Steering rack shims?

[Nadine UK GTS]

I am just bolting my steering rack back on to my '97 coupes new front frame section, and wondering what to do about the shims? They are unequal shims, should I put them back in as before, although they will not be correct set up for the new frame, I don't know how / and probably not possible to align the steering rack height as per factory build.

 

[Viper Wizard]

Hi Nadine,
I glad to hear you coming along with your Viper!!

I would put the shims back as they where[they are part of the Toe Pattern Ajustment] you are going to have to do a full aliment on your baby when you get finished. When you do the aliment and you need more or different shims, here are the part #'s for them.

#4708475 0.5mm
#4708070 1.0mm
#4708068 1.5mm
#4708069 3.0mm

Speedy recovery!

 

[Nadine UK GTS]

Thanks for the info, a help and much appreciated.

"Speedy recovery"...that day won't come soon enough when the snake and I get out of the garage. Can't wait! Thanks.

 

[GTS Dean]

Nadine,

First - make sure the wheel alignment is reasonably close to spec because the caster angle can have a major effect on toe pattern. When you bump steer the car, leave the shocks off or let the lower ends dangle vertically through the wishbones. Get yourself some 1" wood blocks to slide in and out. These can either go under the jack points at the front, or under the tires while holding the frame level.

Slightly loosen the alignment cam and upper A-frame nuts. This will reduce the sticktion in the suspension links. Measure the toe change at 5 points: curb, +/- 1" and +/- 2" wheel travel. Check against the shop manual chart, shim, then recheck until you are within tolerance. This is a relatively easy exercise when the fascia, radiator, etc., are off the car.

Best of luck,

 

[GTS Dean]

Jerry,

To establish the "Zero Point" all you need is the correct height between the frame and the ground, or the wheel lips @BDC and the frame. The car's loaded height is a fixed baseline relationship that is relative to these hard points. The only time you need the suspension loaded is to torque the shock eye and A-arm pivot bushings.

 

[Nadine UK GTS]

Thanks Jerry and Dean for the valuable advice.

Will be glad when I finally have my front suspension set up, I've been pressing no end of bushes in and out of the A-arms (Delrins) as I had trouble with small fractures appearing in the A-arms, and had to replace, seems once the arms have any kind of stress to them they weaken and crack up.

 

[Jerry Scott[CO]]

I would think that you would want all of the normal weight on the frame, including the radiator with water and the full fascia with all parts, before trying to set the bump steer. Otherwise the steering rack will be too low for the final setting, due to the spring compression from these added components. I may be wrong but, it seems to me that bump steer has to be set with the car's full weight on the suspension springs.