I just ordered a set of SuperPro bushings from C&S Corvette for my 1984 base model. I've heard many manufacturers and suppliers say polyurethane bushings go bad over time -- that they either deform plasticly or just disintegrate completely all of a sudden. I'm looking at other SuperPro products, and they're 3 times as expensive as equivalent ProThane bushings. I've also heard people say that poly bushings can last a lifetime, so where does the truth lie? Are urethane or polyurethane bushings really a lifetime product or are they a lower quality product that in time will leave me with an even worse ride than before? I tend to think that most claims are marketing b.s., so I wanted to see if any of you have firsthand experience with polyurethane bushings. Bestow me with your wisdom, if you will.

 

In my experience they last a long time in a single axis use but deform and take like a dent in two or three axis uses. For example they are great in the a arm but bad in the sway bar end link.

I've only used energy suspension, pro thane, super pro, and not no name or low quality product so I can't speak to that.

 

Thanks! So, does that mean they'd do well as differential carrier (batwing) bushings? Or do these get torsional deflection under drive train load?

 

The ones I've had for the diff are really tough and haven't seen a problem with them.

 

Solid Delrin is a better material in the bat wings and front control arms... however, it does induce harshness and noise compared to SperPro. Urethane in general (not so much SuperPro) cold flows, has very high friction even with lube, I hate urethane to be honest. The Batwings are about the only place I would use them on a C4. Never had problems with SuperPro, they seem to be softer and more resiliant, and the lube works well, but I've since replaced all of it with delrin or high quality Heim joints.

SuperPro is probably the best product for street/comfortable use, I would guess they last a long time if lubed every few years or every 10K miles.

 

@AZSP33D Where did you find the Delrin batwing bushings?

 

stock is easy to come buy and it takes about 20 minutes on the manual lathe. I wonder if someone would have them but I haven't seen any.

 

Can Steel has some solid aluminum bat wing bushings.


But yes, poly can distort and break down. I’ve seen it mainly on swaybar mounts, but also in lower front A-Arm and also in the rear.

 

Hello:
My experience has been that the Poly Bushings are not very well made - especially with respect to tolerances.
I ran into this problem years ago when installing Poly bushings in the front upper and lower control arms of a C3 Corvette. I bought an expensive set and I found that after following all the correct procedures for installing them, the bind the suspension had was terrible.
You can also watch a YouTube video on this very matter from a gent in Australia. Just do a search for the following by Andy Walker:

Aussie 84 Corvette 434sbc SuperPro Bushings

His video really sums up my experience well.
Personally I would never entertain a Poly bushing ever again. You really do get what you pay for. Ask yourself how much time and money are you spending if you have to do the installation over again?

My first choice for keeping with stock suspension parts is to use Delrin bushings. They are harder and will transmit more road noise however they are awesome for high performance cornering - which is why I like them so much.
My second choice is to use the SuperPro bushings. They offer ease of movement on both single and multiple planes which is a requirement for the C4 rear suspension, and they are also quiet.
If you are building a cornering machine then spherical rod ends are the only way to go but this requires all new suspension components and may be cost prohibitive.

I have not run solid aluminum bushings yet, however if I was going to do that the Batwing would be the place I would do it - HOWEVER the road noise would likely be terrible. Another drawback is that you need to remove the steel bushing shells from the Batwing, so the installation and reversal if you can't stand the noise is going to be much more difficult.
Aluminum Batwing bushings are available at VanSteel as mentioned by CV.



I hope this helps you in deciding which bushing to run in your C4.

Best regards,
Mr. Bear

 

That's surprising, since sway bar links are only stressed axially.

 

Send me the dimensions and I'll make a set for you.
On my manual lathe, it will take about 20 minutes each........