Moparts

Problem installing torsion bars!

Posted By: JF_Moparts

Problem installing torsion bars! - 06/19/23 02:03 AM

I've removed and replaced torsion bars a bunch of times, but I have a problem that I can't figure out and I think I'm just forgetting something. Here's the problem:

It's a 70 Challenger. The old bars are out. During removal I raised the car, removed the top bump stop, and loosened the LCA adjuster bolt so it hangs loose. Then I removed the bar.

Now I'm putting the new bars in and the hex socket in the LCA is NOT aligning AT ALL with the torsion bar. I even tried putting the old one back in and same problem. What am I missing here? Is there some secret way to get that LCA hex to rotate so I can get this aligned? I also removed the top nut on the shock just to get more suspension travel, just in case. I'm going crazy.

Any advice is appreciated. Thanks.

(In the meantime this wonderful Mopar is stuck on jack stands attracting the attention of nosy neighbors.)
Posted By: Moparite

Re: Problem installing torsion bars! - 06/19/23 10:47 AM

Are you installing the correct one on the correct side? They are different if i recall.
Posted By: JF_Moparts

Re: Problem installing torsion bars! - 06/19/23 05:30 PM

Yes, I'm following the L and R markings.

I did find a message on another board suggesting loosening the bolt on the LCA pivot rod, that goes into the K frame. I had never done this before for torsion bar swapping so I'm slightly hesitant.

Thanks.
Posted By: A990

Re: Problem installing torsion bars! - 06/19/23 05:57 PM

Originally Posted by JF_Moparts
Yes, I'm following the L and R markings.

I did find a message on another board suggesting loosening the bolt on the LCA pivot rod, that goes into the K frame. I had never done this before for torsion bar swapping so I'm slightly hesitant.

Thanks.


I learned long ago doing this makes the hexes go together. It allows some wiggle room and speeds up the install/removal time.
Posted By: JF_Moparts

Re: Problem installing torsion bars! - 06/19/23 06:28 PM

Originally Posted by A990
Originally Posted by JF_Moparts
Yes, I'm following the L and R markings.

I did find a message on another board suggesting loosening the bolt on the LCA pivot rod, that goes into the K frame. I had never done this before for torsion bar swapping so I'm slightly hesitant.

Thanks.


I learned long ago doing this makes the hexes go together. It allows some wiggle room and speeds up the install/removal time.


Good to know. It is a simple process? Loosen the bolt, slightly rotate the hex, get the bar in, and then tighten the nut again?

Thank you.
Posted By: Sniper

Re: Problem installing torsion bars! - 06/19/23 09:13 PM

I've had to force the LCA further than it wants to go in order to line them up, just using my body, no need for anything serious. But I don't go for real thick bars either. IIRC, once the bars get above a certain rate they lessen the offset, not sure how that might apply here though.
Posted By: JF_Moparts

Re: Problem installing torsion bars! - 06/19/23 09:28 PM

Originally Posted by Sniper
I've had to force the LCA further than it wants to go in order to line them up, just using my body, no need for anything serious. But I don't go for real thick bars either. IIRC, once the bars get above a certain rate they lessen the offset, not sure how that might apply here though.


Yeah, regarding the offset Firm Feel confirmed that it is different by about 20 degrees (roughly, don't quote me) than stock. FF also suggested popping open the upper ball joint, which will be my last resort.

In my case it looks like I need to rotate the LCA down by about 30 degrees. I'm assuming pushing the LCA up and installing the bar there would mean I was inserting the bar in an incorrect position, by 1/6 (one hex point) off. Not sure how that would affect the load on the bar.
Posted By: A990

Re: Problem installing torsion bars! - 06/19/23 11:41 PM

Originally Posted by JF_Moparts
Originally Posted by A990
Originally Posted by JF_Moparts
Yes, I'm following the L and R markings.

I did find a message on another board suggesting loosening the bolt on the LCA pivot rod, that goes into the K frame. I had never done this before for torsion bar swapping so I'm slightly hesitant.

Thanks.


I learned long ago doing this makes the hexes go together. It allows some wiggle room and speeds up the install/removal time.


Good to know. It is a simple process? Loosen the bolt, slightly rotate the hex, get the bar in, and then tighten the nut again?

Thank you.

Yep. Back out the nut a thread or too, install the bar, and use it to reseat the LCA. To remove stuck bars, back the LCA nut off till about haf the threads are engaged, remover the rear retainer clip. Then use a deadblow hammer or wood block and smack the shaft backwards to release the rear hex, then usually you can grab the bar and slide it out of the LCA hex.
Posted By: JF_Moparts

Re: Problem installing torsion bars! - 06/20/23 04:28 PM

Just one clarification - what did you mean by "reseat the LCA"?

Thanks.
Posted By: A990

Re: Problem installing torsion bars! - 06/20/23 06:16 PM

Originally Posted by JF_Moparts
Just one clarification - what did you mean by "reseat the LCA"?

Thanks.

Once you get the hex into the LCA, rather than pull the arm into the K-member, push the TB to keep it fully bottomed in the socket.
The whole idea is to make certain the retainer groove is fully opened for the clip.
Posted By: JF_Moparts

Re: Problem installing torsion bars! - 06/20/23 08:54 PM

Originally Posted by A990
Originally Posted by JF_Moparts
Just one clarification - what did you mean by "reseat the LCA"?

Thanks.

Once you get the hex into the LCA, rather than pull the arm into the K-member, push the TB to keep it fully bottomed in the socket.
The whole idea is to make certain the retainer groove is fully opened for the clip.


I'm sorry, now I'm 100% confused.

- "Hex into the LCA" means the hex end of the TB into the LCA socket?
- "Pull the arm into the K member" - I'm not sure what you mean, sorry.
- "Push the TB" - I assume you mean pushing the TB from the rear of the car towards the front to seat it in the LCA hex socket? (I have the TB removal tool as well)
- The retainer groove in the crossmember south of the trans, right?

The entire front suspension is assembled. I've kept the tires on as well, for weight on the LCAs.

Thanks.
Posted By: JF_Moparts

Re: Problem installing torsion bars! - 07/03/23 04:50 AM

Ok, so I finally got it all done. I thought I'd share what the solution was, for those looking to do the same job.

I needed to loosen the 15/16" nut in the K frame just in front of where the LCA pivots on the frame. This is a nut on the shaft that goes from the frame directly into the LCA and LCA Hex socket and also into the LCA bushing. Once I did that, I was able to move the hex socket back and forth and align it with the torsion bar.


What's weird, though, is that I never had this problem with my other cars. The only difference I can think of is my other cars are polyurethane LCA bushings and this car is rubber. Maybe the rubber bushing binds the LCA adjuster?

Thanks to all who offered advice, it helped.
Posted By: ruderunner

Re: Problem installing torsion bars! - 07/03/23 11:14 AM

Yes, the bushing does restrict the movement of the arm. Note, the pivot bolt should be tightened AFTER the ride height is set
Posted By: 375inStroke

Re: Problem installing torsion bars! - 07/06/23 06:19 AM

Originally Posted by ruderunner
Yes, the bushing does restrict the movement of the arm. Note, the pivot bolt should be tightened AFTER the ride height is set

Ride height has no affect. Tighten the pivot bolt after weight on wheels. After that, adjusting ride height just rotates the LCA around the front torsion socket. The point being you can make adjustments later with no ill effects.
Posted By: ruderunner

Re: Problem installing torsion bars! - 07/06/23 04:44 PM

Had to think about that but yes.
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