Front torsion bar install question

BGCarrera32 · 01-25-2003, 07:20 PM

Getting ready to install my 21mm front torsion bars on my '84 Carrera.

I have installed poly bushings and custom fit them, so basically envison my A-arm as moving freely about its swing radius, it is currently seperated from the strut at the ball joint.

I have the new t-bar slipped in, but am unsure where to positon the A-arm in relation to the bottom of the strut before I slip on the adjusting lever and jack the ball joint up into the strut.

For instance, I let the A-arm hang about 75 degrees from the bottom of the car, placed a floor jack under the ball joint end, began to jack the arm up towards the strut, and lifted the whole car off the ground. Any thought as to what I should be doing, or is this pretty much a trial and error deal? Looking for a final ride height of around 24.5", ground to fender lip.

Thanks!
BG

KTL · 01-25-2003, 07:29 PM

You're doing it the way I did it.

I figured with the new bars that the car would not "compress" the torsion bars much. So to start I just jacked up the control arm (without the torsion bar installed) to I think an inch more than desired ride height.

It only took a few adjustments of my initial guess to get the end caps in the middle of the adjustment range while at the desired ride height.

Hope this helps a bit.

BGCarrera32 · 01-25-2003, 07:31 PM

Yeah, you're answer makes some sense, I guess I'm thinking I'll bring the ball joint up within an inch or two of the bottom of the strut, jack up and go from there. Sound reasonable?

KTL · 01-25-2003, 07:38 PM

Why don't you have the ball joint and strut connected?

The most important part is to have the torsion bar removed.

If you start jacking up the arm with the bar in there, you'll be preloading the bar too much.

My guess was based on how much I thought the bar would be loaded by the weight of the car. I started off with a couple inches and then I think I ended up at around an inch. Or was it the other way around? I can't recall. My bars were 22's by the way.

I'm sure someone like Wil Ferch has a math method of doing this, but I never bothered to calculate the math (I could you know......... really....... no REALLY

).

BGCarrera32 · 01-25-2003, 07:48 PM

Ah ha. I'm having a brain fart, that's why I don't have the ball joint connected to the strut. I had this whole thing apart, and then read page 162 of Wayne's 911 projects book where he says...

"When fitting the torsion bar back into the car, make sure that the suspension A-arm is hanging downward as far as possible."

But of course for the topic of just replacing the bars, he doesn't have the ball joint-strut seperated. My mistake....

Thanks
BG

89911 · 01-26-2003, 05:41 AM

With a stiffer bar, the travel of the a arm is less and the tension greater. If you let the a arms hang down and set the end caps withing this range, you will most likely have too high of a ride height. When I reinstalled my 22mm bars up front after changing a arm bushings, I had to jack up the end of the a arm and slightly preload on both sides to remove tension on the end cap and the adjustment screw. After replacing the bushings, I reversed the process and the height was were it needed with the adjustment screw in a neutral position.