Wheel Alignment

[Lewis]

I have a 1971 Datsun 240 Z. I have just installed new tires and had the alignment checked on the car. The mechanic says that the front end is out of alignment and that seems to be repairable. The problem seems that the rear end is also out of alignment. There does not appear to be any way to adjust the rear wheels. I suspect that this was not an issue in the 70's but I am not sure about that. Does anyone know of any way to correct the rear end alignment? Thanks for any help with this.

[jmortensen]

The only real adjustment on the Z in the front is toe. There is no camber adjustment and depending on the condition of your T/C bushings, you might be able to shim a bit of caster too, but its very limited. The rear, as you said, is totally fixed from the factory.

You can make everything adjustable, but it takes varying degrees of modification. Probably the easiest way to make the rear adjustable is via camber bushings.

http://www.thezstore.com/page/TZS/PROD/PSDC07/23-4171

[doradox]

Before you run out and buy camber bushings there is a difference between out of alignment according to the factory specs and bad alignment. If you could post your numbers we can advise you on whether or not they are worrisome. I always prefer a little more negative camber than the specs call for so my Zs have always been "out of alignment".

Steve

[jfa.series1]

If your mechanic is reporting a camber issue, that might mean worn shocks or sagging springs. If it is a toe in/out issue, its possible you have worn bushings on the lower control arm (also called transverse link) or a bent LCA. Like Steve recommended, share some numbers and you can get better insight.

Jim

[olzed]

A simple way to check the four wheels for toe in or out. Run a strong string around the four wheels, making sure the steering is straight ahead of course. I used to do this to align the wheels on motorbikes, and have found it good on my 240. Just tie off one end to one of the bumper bars or whatever and walk around the car with the string, keep it tight and in line on all the wheels, and tie off the other end on something suitable. You can see at a glance if anything is wrong.

[Lewis]

Thanks for the info. Below are the readings as I got them from the shop.

Left front:

Camber .0 degrees

Caster 3.1 degrees

Toe .99 degrees

Right front

Camber .5 degrees

Caster 3.5 degrees

Toe .82 degrees

Left rear

Camber -.8 degrees

Toe.25 degrees

Right rear

Camber-.5 degrees

Toe .23 degrees

Any help you can give is appreciated.

Lewis

[jmortensen]

That actually is the single BEST alignment printout for an unmodified Z car I think I've ever seen. Fix the front toe (you can do this with a partner and a tape measure) and drive it.

Edited October 15, 2010 by jmortensen

[gnosez]

I strongly second Jon's assessment and his suggestion....

[ajmcforester]

I'd agree without pulling out the manual it looks to be close to aloud tolerances. Except the front toe. That is not hard to fix.

We should also ask are you using stock rims, or have you gone up a size? What tire demention are you using?

On my last Z the camber was OK with the stock tire size. When I went to a one inch larger rim it made a larger flat surface, and I started to get a slight uneven wear. To fix that I installed the camber kit. The wear was livable if I rotated the tires but they were directional tires. So the like a 185/70R14 you should be OK

[240zdave]

I am dealing with this same issue on my '71 right now. I've got 3/8" toe in on the rear wheels. The PO had installed camber bushings on the rear A-arms, but only the ones toward the front. With the front bushings adjusted all the way out, I still have 3/8" of toe-in.

I talked to John Williams (Z-car shop in Sugar Hill, GA, just outside of Atlanta), and he told me that most likely one or both of the rear A-arms are bent out at the small end. The way to tell is to look at a couple of holes adjacent to the small end, next to where the spindle pins go through. If the holes are not round, but are elongated or egg-shaped, the A-arm is bent (see attached diagram).

He told me it is difficult to find an A-arm that is not bent. If you can't, the best you can do is to install the camber bushings on both ends of the large end, and take as much of the toe out as you can. He told me that the 240Z came from the factory with 0 degrees of toe-in or out, meaning that the rear wheels should be parallel with each other.

deformed a-arm3.bmp

[jmortensen]

The toe in on the OP's car is not bad at all, and it's so even I'd have a tough time buying that it is a result of a bent arm. Much more likely to be bushings that are worn, but the .25 degree number is totally driveable. I used to add 3/16" total toe in to my car when I was autoxing because it makes the car more stable on the brakes and also when you get a little sideways. With a 225/50/15 tire, the toe in degrees to achieve 3/16" is .43 degrees. With that same size tire, the actual toe of the OP's car in is .050" total. Very very driveable.

Inches to angle toe conversion tool:

http://forums.hybridz.org/index.php/topic/60450-toe-in-converter/

[Lewis]

Thanks for all the input on this. I will proceed with this.