Operation Lower Control Arm bushings;
Ok, so in the process of replacing my friend's front strut bushings in his 71 six pack Challenger R/T I discovered during my post- teardown inspection that the LC arm bushing are shot. So, with that said that needs attention. The old way of thinking for me was stay away from the poly LC arm bushing since they always squeak. Has the technology improved with a better product?
Thoughts?

I bought a set of poly for my roadrunner and get 0 squeak with Firm Feel inc. greasable lower control arm pins. www.firmfeel.com

Very nice cars by the way!

Poly, only way to go, they don't squeak if installed/lubricated properly, I've been installing nothing but poly on my customers vehicles as well as my own for 30+ yrs, never had a poly failure....


Mike

IMHO, needs to be matched with poly strut rods bushings... if still rubber there will be smashed easily, because poly allows to the control arm get in and out and rubber won't hold it. That was my experience using poly there and keeping rubber on strut rods

Agreed, Poly through out, toss the rubber....

Does the poly stiffen, slowdown or restrict movement? Would it be detrimental or advantageous for a strip or street/strip car?

Rubber.
Exception would be nylon with greasible 'pins' for situation where want to minimize every bit of suspension compliance.
Penalty is more maint and slightly higher NVH.
Reaction strut bushings are place I would consider poly
But then strut rod placement must be checked and if needed, bushing thickness modified.
Otherwise you may find the LCA being pushed back (or forward) from its proper position - especially when using nylon or poly LCA bushings.

hi,

Prothane long life no squeek !

I understand the concept of what you're saying. If it doesn't take this thread too far into the weeds, can you describe how strut rod placement is checked?

With the LCA installed @ static ride height when the strut rod is attached it shouldn't push or pull {deflect} the LCA too much in either direction.

Point of order, the LCA and the "brake struts" are designed with conflicting arcs. If there was for arguments sake, zero compliance in the system, thee wheel would locked solid. vertically. with no compliance There has to be compliance somewhere. I believe Mopar designed that in. The normal thought is to just reduce compliance and have better handling, however, nobody seems to ever consider when they have gone to far. I would say too far would be having the brake strut over control (ie bump steer) the LCA arm, I personally would rather the LCA arm control the brake strut ( the location of whatever compliance is needed). That being said, grease able pin Delrin bushings in the LCA and rubber struts real tight would check off most of the boxes, IMO.

this is a question I asked in the autocross section for no answer really .
Which brand Delrin lca bushes ?
Normally I would prefer stock Moog lca bush wondering if Delrin might help for street/strip
I actually have the HD taxi strut rod bushed from MOOG , they seem a whole lot stronger than standard type . Have integral washers .
thanks ,

Tex

Do NOT, under any circumstances at this time, buy Moog lower control arm bushings. They have a well-documented current problem with fitment to the pivot pin. Specifically, the pin is too loose in the inner sleeve of the bushing.

Sure. I made a webpage about it long ago. It was particulalry an issue with the poly strut bushings when used on A-bodies, or at least the a-bodies with the earlier struts.

Basically I test fit the LCA and strut assembly without the strut bushings.
With no bushings, then measurements could be made for reference. This is the position of the strut relative to the K frame where the strut and LCA are not being pushed back (or forward).
Prob best to have the LCA at a somewhat horizontal position (representing typical ride ht) not hanging down.

http://www.heritech.org/cuda/bushings.html

I'm using nylon LCA from firmfeel and their greasable pins. Don't know if its a listed item. If not, tell Dick you are autocrossing and thats your interested.
They do add a little vibration to the steering wheel on certain highways,
The advantage over polyu is they will not plastically deform - which is possible when running road race or autocross compounds.
If you're looking to reduce every compliance point you can, and some of us go there, then nylon over rubber is another small gain.
small - the rubber isn't that thick or that compliant - but a degree of camber under load in competition could be worth it...

Shouldn't matter. The shock should be controlling the damping.
If you're using 90/10 shocks, then maybe, but I doubt it.

The use is mostly for reducing compliance in cornering, or in the case of the strut rods, braking.

Thanks Mattax .
Will look them up . I know Bergman also do a delrin bush , but i think they recommend heim joint strut rods at same time and no greaseable pivot pin
Vibration is no issue , i have 80 profile tyres . Lots of comfort there .
I would think it might free up lca movement as there is no torsional twist/bind like a factory bush

Tex

I had the Cuda aligned last year. Called around and found an experienced independent shop where the owner does the alignments. Although he didn't have a lot of experience with our cars, he was willing to stay at it until he got it. We used the method outlined here to align, took it for a drive and noted a drift, put it back on the rack, made an adjustment, drove it again and it was good. Cost $75.

He had me get in the car while it was on the rack. I was really surprised how much the alignment changed with my 200lbs in the driver's seat. Most of the setting indicators went from green (good) to red. It changed even more with a passenger. All the setting indicators went from green to red. I didn't tell the wife cause she is sometimes reluctant to go with me to a show on a hot afternoon. And I don't want her to have any more excuses to say no.

After 40+ years of hard-core autocross racing, I've rebuilt my front suspension and installed the Firm Feel Nylon bushings (not the poly).. I think the Nylon are actually Delrin material.

The old factory rubber LCA bushings had been replced once before (by me... about 30 years years ago)... and they did show signs of deterioration. Also, I went with poly strut bushings.

So, I should be driving the car again this summer (new engine, etc).. I'll let you know what my thoughts are about the new bushings. Handling is my #1 priority.