Lower control arm stiffening plates

[dartswinger71318]

I'm in the process of restoring my 69 Dart , starting the suspension and brake system with an original Kelsey Hayes 4 piston disc system. When I dropped the LCA's I noticed how much slop there was so I fabricated stiffening plates to help alleviate the slop. I modeled my plates from aftermarket plates I've seen. Hoping this will help the drivability when its completely finished.

 

[coloradohill]

I did mine a few years ago and used a method similar to this to remove the factory slop.

 

[pishta]

Nice, looks like a good weekend project. What gauge metal?

 

[dartswinger71318]

Nice, looks like a good weekend project. What gauge metal?

11 ga.

 

[RedFish]

Ties dont have to be so fancy as what aftermarket offers. They're over engineered in my opinion. A few pieces of about 1 inch wide flat bar will serve the purpose and not as likely to collect gravel.

 

[67Dart273]

Ties dont have to be so fancy as what aftermarket offers. They're over engineered in my opinion. A few pieces of about 1 inch wide flat bar will serve the purpose and not as likely to collect gravel.

Well, lolol, they have to look like SOMETHING for all that money

 

[Jim Lusk]

Ties dont have to be so fancy as what aftermarket offers. They're over engineered in my opinion. A few pieces of about 1 inch wide flat bar will serve the purpose and not as likely to collect gravel.

I've made my own stiffening plates, but at around $25/pair for aftermarket they are worth it in my opinion. NOW, if I had a plasma cutter or a CNC water jet, I'd make my own...

 

[72bluNblu]

Ties dont have to be so fancy as what aftermarket offers. They're over engineered in my opinion. A few pieces of about 1 inch wide flat bar will serve the purpose and not as likely to collect gravel.

The point of the aftermarket plates is to box the control arm. A few ties does not accomplish that. The more surface area that the boxing plate has the better the control arm will resist twisting.

A few ties are better than nothing, and they’ll help keep then sides of the LCA from spreading apart. But they’re won’t be as effective at boxing the LCA which means you won’t get the same torsional strength.

 

[dartswinger71318]

Ties dont have to be so fancy as what aftermarket offers. They're over engineered in my opinion. A few pieces of about 1 inch wide flat bar will serve the purpose and not as likely to collect gravel.

I'm a Union Sheetmetal fabricator by trade, I had access to the equipment it took about 5 minutes to complete. I think they look as nice as the aftermarket plates, and didnt cost a dime.

 

[autoxcuda]

The point of the aftermarket plates is to box the control arm. A few ties does not accomplish that. The more surface area that the boxing plate has the better the control arm will resist twisting.

A few ties are better than nothing, and they’ll help keep then sides of the LCA from spreading apart. But they’re won’t be as effective at boxing the LCA which means you won’t get the same torsional strength.

The area going across each side ties them. The wider plate just overlaps the flanges on the bottom. Extra weight.

 

[72bluNblu]

The area going across each side ties them. The wider plate just overlaps the flanges on the bottom. Extra weight.

If that worked the factory bump stop plate would take care of it.

Overlapping the flanges the entire length of the control arm adds a significant amount of stiffness to the control arm, and the plate boxing in the entire open bottom does more than just keep the sides from spreading apart- it adds torsional resistance that you won't get from just a few straps. With the straps the area between the straps can still flex and twist.

The plates are super easy to make too, piece of plate, a sawzall and a hole saw and you're set. The difference in weight is a handful of ounces.

I'm in the process of restoring my 69 Dart , starting the suspension and brake system with an original Kelsey Hayes 4 piston disc system. When I dropped the LCA's I noticed how much slop there was so I fabricated stiffening plates to help alleviate the slop. I modeled my plates from aftermarket plates I've seen. Hoping this will help the drivability when its completely finished.View attachment 1715563397 View attachment 1715563399

Nice job with the plates at the end with the torsion bar lever. Even with the aftermarket plates I found that the sides of the LCA will still spread apart some at that end, which is the most important area for controlling flex in the UCA. I added a strap to mine there as well, although not quite as large as the one you added. That's not going anywhere!

 

[autoxcuda]

If that worked the factory bump stop plate would take care of it.

That would leave the LCA with a U-channel configuration. Connecting the sides of the LCA in the bottom crates a box.

Overlapping the flanges the entire length of the control arm adds a significant amount of stiffness to the control arm, and the plate boxing in the entire open bottom does more than just keep the sides from spreading apart- it adds torsional resistance that you won't get from just a few straps. With the straps the area between the straps can still flex and twist.

Shouldn’t be much torsional twist on both ends around the line between the ball joint and LCA. Unless the strut rod is on another arc. The ball joint can’t directly put any twist in the LCA since it is a ball joints that move freely in any direction.

Between the ball joint and strut rod I can see forces that could twist. That’s a small distance with a solid forged tall insert to spread load. Most all LCA I’ve seen, had, and personally bent myself were around the ball joint to strut rod area.

One on left is bent

 

[RedFish]

OK. If/when my A-body ever transitions from normal driving to demolition derbys, I'll reconsider the counterpoints here. Happy moparing

 

[512Stroker]

The area going across each side ties them. The wider plate just overlaps the flanges on the bottom. Extra weight.

View attachment 1715564354

Auto did you fab those plates or purchase them?
If so who from?

 

[autoxcuda]

Auto did you fab those plates or purchase them?
If so who from?

That was just a picture I stole off the net for an example of a the wide stiffening plate kits

This is what I did in 1997:

One 1” strap back near LCA bushing

One 1” strap under sway bar tab

One 1” strap under strut rod.

Looking back if should have put one in the middle.

At the time, I had ideas of competing in SCCA solo II E-street prepared class. Reinforcing was not legal. The heavy arc welding looks sorta stock-ish

Since I did these in 1997... I’ve been off course at Willow Springs a couple times.

1st time:
-I bent one front steel rallye rim
-bottomed out a shock (upper frame hole dimpled up
-scuffed the bottom front valence and fender
-re-mounted tire to get out rocks and earth stuck between bead and tire

2nd time
-dinged up one side of set of brand new TTI headers. From the direction of the slide.
-re-mounted tire to get out rocks and earth stuck between bead and tire
-disconnected rear sway bar afterwards.

Was.... a spotless brand new engine....

After both times....

LCA’s were not bent and aligns fine.

 

[Tony Barracuda]

When adding the end plates where the torsion bar levers are
how free should the levers be to rotate ? i added the end piece
and one still has a little play and the other is pretty tight. So the lever
doesn’t move as freely as the other.

 

[72bluNblu]

When adding the end plates where the torsion bar levers are
how free should the levers be to rotate ? i added the end piece
and one still has a little play and the other is pretty tight. So the lever
doesn’t move as freely as the other.

When the suspension is loaded the adjuster lever and LCA move together. The only time the lever and LCA move separately from each other is when you’re adjusting the position of the lever to set the ride height. So there really doesn’t need to be any play between the lever and LCA at all. I usually set them up so they turn without any resistance, but there’s no real side to side play at all.

 

[Tony Barracuda]

Ok one side has a little resistance but has full movement, and the other has a little play. 10 to 12 thou. If I had to guess. When I did the one side a little tight, I made sure to let the lever move a little more, causing a little side play.