LCA pivot pin Torque Time

[HeavyFuel]

I can't quite figure this one out, but a few of you fellas probably have.

Known: The LCA pivot pin is supposed to be final torqued AFTER the front suspension is set to ride height.

Unknown:  Why is this important, if the pin is a pivot point for the LCA?  Obviously the position of the LCA changes as the car ambles down the road and the suspension loads up and unloads.  Why can't the pin be torqued down with the car on jackstands, for instance, with the suspension unloaded?  Or maybe the LCA doesn't actually pivot on the pin.   

Or does it have more to do with the position of the adjusting blade inside the LCA during the torque down? (not the actual position of the LCA, loaded or unloaded)

I can't muster the will to figure this one out right now.......I just spent 3 hours on my back adjusting the ride height.....with no front wheels on....it wasn't fun.

Anybody care to clear this up?

[HPP]

Because when you torque it down, you lock the pivot bushing into that location. If that location is not within the range of normal ride height and normal suspension travel, then it will tear the bushing to get it to ride height once you put all the weight on it, which results in a bad bushing immediatly after you replace it.

[HeavyFuel]

Hmmmm.  That makes sense.


(Thinking some more...... )


I wonder how the urethane bushings get by without crumbling?  I would think that they have a lot less range of motion than the OEM rubber stuff.

[HPP]

Actually, urethane has a greater range of motion because they can spin within the shells. Rubber is molded to the inner and outter shells and exceding its elastic range is what causes problems. However, the downside to the urethane is that if you get grit in there, this motion can slowly grind them away while rubber is jsut flexing back and forth.

[flyinlow]

I got to do one of my LCA bushings again about a year after I did the front end on my 73. I suspect that I had the bolt too tight in the fully extended position and when I did the final torquing with weight on the wheels the bushing was under a bind already.    We just did my sons "70 and I made sure the nuts where lose enough that the bushings and bolts moved with LCA movment, until the final torque with the car on its wheels.  Still learning after all these years.

I made two strongly braced boxes out of 3/4 plywood  and 2x10s to support the back of the car and put the front on some ramps. I have a two post lift and lowered the car on to the 10 inch tall supports giving me enough room to set the ride height and torque the LCA pin nuts. This is also good for checking pinion angles.   

[HeavyFuel]

I got to do one of my LCA bushings again about a year after I did the front end on my 73. I suspect that I had the bolt too tight in the fully extended position and when I did the final torquing with weight on the wheels the bushing was under a bind already.    We just did my sons "70 and I made sure the nuts where lose enough that the bushings and bolts moved with LCA movment, until the final torque with the car on its wheels.  Still learning after all these years.

I made two strongly braced boxes out of 3/4 plywood  and 2x10s to support the back of the car and put the front on some ramps. I have a two post lift and lowered the car on to the 10 inch tall supports giving me enough room to set the ride height and torque the LCA pin nuts. This is also good for checking pinion angles.   

Good tips...thanks.

So....in order to prevent any accidental pre-binding condition, a guy should:
1.  set ride height
2.  loosen pivot pin nuts to release any prebind in the bushings
3.  tighten nuts to torque specs

Sound right?