1970 Cadillac RWD tie strut installation, front suspension restore

[Scot Minesinger]

Restoring the front suspension on my 1970 Cadillac Sedan DeVille.  The new ball joints, bushings, and springs are installed.  The steering knuckle is reattached to steering tie rod.  Now it is time to install the tie rod struts with replacement bushings.  I was careful to mark the back lock nut on the strut before removing it for powder coating, and the nut is reinstalled to the correct position.  The shop manual even for new tie strut bushings instructs:

1.  Install concave side of large metal washer towards rear lock nut, slip rear bushing on and insert tie rod thru frame front opening.
2.  Loosely bolt tie rod to lower control arm, insert front bushing and install lock nut on front loose.
3.  Lower car and tighten lower control arm to tie rod bolts and nuts, tighten front lock nut on tie rod.

The problem with these instructions is that the rear bushing requires it to be compressed for it to be lined up with the lower control arm holes so that the 7/16" fine thread bolts can be inserted thru both tie rod and lower control arm.  The only way to do this is to install front lock nut which will compress the rear bushing.  There is a metal stop that is a sleeve that rests against the two large washers on tie rod so that the rubber bushings cannot be over compressed.

So I compressed the rear bushing with lock nut in front until mechanical stop was reached.  Problem is the lower control arm and holes are off by about a quarter inch (holes in tie strut are too far back).  My question is which way to go on fixing this? I can force the lower control arm back about a 1/4" thereby putting a stress on new lower rear control arm bushing.  I can adjust lock nuts so that tie strut is not same as when I took it off the car and caster could be way off.  Or is there another way to go?  Keep in mind everything has been replaced; upper and lower ball joints, upper and lower control arm bushings -all new.  The length of the upper control arm bushings are made in such a way that the upper control arm could be installed a range of about 1/4" running front to back, so the one mechanic could have installed it 1/4" more forward than another and there are no instructions on this.  From an engineering perspective the more durable installation is as forward as possible, which I did do.

I'm leaning toward putting car on ground, adjusting lock nuts on tie strut so that compression of bushings results in line up of tie strut and lower control arm bolt holes.  Was hoping to drive to alignment shop, rather than flatbed it, but if needed will flatbed it.  I have been carefully reading the shop manual this whole process and this is my first suspension restore.     

Thanks for helping a novice.

[The Tassie Devil(le)]

Boy, what a question.

Personally, in these instances, I have wound the rear nut on the Tie Bar rearward so that there is no pressure on the front bushings, and that the two 7/16" bolts can be inserted into the lower control arm, nutted up, but not tightened.

Then put the car on the ground, and then tighten up the front and rear Tie Bar nuts to centralise the bushing on the bar and then the two 7/16" bolts.

This way the arms are in their near to proper place when tight.

Bruce. 

[dadscad]

When removing and installing any front end part(s), particularly with all at one time replacement, nothing will be in the position it was prior to installation when reinstalled. If you left the rear adjusting nut on the lower control arm strut in is original position, you would need to pry the lower control arm forward or aft to get the attachment bolts to go through the strut and lower control arm. The strut adjusts the caster of the wheel by pulling or pushing the lower control arm end to  or from the front of the car. Your new lower control arm inner bushings will be flexed some now, or when the alignment is done. By moving the lower control arm to align the attaching holes without moving the adjusting nut you will have the caster in the relative adjustment prior to removal, it will not be correct nor will the camber or toe in.

The most important thing, when tightening the inner lower, inner upper control arm bushing pivots, have the weight of the car on the suspension. After the inner pivots are tight, then tighten the lower control arm strut bushings before you tighten the strut to lower control arm bolts. The suspension needs to be supporting the weight of the car when suspension parts are tightened.

[Scot Minesinger]

Thanks for the replies, confirms what I was thinking and it is so much nicer to proceed with confidence.