Lower Control Arm and Strut issues

[ChargerRT69]

I am assembling my '69 Charger front end on a stand and having an issue with my driver's side lower control arm pulling off the shaft as I tighten up the strut. What could be causing this?


I have taken it apart, checked it out and reassembled with about the same effect. It is as if the strut arm is almost too long once I put the bushings in place. I tried it without the strut bushings once and the LCA slide all the way onto the shaft.


Here are some pictures

[Kern Dog]

With no torsion bar in place and under tension, the urethane bushing may allow the control arm to slip back. Those ARE urethane, right?

[Nacho-RT74]

That's the problem with poly bushings. It needs to be accomplished with poly strut rod bushings too. I made the mistake of use rubber bushing on strut rod with poly LCA bushing and the driver side LCA slided back enough ( just like that on pic ) to compress the strut rod bushing enough to allmost break it.

Still with T bar mounted and tensioned. It happened on the use, not during installation.

[ChargerRT69]

With no torsion bar in place and under tension, the urethane bushing may allow the control arm to slip back. Those ARE urethane, right?

The pivot shafts are Hotchkis Sport suspension set (greasable) with polyurethane bushings.

I was concerned that once everything is bolted into the car and I go to install the T bars I would have more difficulties since it keeps sliding rearward. I know the strut will keep it on, but wondered if there was something wrong that would cause this to occur.

Thanks

[ChargerRT69]

That's the problem with poly bushings. It needs to be accomplished with poly strut rod bushings too. I made the mistake of use rubber bushing on strut rod with poly LCA bushing and the driver side LCA slided back enough ( just like that on pic ) to compress the strut rod bushing enough to allmost break it.

Still with T bar mounted and tensioned. It happened on the use, not during installation.

I will have to look.... I think that the strut bushings are rubber and not poly. Wow, thank is what is causing this to occur?

[b5blue]

Factory LCA bushings are press fit. (They can't move if proper.) 

[Nacho-RT74]

Factory LCA bushings are press fit. (They can't move if proper.) 

once rubber is broken from the metallic bushing ( inner or outer ) they could be moved. Of course that will be the first step to the failure process

[ChargerRT69]

So been doing some more thinking on the old original struts. They do not look bent, but could there be something wrong with them? After years of being used, would I better off replacing them? In what ways can the struts go bad? What can I check?

If I should replace them, do I bite the bullet and look at adjustable struts? One thing leads to another, but I have also been thinking about the original sway bar and torsion bars.... should they be replaced? I do not plan on making this an autocross type of car, mostly street, but occasional spirited driving. Maybe I will start another thread to ask some of those questions for the best setup.

[Nacho-RT74]

strut rods just need to be replaced if bent or threads gone.

need to say that our cars are not a piece of precision on how they are built or welded... maybe K member is not symmetrical and one of the sides of the K member arms is welded shorter or at diff angle. With stock bushing that will be hard to notice because it will absorv that, but being poly where the LCA pivot shaft is free!!! who knows.

6 or 7 months ago a buddy from FBBO found his 74 K member shock/UCA tower incorrectly welded onto the K member crade. Had to cut the weld seam and relocate it! 45 YEARS LATER!!! it was 3/4" off compared with the other side


( also the sway bar link provision )

[b5blue]

So been doing some more thinking on the old original struts. They do not look bent, but could there be something wrong with them? After years of being used, would I better off replacing them? In what ways can the struts go bad? What can I check?

If I should replace them, do I bite the bullet and look at adjustable struts? One thing leads to another, but I have also been thinking about the original sway bar and torsion bars.... should they be replaced? I do not plan on making this an autocross type of car, mostly street, but occasional spirited driving. Maybe I will start another thread to ask some of those questions for the best setup.

Rolled on a flat surface you'll see a wobble if bent. I replaced mine with solid mount adjustable just to eliminate flex.   

[ChargerRT69]

strut rods just need to be replaced if bent or threads gone.

need to say that our cars are not a piece of precision on how they are built or welded... maybe K member is not symmetrical and one of the sides of the K member arms is welded shorter or at diff angle. With stock bushing that will be hard to notice because it will absorv that, but being poly where the LCA pivot shaft is free!!! who knows.

6 or 7 months ago a buddy from FBBO found his 74 K member shock/UCA tower incorrectly welded onto the K member crade. Had to cut the weld seam and relocate it! 45 YEARS LATER!!! it was 3/4" off compared with the other side


( also the sway bar link provision )

Thanks I appreciate real life feedback!

[ChargerRT69]

Rolled on a flat surface you'll see a wobble if bent. I replaced mine with solid mount adjustable just to eliminate flex.   

Thanks! What make is your solid mount adjustable strut?

[b5blue]

Hotchkis was cheaper.

[469 runner]

This is one place where I will not use anything except the rubber bushing.  The rubber bushing is a press fit into the lower control arm and onto the pivot shaft.  It acts to retain the control arm to the crossmember, but also acts as a small torsion spring.  Urethane is not the way to go here.

[ChargerRT69]

I am continuing on with this thread in hopes someone could help shed some light.

I started this thread with issues of the LCA. As I got deeper into this and suggestions from various people on this forum and others, I realized that I needed to do some more work. I ended up getting some reinforcement plates for my LCA, some adjustable strut rods from Firm Feel along with several other suspension improvements. As I was putting the LCA's back on the k-frame with the adjustable strut rods when I noticed a difference in the bumper mounting plate (see pics). It made me wonder if one of these are from a different car model.

Which one is the correct one for a 1969 Charger R/T model?

[birdsandbees]

Plate with 4 spot welds is correct...

[Kern Dog]

You should remove and toss those rotor shields. They trap heat. They came on new cars as a guard against mud and rocks getting on the rotors. You're not going to drive this car on muddy roads, are you?

[jlatessa]

Yes, you  certainly won't see a weld bead like that second plate from the factory, at least I haven't.

LOL... Joe

[birdsandbees]

Yes, you  certainly won't see a weld bead like that second plate from the factory, at least I haven't.

LOL... Joe

Actually the 2nd bead welded plate is probably from a 1970, but they would have had to add the '69 style sway bar tab.

[ChargerRT69]

Thank you for all the feedback, I'll have to take a closer look to see if the sway bar bracket was added after the fact.

There is a wealth of knowledge on this form and I appreciate all the help!