Oil resistant is like water resistant. Not oil PROOF.

The difference in our knowledge on the subject is that my side is based on first hand experience and discussion with various manufacturers. Save the google fact checking for someone else please.

Stop in at any diesel repair shop that does front end work and they will confirm what I have conveyed.

While we are googling; see if you can find a poly bushing manufacturer that recommends petro grease. I'd be interested to see the products and which grease they suggest.

I have had several cars with poly front end bushings and driven them year round in 4 seasons (studded tires, mountain passes etc) with no issue other than the lack of lubrication over time. One trip was 15 hours straight to the North Rim of the Grand Canyon in November. I am confident they do the job well with the updates I mentioned previously.

Put it back in and zip your pants up

Where did I say it was OIL PROOF? I didn't You interpreted that

If one has an oil leak that bad they have problems other than bushings

Your knowledge has become of little interest to me because of your attitude and responses

The only diesels I am near are my neighbors acreage tractors.

Nor am I interested in the experiences of Diesel repair shops that do front end work as my vehicles don't see that kind of use nor do I allow a leak to go unrepaired

Where did I say a polyurethane bushing manufacturer recommended petroleum grease? I didn't Once again YOU interpreted that

You ASSumed and misinterpreted a lot from my comments.

So zip it up and I'll ignore your worldly knowledge and you can do the same

-Leaf polys installed 1994/5 on OE leafs (hotchkis leafs -2011).
-Poly strut rods installed 1994-5. Used the lathe in my collage lab class to shorten the rear bushings (Hotchkis rods 2011) .
-Poly LCA bushings went in 1997 with the new K-member. Still installed. Picture in prior post.
-Poly Sway bar bushings... had many sway bars, each with different K-member polys.
-Poly Trans Mount installed sometime prior to 2000. I can't remember exactly. PITA to swap the poly insert. Real tight.

I have well over 60K miles in various configurations of these parts. It was my daily car from 1993 to 2004. I drove it from LA to Iowa State Univ. 1600 miles each way for summer 1993 to 1997 (have pics). Usually within 40 to 60 hours without a hotel room stop (have gas receipts). It’s been on mini trips Chicago and Minneapolis with it a couple times (have pics). Driven in ice storms and snow too (have pics)

While in Iowa, I autocross raced around Iowa usually 60-90 miles each way (Oskaloosa Airport, Ak-Sar-Ben Lincoln NE, Cedar Rapids, Davenport, Marshalltown Go-Kart track…

I did a rings, bearings, rebuilt heads in 1993. It still has original pistons.… by 2011 it was blowing oil out breathers. On the way to a mopar show 50mi from home I caught a rod knock and had it towed home. About 2 years earlier a pro driver was instructing me on track and lost oil pressure. Jim Lusk was there that day. Still took laps later that day, then drove it 85 miles home.

I drove it daily to work from 1999 to 2004 from La Cienega/10fwy to Westlake Village. 36 miles each way over the most traveled stretch of freeway in the US (Sepulveda Pass/405 fwy)

From 2004 to 2015 I drove a company van for work. But my Cuda was my only drivable car I owned otherwise. In 2011 I replaced the original 340 with rod knock for a 416 stroker (450+ hp) I’ve got over 9K miles on that stroker motor right now. I bought a new Challenger in 2015.

Over the years....

-5 different sets of rims (bent one)
-5 different front sway bars
-5 different brands of front shocks (had oil spit out of a couple)
-3 different sizes of Torsion bars
-2 different types of K-members (broke one)
-7-10 sets of tires
-7+ paid professional alignments

So yea. I’ve put some miles on it. And I’ve put some real hard miles on it at that.

Would anyone agree that the base problem is the very design using that bushing?

Back in the day, when these cars were still daily drivers, it was common for the cars to chase every crack in the road. Especially A bodies. The lowers were often worn out by 80,000 miles. I have seen them worn so bad by 100k, that they had worn through the outer shell. B and E bodies were only slightly better. I have never torn down a front end that didn't need the lower replaced. And I mean even back in the 70s and on cars with less than 100k let alone in subsequent decades.

It is a poor design at least in terms of longevity in my humble opinion. It seems obvious that either material can be used successfully but the newer materials have some learning curve to them. Heck, even removing the shells when going back with rubber ones takes some experience or at least some advice. Just a poor design.

A-bodies chasing cracks must have been where my old man learned to AIM for pot holes !
from 1966 on, and especially during my junkyard ownership days of 1972-1984, darts, dusters, swingers, valiants, and all manor of A-bodies were used and abused by my old man, sisters, and my brother.
it was usually on a rotational basis, as when one was crunched or broken, i supplied another.
when riding with my old man in one of his chryslers, when he hit a pot hole, we would give him the devil ! he always responded : "you don't feel those as bad in this as when you're driving that [insert A-body of choice here] !"
what a guy ! he totaled my 64 barracuda when i lent it to him to go to work, so i could service his chrysler [at the time].
it was to be expected when one let him borrow a car, you had a "repair" to do when it came back.

I think because the power steering leaks on top of the drivers bushing, those fail at higher rate than passenger.

Also because the LCA rubber bushing are relatively thin, there is less cushion and less rubber to spread the twisting action. I think that leads to deterioration.

I have a 68 Dart convertible. I'll replace the LCA bushing with rubber on that car. Even though I have extra poly LCA bushing laying around. I want the rubber to soak up the vibrations. Convertible's are rattle traps.

There is nothing wrong with the factory lca bushing design.

I can say for sure my hardware and ideas have been well tested – there are only a few of us that have real test data. Info below is from over 2 decades running lap on Watkins Glenn International Raceway 2x yr/2 days per event. Both cars are street driven and can go anywhere and are not caged -the Charger has a lot more chassis work [welding etc] and less hp than the other but both ran under the lap time “number" at the Glen for a hot full lap 2 min 30 sec. I still have the 70 Charger R/T. Old iron that runs under the number gets a lot of attention.Can your car run 140+ mph with no vibration...mine do

This is why my 2 well mannered nice driving track cars and 4406BBL’s are faster/quicker than the rest. QUOTING: that is not quite the story on adjustable strut rods. They are designed to make up for the [censored], shoddy construction of the cars and especially the k-frames. What you do is put the car on a frame machine or alignment rack and square the frame, get the rear end in the car square, then get the left and right wheelbase the same. You would be amazed at how well these cars align after you do that. Ever measure a dozen mopar strut rods? They vary a lot. Anyway you can do this at home on a garage floor with plumb bobs, rear spring bracket shims, various strut rods and a little time. I set it axle center to lower ball joint center at ride height with just the lower arm in. Lower bushing style is not a big deal to me, but the urethane strut bushings will need that 3/16" removed from the back side to get the wheelbase right. If I remember right the moog improved strut bushings were also too thick. Adjustable struts are fantastic, your alignment guy can get it right real fast without bushing mods, restorations are a different animal, will need various strut rods or the ability to machine or shim them, but you can get it perfect. If you want a bunch of caster, and I would give it more with radials, use the problem solver upper bushings or adjustable upper arms. END Well done!

If the car is not prom queen,or the just drive to the cruise/show type I suggest adjustable struts with the heim joint end – I have yet to have any issues with the heim joint failing. Proper installation. Make me laugh some more at the old wives tales about using a oem rubber lca bushing vs the aftermarket items and torsion bars moving?? Really? The oem lca bushings tear because the front-end height is supposed to set with them at rest or 0 position – pin bolt loose enough – goldilocks. I doubt very much changing the lca bushings to other than oem is going improve the lap time number on the Charger…using oem keeps the ride from becoming like a buck board wagon. Real performance is measured in lap times. I never had one fail even after years of track time. I did have a stock uca failure at the track. Upper a arms should be aftermarket adjustable with plastic type bushings

As far as motion geometry of the suspension….the aftermarket adj struts improve the suspension motion geometry to a very large degree & free's up the motion as well. You should see the difference of alignment geometry between stock and the proper set up as the suspension moves thru it’s motion. The change in the car is amazing and improves the ride.

I will also call BS on green bearings. The last car at the track with that style bearings had an axle failure -snapped the wheel and hub off the bearing and the car almost hit the wall on turn 1. Biggest problem running OEM at the glen was the left rear bearing gets a lot of use and pressure. Clockwise track…….. Properly greased and with tight end play eliminates any problem whatsoever. How do i know that? Well after every event you inspect everything and I saw the gear oil weeping[from seal wear], even though the bearing looked good it was replaced, end play set and it was never ever touched it again. Use oem inner seals! they are still out there. Aftermarket seals are junk.

You are welcome to your opinion. Real world experience has shown since day one that most LCA bushings won't make it to 100k. 80K for A bodies. Been there, done that too many times to believe otherwise.

And since you brought up road racing, how were the T/A cars setup around the K member? The original Dan Gurney/Swede Savage AAR was stored and maintained here locally at R & R Racing for many years and I saw first hand how their suspension was set-up. And the LCA bushing as we know it was not a part of that. You may like the way that Ma Mopar designed that bushing, but Dan Gurney didn't. He made changes.

It was the least expensive way that would last the LIFE of the car, which was about 50-70 thousand miles back then.

Most likely true.