rear. Some cars have the lowest point at the front of the tire, but I've found that is rare.
2. Wipe the rear part of the tires clean of dirt at the height in #1. Place a piece of duct tape 2 or so inches long and mark a horizontal line with your pen at the height measured in #1. Do both front tires. It's not important where the duct tape is placed right to left.
3. Make a vertical pen line intersecting the horizontal line; anywhere convenient is fine, both sides. You now have two crosshairs to work with. I like to use a ball point pen for the nice crisp lines.
4. Measure the distance at the rear of the tires at the crosshairs. For accuracy, it's best that person A align the tape measure at the 1" line, rather than at the hook. Person B should record the distance at the other side.
5. Roll the car forward until the crosshairs are at the front of the tires at exactly the same height as they were at the rear. Measure and record.
6. Make your adjustment and roll the car forward until the crosshairs are again at the rear. Measure, then roll the car forward and measure again to determine correction. Only roll the car forward for each subsequent measurement to keep the suspension and steering loaded in the same direction. If you're short on room, you can roll the car back , but past the starting point, then forward to start the process again. Oh, make sure the steering wheel is pointing straight....on race cars I like to clamp the steering wheel to insure it doesn't move.

I've used this method for many years, and the degree of accuracy ia way better that stringing, IMO. The only thing to compensate for, is that these measurements are below wheel center, so the toe values should be slightly less.

Andys