Author Topic: Adjusting torsion bar  (Read 2603 times)

Offline dwbiggs

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Adjusting torsion bar
« on: March 08, 2005 - 10:34:10 AM »
Which is correct for adjusting torsion bar?  I have the LCA's, hangin loose, and the nut just finger tight to keep the LCA in position.  The T-bar adjuster arm is clocked to a 4:00 (L) and 8:00 (R) position (looking from front of car) and have locked in the clips.  Do I now load up the bars and then once the ride height is set torque the LCA nut down or torque it down then adjust torsion bar? 

Thnaks, Dan

1974 Challenger Rallye - 440+.040, 0 decked, 10.5:1, Ross Pistons, Hughes 3844 cam (238/244, .536/.540), Eddy RPM manifold, Eddy aluminum heads, Holley 750, TTI headers, .96" T-bars, IAS shocks, 1 1/8" front sway bar, 3/4" rear sway bar, XHD 6 leaf springs, Firm Feel stage 2 steering box.




Offline dgc333

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Re: Adjusting torsion bar
« Reply #1 on: March 08, 2005 - 03:37:14 PM »
If you are using stock style rubber bushings you should not torque the lower control arm pivot bolt until after the car is sitting at it's final ride height. This goes for the upper control arm bolts too.

The reason is the inner and outer shells of the control arm bushings are bonded to the rubber material in between. Motion in the suspension is obtained by twisting the rubber between the shells. You want the bushings in a neutral position at ride height so they are not allways being loaded which can/will result in premature failure.

If you are using poly bushings it doesn't make a difference because the bushing shells slide on the poly material.

Offline dwbiggs

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Re: Adjusting torsion bar
« Reply #2 on: March 08, 2005 - 03:47:50 PM »
Thanks dgc333,

So my next move is to make sure everything is untorqued, adjust the t-bars up to a normal ride height, let car down and check...if right tehn torque down LCA and UCA?

Dan

1974 Challenger Rallye - 440+.040, 0 decked, 10.5:1, Ross Pistons, Hughes 3844 cam (238/244, .536/.540), Eddy RPM manifold, Eddy aluminum heads, Holley 750, TTI headers, .96" T-bars, IAS shocks, 1 1/8" front sway bar, 3/4" rear sway bar, XHD 6 leaf springs, Firm Feel stage 2 steering box.

Offline dgc333

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Re: Adjusting torsion bar
« Reply #3 on: March 08, 2005 - 05:07:56 PM »
Yep!

I put the front tires on ramps and jack stands under the rear axle so the car is supported as it would be on the ground and at the same attitude. Makes it easier to get under the car to adjust the torsion bars and tighten everything up once you are down.

Also, each time you make an adjustment on the torsion bar adjusters bounce the front end a couple to times to get everthing to settle in.

Offline 340challconvert

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Re: Adjusting torsion bar
« Reply #4 on: May 12, 2016 - 09:51:45 AM »
If you are using stock style rubber bushings you should not torque the lower control arm pivot bolt until after the car is sitting at it's final ride height. This goes for the upper control arm bolts too.

The reason is the inner and outer shells of the control arm bushings are bonded to the rubber material in between. Motion in the suspension is obtained by twisting the rubber between the shells. You want the bushings in a neutral position at ride height so they are not allways being loaded which can/will result in premature failure.

If you are using poly bushings it doesn't make a difference because the bushing shells slide on the poly material.
Good Tip
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Offline Mopar Mitch

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Re: Adjusting torsion bar
« Reply #5 on: May 13, 2016 - 12:17:15 PM »
Now would be the time to get a set of 4-wheel scales (or alt least a pair for the front) and balance the corner weight, in particular the fronts... side-to-side... easy with the TB adjusters.   The ride heights may not be exactly the same (difference could be ~1/4"... maybe ~1/2" ... but very close... BUT.. you'll get a better handling setup with balanced side-to-side weights (with driver's weight in the driver's seat).
Autocross/road racers go in deeper... and come out harder!

See  MOPAR ACTION MAGAZINE, AUGUST 2006 ISSUE for featured article and details on my autocross T/A.

Offline 72bluNblu

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Re: Adjusting torsion bar
« Reply #6 on: May 14, 2016 - 02:43:53 AM »
Don't adjust the torsion bars with weight on the suspension, especially if you're under the car. The torsion bar adjuster threads can strip when adjusted under load. That's never a good thing, but if you're under the car when the torsion bar adjuster goes away you'd better hope the bump stop comes into play before you do.

Also, "bouncing" the car is not enough to settle the suspension. There is a dynamic aspect to it as well, you have to roll the car to fully settle it. Really, until you've driven it around the block you're not at the final height for a given setting.

Offline 74 challenge

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Re: Adjusting torsion bar
« Reply #7 on: May 20, 2016 - 12:07:38 PM »
Just bringing this back up since I am looking at lifting my font end by 1/2 an inch or so.

I should take the weight of the car off the front wheels, Screw in the adjusting bolt on the lower control arm equally on both sides ~3 or 4 turns, drop the car back down, bounce the car around/ drive it around the block and verify.

Is it really that simple?

I'm lifting it since it has scraped slightly on large bumps and the past few winters has increased the amount of bumps on the roads.
1-8-4-3-6-5-7-2

Offline YellowThumper

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Re: Adjusting torsion bar
« Reply #8 on: May 20, 2016 - 12:17:03 PM »
Yes it is that simple.
But the change will alter your alignment slightly.
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Offline 74 challenge

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Re: Adjusting torsion bar
« Reply #9 on: May 20, 2016 - 12:46:24 PM »
Yes it is that simple.
But the change will alter your alignment slightly.

the car needs an alignment anyways so I am not too concerned about that.

Just need to adjust that and fix the exhaust and put some miles on it.
1-8-4-3-6-5-7-2