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Polyurethane Upper And Lower Control Arm Bushings

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I just received my set of Energy Suspension polyurethane upper and lower control arm bushings and I have to admit they look terrific. I have always used the common MOOG rubber bushings at about 1/3rd the price so it'll be interesting to see how long these things last. These polyurethane bushings come in three pieces; the heavy wall thickness outer sleeve that gets pressed into the control arm, the polyurethane bushing that is a tight "slip fit", and the heavy wall thickness inner sleeve that is also a tight slip fit. The bushings have 8 grooves in their bores that a special semi-clear lithium soap grease is applied into and that grease is included in the $72 set.

My MOOG bushings failed in about 5 years/100,000 miles because the rubber bushing literally squashed down to nothing which made my caster and camber angles increase over one degree. The polyurethane bushings are a LOT harder than the rubber bushings so I'm hoping they'll last a long time.

How many of you guys are using these polyurethane bushings in your control arms? Are you happy with them so far?
 

Vettehead Mikey

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How many of you guys are using these polyurethane bushings in your control arms? Are you happy with them so far?

They are the single worst thing I ever did to my car by far and I truly regret downgrading the vehicle with them. At the time (almost 30 years ago) I didn't understand how a stock rubber bushing worked and the very logical reasons why they are the exclusive choice for almost every OEM on the planet.

For a guy who passes himself off as an 'expert' on modifications and being a graduate mechanical engineer, you sure got your wire crosses on this one. I actually thought, before opening your post, that you were going to trash them like you have with headers and double pumper carbs.

I should have known better.
 

SVO

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I used the Prothane brand to do the front & rear suspension of my '72 LT-1 car. Didn't like them and ended up redoing the front in rubber. Have never gotten around to removing them from the rear. Prothane used a silicon grease, which they referred to as "whale snot" for lubing their bushings. Like Mikey, bad mistake on my part.
 

Hib Halverson

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My experience with urethane bushings has been mixed.

They both reduce compliance in the suspension (good for limit handling) and increase noise and harshness (bad for ride) because their material has a much higher durometer.

Urethane bushings tend to squeak in damp weather. The only ones I've used which don't squeak are the graphite-impregnated urethane units sold by some vendors.

The bushings I have in my C3 now are Global West "Del-a-Lum" type which are more of a suspension bearing than a bushing. Del-a-Lums are even stiffer than urethane so they are totally a handling-oriented part but...they never squeak and will outlast just about everything else...rubber, urethane and spherical bearings.
 

Antz81

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They are the single worst thing I ever did to my car by far and I truly regret downgrading the vehicle with them.

When I did all of my bushings I did a little research on what people thought of them and this sums up what I found in one sentence.
I asked the local corvette parts guy what he thought of them as well. He said he could get them if I wanted them, but he wouldn't recommend it. He stocks rubber bushings but not any of the polyurethane bushings.
I decided rubber was the way to go, and I'll do the same next time.
 

kpic

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One of the young engineers where I used to work bought a 99 C5, a FRC as they are stiffer than the coupe or vert. Then he set it up for auto-crossing. He invested a lot of money, time and work to make it more competitive.
All I can say is not for me.





 
Joined
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Yemen
From an engineering standpoint the polyurethane design is much better than the OEM design because rubber bushings aren't designed to be twisted; just designed for shock loading. If these bushings hold up to a continuous loading without crumbling they should work great. Time will tell.

In looking things over I can already see it's going to be a big job because I seem to remember tack-welding the left/rear control arm stud. If I did the left exhaust manifold will have to be removed along with the water pump, fan, fan shroud, and the A/C compressor will have to be loosened and pulled out of the way. I'll do the installation during the night time and early morning hours to avoid the 100+ degree day time heat.
 

Vettehead Mikey

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From an engineering standpoint the polyurethane design is much better than the OEM design because rubber bushings aren't designed to be twisted;

On the contrary- that's exactly what they were designed to do and why every OEM in the world (save one) chooses to use them as a captured-style bushing. A brilliant but simple method of incorporating variable rate deflection compliance vs. single rate. You're also softening the effective spring rate at each wheel by going for a sliding bushing.

You are obviously unaware of these critical functions and are about to downgrade your car with sloppy single rate blocks of hard plastic. Nice. That's quite an ego you've got going thinking you're smarter than all OEMs.
 

kpic

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From an engineering standpoint the polyurethane design is much better than the OEM design because rubber bushings aren't designed to be twisted; just designed for shock loading. If these bushings hold up to a continuous loading without crumbling they should work great. Time will tell.

No, polyurethane bushings are designed for different purposes. There are always trade offs or the only free cheese is in a mousetrap and usually only free for the second mouse.

Rubber v Polyurethane Suspension Bushings - AftermarketSuspensionParts.com
 

GTR1999

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I haven't used them in the arms and would not in the trailing arms but have them for motor mount and trans mounts in my mild 72 cruiser. We ran poly mounts in my sons car and they failed in that application in no time. He is running solids mounts and a full cage now, stiff vibration city is what I call the car now. I stick with rubber when rebuilding arms for vettes and so far haven't had a complaint.

100k miles on them and you had to replace them? I can't say I've ever put that many miles on any of my vettes so I can't compare them but the ones I replaced were off 100k+ cars for guys so maybe that is the life of them, I don't know. I have 230k on my original S10 and they are still good!
 

Vettehead Mikey

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Antz81

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I haven't used them in the arms and would not in the trailing arms

When I was first doing my research on this one of the biggest reasons not to use poly in the trailing arms was that the arm doesn't move on just one axis. The rubber can allow for this where the poly being harder resists the movement, from what I found those that had used poly where replacing them due to failure far sooner than those with rubber.
 

kpic

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Interesting comparison, but like most similar articles, it completely glosses over the advantages of a captured rubber bushing when put in torsion.

Typically most online articles aren't written by suspension engineers. As I'm old, I'm slow. Torsion is a twisting moment, correct?
 

Vettehead Mikey

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Correct. The applicable analogy here would be taking a wet towel and wringing it out by twisting the ends. It's limp and flexible while at rest but hard and rigid once twisted. The rubber in a bushing reacts the same way when the suspension member is deflected.

The difference in hardness between poly and rubber in torsion is negligible.
 
Joined
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Well, I'll find out just how good they are because I'm going to start the installation early tomorrow morning. It's only the upper/rear that failed because they squashed flat and spit a big gob of rubber out. I know various grades of thermoplastics have replaced the bronze alloys in many applications so this will be an interesting test. I like the idea of them actually rotating rather than torquing because rubber doesn't withstand torquing very well.
 
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I actually thought, before opening your post, that you were going to trash them like you have with headers and double pumper carbs.


I never "trashed" headers or double pumpers. I merely stated they aren't suitable for street engines that operate at much lower loads and rpm levels than track racing engines. Same goes with 360 degree single plane intake manifolds and the use of long duration track racing camshafts that are intended for 4000+ rpm continuous use. If you want to learn which parts are intended for street engines look at the components the factories used in their muscle cars.
 

Vettehead Mikey

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because rubber doesn't withstand torquing very well.

No, except that hundreds of million of cars have been built with them and there's no real evidence that there's a problem with unacceptably low durability. You'll find the average car that's gone to the great scrap yard in the sky still has it's original bushings while the ca around it fell apart.

If you did your research properly you'd also find that a lot of poly enthusiasts are finding that their favourite bushing also doesn't last forever. They typically fall apart in big chunks, sometimes without warning.

Kinda like this:
347045d1238087428-weltmeister-poly-bushings-bushing3.jpg
 
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Different Material

As it's so damned hot here I am pacing myself..............working in the cooler morning hours and resting during the day when it's HOT. I have my new bushings sitting in front of my keyboard and just discovered the upper bushings are a LOT harder than the lower bushings. About twice as hard using my fingers as uh "crush meters". And the upper bushings have a very shiny appearance whereas the lower bushings have a very dull appearance.

I am having to remove my left exhaust manifold because the rear control arm/shim bolt had been tack-welded when I put new bushings in 5-6 years ago. No big deal as it's almost off. Early tomorrow morning I'll get the manifold and control arm off and I should get the left side back together by noon. Then I'll rip into the right side and that should go a lot faster because I already have the radiator mount loosened and the fan shroud removed.

I found the lower bushings had also squashed quite a bit so I'm glad I bought the whole set. Now I'm just hoping they'll perform better than the OEM/MOOG style.
 
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Replacing Upper And Lower Control Arm Bushings

I got the left side done and the right side half done. Because of severe pain and this dreaded heat I can only work about 5-6 hours in the early morning hours. I should get the right side done tomorrow morning and then I can start putting everything else back together. And then I can do the front end alignment using my tool and digital angle finder.

These polyurethane bushings are pretty slick but I'm hoping they last longer than the OEM style. As always I'll log the repair and mileage in my record book and then keep a watchful eye on them.
 

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