Should I replace the torsion bars?

[gcdsn76]

I need to do the control arm bushings and tie rods on my 67 Charger.  What if any benefit will I get by installing new torsion bars? Do they wear out? Any recommendations on bar diameter? Also, how hard is it to change out the power steering chuck?

[ODZKing]

Torsion bars are either good or not. I don't believe they get weak But that is my  .  I am sure some will disagree. 

[myk]

They're formed pieces of steel that carry the weight of the front end, and have been doing so for almost 50 years.  I would change them just because of that, and go with as large of a torsion bar as you can get.  What size do you have now? 

[Mike DC]

  
They lose their height, like all springs over time.   You can re-adjust the height back to where it should be with the lower control arm adjuster bolt.  But in the long run it's not a bad idea to spend a few hundred bucks right now and replace them while you have the whole thing apart.  

The original spring rates could use some help.  I don't necessarily agree to get the stiffest thing you can find (some of us actually want a comfy car) but if the car was being built today it would have gotten stiffer T-bars than the factory gave it 50 years ago.  Especially big-block cars.  The factory rates were 0.88" to 0.92" range for B-bodies.  The aftermarket makes 0.94", 0.96", 1.00", etc.  (The stiffness ramps up exponentially as the bars get larger, like with a sway bar.  A 2" T-bar would be WAY more than twice the stiffness of a 1" bar.) 


Also, be careful not to nick/scratch the surface of the T-bars any more than necessary during removal/install, be it new T-bars or old ones.  Small nicks can grow into cracks as the bar gets flexed and the bars can eventually break.  It's not a big deal (these cars survived with the bars exposed to gravel & road debris all these years, didn't they?) but it's a reason not to use the wrong clamping tools or carelessly handle the bars.  

[ws23rt]

I agree with all that Mike DC has said.^^

My addition is that the quality of the spring steel of the torsion bars is the important value. An old bar that has relaxed some is still of the same metal quality it was made with.  These things don't go bad unless they are scratched and or allowed to rust.
The great advantage of the torsion bar vs a coil spring is the ease of correcting for a bit of relaxing springs will do over time.

I need to admit that I am a bit unsure about spring temper fading with time. If however it does exist it is very minor.

We all know about re arching leaf springs. They are the same stuff and the arching process just gives them back the original curve they need. A torsion bar has the advantage in that we can do it for ourselves.

A question I have is to what standard of quality are aftermarket torsion bars made to?---(The recipe of the steel and the tempering process)--- And if they are very close (as I would expect) Is the expense of changing them worth the effort vs just adjusting what we have?

Perhaps we spend extra money way too often for a scrap of piece of mind. In this case it is not a big safety issue. just a ride quality thing.

[HPP]

Not much new too add to the above other than if you are stepping up the size/rate, then you also need to step up the shocks to better control them. Shock technology is similar to camshaft technology, and it has advanced a lot in the decades since these cars were new. It is now entirely possible to have much higher spring rates delivering a better and more comfortable ride with increased road handling capability because of shock technology.

[Mike DC]

 
Some of the original bars are sagged so low by now that the adjuster bolt will be near/at the top just to keep the original height.  A few more years of sagging and you will be wishing you had replaced them now.

Other sets of original bars still have a lot of height left in them today.  Just depends on the car's mileage/experience/etc.



I would replace the T-bars simply to get the rate increasted a bit.  It's not a safety issue on a cruiser, just a handling preference. 

The rear leafs don't need to be stiffer for a cruiser.  (The stock 6-leaf R/T rear springs were arguably too stiff for anything other than drag stripping.)