Where to shim to fix rear toe in?

[thewaiverproject]

1971 240z

Hi i have a big rear toe in problem on my driver side.

I've read some threads about shimming to fix the problem, but I still don't get exactly where do i shim.

On the stock rear control arms, all the bushings run parallel to the wheel, so i don't logically understand how shimming them will adjust toe.

So could someone tell me exactly which bushing area to put spacers? I'm just not getting it. Also, will shimming the strut/camber plate via the inside trunk area affect toe as well?

 

 

Here is old alignment numbers: but i didn't drive it much after.

 

Front Left Front Right

-0.2degrees Camber 0.5degrees

3.8 degrees Caster 1.7degrees

2.2mm Toe 0.2mm

Rear Left Rear Right

-1.8degrees Camber -3.4degrees

6.5mm Toe -3.1mm

Car pulls to the right. thrust angle is pointed that way from the numbers.

I dont think it's a subframe problem, so I'm seeing if i can straighten the back 1st before i try the front.

Edited August 6, 2011 by thewaiverproject

[JMortensen]

Camber bushings, slot the uprights and move them to the right, "poor man's toe adjuster", adjustable control arms. Those are your options. There is nothing that can be shimmed to fix.

[palosfv3]

Front Left Front Right

-0.2degrees Camber 0.5degrees

3.8 degrees Caster 1.7degrees

2.2mm Toe 0.2mm

Rear Left Rear Right

-1.8degrees Camber -3.4degrees

6.5mm Toe -3.1mm

Car pulls to the right. thrust angle is pointed that way from the numbers.

I dont think it's a subframe problem, so I'm seeing if i can straighten the back 1st before i try the front.

 

 

Leave the back suspension alone until you fix the problem in the front . You need to go back to square one and check all suspension control point measurements . What I read from the numbers posted is a huge difference in the front caster . 3.8 lt and 1.7 rt . You have more than the preferred 1 degree difference between the two. I believe your problem lies here. I'm assuming this is a stock suspension which should be around 2.5 to 3.0 caster in front. More than likely you have something worn out ( t/c rod bushings )or bent ( lower control arm , damaged engine/suspenion cradle, bent t/c rod or bracket. or unrepaired structural damage ) on the right front lower suspension. Rear suspension alignment , especially toe in , will have minimal effect on front suspension conditions.

As far as your rear suspension I would suspect a weak rt rear spring as you also have a fairly large difference in camber in the rear . Since the factory rear suspension is non adjustable , you will find that this ride height issue can change toe .

One other issue to consider is the tires. If tires on this car have been driven for an extended time with these settings there is the possibility of the steel belts being distorted . This means that once you get all the suspension back in spec the tires could still cause a pulling condition .

[johnc]

Disassemble the rear suspension and check for bent parts. Also check the subframe to make sure its square. Those numbers indicate that something is bent or out of place. You need to find and fix that first before buying aftermarket parts to increase adjustability.

[jasper]

My 2 cents.

 

Toe does not cause a pull.

Only toe, and excessive camber wears tires.

Thrust angle will cause dog tracking, but not a pull.

.5 degrees of front camber difference can cause a pull.

Brand new tires, and or worn tires can cause a pull(front)(swap left to right to fix, and or confirm)

Excessive caster difference can cause issues. ( you have both camber, and caster issuses in front)

Fix what is broken/worn.

Shifting crossmembers/subframes can aid in evening up side to side differences.

Side to side equalization is you major concern, assuming close to spec.

 

If still out of spec,or for ease/accuracy of adjustment, use aftermarket eccentrics or

camber/caster plates, etc. This assumes no structural damage.

 

This approach works for me on a daily basis on todays cars.

Edited August 7, 2011 by jasper