Installing/adjusting front torsion bars

[Jprather]

I am servicing my front beam and have a question about the torsion bar settings. After removing the torsion arms From the beam I noticed that the upper torsion bars on one side extend further than the other by about 1/8th inch. Is it possible to loosen the center lock nut on the upper beam and shift them so they are the same distance?

I have a 1968 ball joint stock beam. No adjusters.

I am concerned that having more bar one one side will cause issues when I try to set camber.

This is my first time working on the front beam. Thanks

[FJCamper]

Hi,

1/8" inch isn't going to make any springing difference, but you can loosen the center grub screw and try to get them equal.

You may find on retightening the center screw the stacked torsion leafs move right back into their old position.

If I were doing this, I'd loosen both top and bottom center screws, slide the trailing arms all the way in on both side -- emphasis on all the way -- and then tighten the screws.

On reassembly, get all the grub screws tight, especially on the trailing arms. That is all that is keeping your front end together.

FJC

[Jprather]

Thanks FJC for the response and all your other posts. I have learned a lot about suspension tuning reading your work. The book says to torq the grub screws anywhere between 29 to 36lbs. That doesn't seem like much. I set mine at 36. Is that sufficient in your opinion?

[Marc]

Short answer, yes.

Keep in mind that the original torque specs were in SI units, and "translated" for the US.
29 to 36 lb-ft sounds much fussier than 4 to 5 mkg.
Generally, the spec is based upon being enough to do the job without placing undue stress on the fastener threads - as in the case of the locknut, which can take more without stripping...but 36 should be adequate.
The SCREW is another situation - as it tightens into the spring stack, its tapered nose spreads the leaves apart and puts stresses into them which can lead to failure if excessive...here's a case where you shouldn't exceed the maximum spec even though the threads could handle it.

[FJCamper]

Hi,

I have had the lower center nut and screw loosen and fall out of an adjustable Puma axle at Road Atlanta. After that, we overtightened.

Being cautious, we recheck tightness after every race.


FJC

[Chris V]

Some adjustable beams use two jam-nuts per adjuster, instead of the single OEM anchor but.