Lower Control Arm Bushing

[basstrix]

On my car, the Lower Control Arms (LCA) have migrated forward and have rubbed on mounting framework. This is presumably related to the Strut Rods pulling forward for positive Caster. Wondering if any of you have experience tack welding the bushing to the control arm to prevent the bushing from moving, relative to the arm. My concern would be to damaging the rubber just inside the tach weld.

 

[Steve McMahan]

Post pics of what you’re describing. I think it might help.

 

[Cleveland Crush]

As stated post photos, but it sounds like in your desire to gain more caster the lca is now binding. We all want more caster, but our factory front ends were designed for zero to 1 degree positive max. Anything more, binding sets in. If you weld the steel bushing sleeve the binding will still be there wearing the bushing. How much caster are you running?

 

[basstrix]

The attached is a depiction of what has happened. The LCA's were part of a kit I bought from California Mustang back in the 80's. Maybe they were just crap control arms and the press fit of the bushing-to-Control Arm was not tight enough? One of my rancheros has a similar situation, but not as bad as the mustang. The movement of the LCA vs the bushings happened gradually.

In the attachment, I simulated the bushing being off center. The gray pieces represent the frame support for the inner pivot of the LCA.

@Cleveland Crush: A few months back, I measured -2.2 deg on the left and -1 on the right. Toe and camber were in spec. My turn plates didn't have angle pointers, so the values probably have some error. Since then, I added pointers to the plates.

I'm planning to target 3 degrees of caster. To achieve that, will require a shim behind the forward bolt of the UCA. Previously, I posted with the characterization table and graph, for anyone interested. The table and graph was a result of a kinematic CAD model I created to characterize the suspension's behavior. The focus was on shim thickness vs caster angle.

 

[Bentworker]

You could buy an Opentracker LCA kit that converts it to a heim style joint

 

[Cleveland Crush]

The attached is a depiction of what has happened. The LCA's were part of a kit I bought from California Mustang back in the 80's. Maybe they were just crap control arms and the press fit of the bushing-to-Control Arm was not tight enough? One of my rancheros has a similar situation, but not as bad as the mustang. The movement of the LCA vs the bushings happened gradually.

In the attachment, I simulated the bushing being off center. The gray pieces represent the frame support for the inner pivot of the LCA.

@Cleveland Crush: A few months back, I measured -2.2 deg on the left and -1 on the right. Toe and camber were in spec. My turn plates didn't have angle pointers, so the values probably have some error. Since then, I added pointers to the plates.

I'm planning to target 3 degrees of caster. To achieve that, will require a shim behind the forward bolt of the UCA. Previously, I posted with the characterization table and graph, for anyone interested. The table and graph was a result of a kinematic CAD model I created to characterize the suspension's behavior. The focus was on shim thickness vs caster angle.



View attachment 92790

Our factory LCA pivot point does not like much more then about 1 degree positive caster at the illustrated joint. Doesn't matter if you shim the upper control arm or tighten the strut rod to gain caster, it's going to bind right there at the lower bushing pivot point! Live with about 1 degree positive caster or go aftermarket parts for more positive.

 

[judge]

On my car, the Lower Control Arms (LCA) have migrated forward and have rubbed on mounting framework. This is presumably related to the Strut Rods pulling forward for positive Caster. Wondering if any of you have experience tack welding the bushing to the control arm to prevent the bushing from moving, relative to the arm. My concern would be to damaging the rubber just inside the tach weld.

The movement or positioning forward or backward doesn't make a difference. But if you wanted to weld it, cooling off with water between tack welds would limit any damage.

 

[rcadd1ct]

I went Opentracker then I did his reinforcements.

I also boxed the inner then trimmed them for more clearance

I used a brake piston expander tool to widen my bent LCA frame pocket.

Before and after pix.

 

[Cleveland Crush]

Nice work on the control arms @rcadd1ct

 

[basstrix]

I went Opentracker then I did his reinforcements.

I also boxed the inner then trimmed them for more clearance

I used a brake piston expander tool to widen my bent LCA frame pocket.

Before and after pix.

Your first picture looks like what I have going on. Did you have rubber or polyurethane strut rod bushings in the "before" configuration?

 

[Otto]

I wouldn't worry about damaging the rubber inside the bushing. Only a small portion of the bushing will heat up. Just remember to make it a quick tack. I use original control arms that are boxed and lower bushings double tacked. If you have a car that will mostly see the street, I feel that's the way to go.

 

[rcadd1ct]

Your first picture looks like what I have going on. Did you have rubber or polyurethane strut rod bushings in the "before" configuration?

Rubber

 

[rcadd1ct]

Nice work on the control arms @rcadd1ct

Thx.

I wish I could weld better, but have to start somewhere.

 

[mjlan]

I wouldn't hesitate to put some healthy tacks on it to hold it in place. Just hit it with a wet rag after you weld and it will be fine.

 

[Aus73Mach1]

Same thing happened to one of mine. Just poor repro quality I think. I put 3 tack welds around the outer bush. Cool it quickly as others have suggested and the rubber won't be damaged.

 

[71fordramair]

eccentric eliminators go along way on freeing up binding caused by hi torque on LCA eccentrics.

 

[rcadd1ct]

eccentric eliminators go along way on freeing up binding caused by hi torque on LCA eccentrics.

Get it aligned with the eccentric then swap to eliminators.

Also I prefer the Opentracker ones as you don’t have to remove the bolt to make changes.