shft22

:ran t:

The first thing I changed on the car after I got it was all the bushing, this was back on 2003. I purchased a complete suspension kit from VBP front and rear and every bushing was polyurethane, the trail arm was also rebuild. This car has not driven much since, between engine, transmission, interior, differential work, new house and kids it has spend many months in the garage, so I will guess less than 3K miles since the new suspension. Well this morning took her for a drive and on the way back the rear felt lose, the rear will actually steer while transitioning from gas to break.
Got her up on jack stands as soon as I got home and the right side trail arm bushing is gone, so looking closely, the spring, trailing arms and front sway bar bushing are disintegrating , they are hard and if you touch them they become like dirt and fall apart...
Whats the life expectancy of these things??

Man I really don't feel like taking the suspension apart, bad timing beautiful weather for drives is finally here....

mrichard

I have had the same experience on a car I outfitted with Poly-U. After doing a little research I found out that heat, Ozone, and good old sunshine mean death for Poly-U. Imagine this... I was using a Poly-U dead blow hammer on my Avalanche one day and left it lying in the Colorado sun while I went in the house for lunch. When I returned the hammer had melted on the driveway. Go figure that. Anyway, I will never never-ever use Poly-U on anything on my cars. Especially motor mounts and body mounts. This is just my experience, your mileage may vary as usual. There is an ingredient the mfg. can add to slow down the ozone effect which is the same as in any plastic from what my P.E.T. manufacturing friends tell me.
Mike Richardson P.E.

JohnZ

Poly bushings for normal suspension applications on a street-driven car where the bushings are stressed are a recipe for unhappiness; they're ill-engineered for those applications, and are peddled based on marketing hype and kindergarten-level engineering.

Replace them with the correct OEM rubber bushings (you'll need special tools to properly install the trailing arm pivot bushings, as noted in the Chassis Service Manual), and you'll never need to touch them again.

65Bob-bo

The're junk on trailing arms. My black polys came apart after a few years of weekend driving. Still have polys on front and rear suspension. Went back w/ rubber for t arms.
Bob

4 Speed Dave

The VBP poly kits use Prothane (sp) poly bushings. I have used Energry suspension bushings on my Nova, Jeep Cherokee, a 98 1 ton dually and never had any one of those bushings fail. I have read about the Prothane bushings failing. I also am using them on them 66 I am doing now.

As stated above I have used Energy Suspensions in many applications and they work very well and so help with handling. THe most noticable was the improved handling on my dually. To say they don't belong on daily driven cars is simply not true.

Grouping all Poly bushings as being bad is not accurate.

63split63

When I purchased my LT1 it had all polly in the front suspension. They were not falling apart but they were rock hard, rattleded and squeaked terribly .
I took them all out and replaced them with OEM .

Bill

Bluestripe67

I have had the VB&S poly bushings in all places on my '67 since '99, and that equals about 34K-37K miles...zero issues/problems. I'm all over my car for preventative maintenance on a very frequent basis. Rubber bushings will dry out. Dennis

6T7L71CPE

Same here, I'm Un-doing "improvements"! too. I didn't have the cups on the spring bushings but I still think they would have cracked as did the strut and trailing arm bushings. Fronts aren't cracking, just creak like my knee joints! These are 20 year old VBP bushings but low mileage, always garaged.

Frankie the Fink

Ouch I ran poly all round on my autocrossed Shelby-ized '66 Mustang but had no illusions about the exaggerated benefits for normal street use. My '61 got rubber across-the-board and it rides phenomenally (for a C1 anyway)

TheSaint

I thought that the poly kit was supposed to last for 20 years

I bought a total suspension kit but i have only used them on the the end bushings on the front sway bar

For other bushings i have used original rubber bushings

It is a kit like the one on the picture i bought a few years back

Mr. Wizzard

I've run the black Prothane bushings on my Honda's since 2000. I've beat the hell out of the cars, and during the day, they are parked outside. Since the cars serve as test vehicles for all sorts of engine componentry we make, they see frequent inspection. I have yet to see any issues with any of the bushings...including the rear trailing arm pivots, which we drilled holes in to allow more off-axis flexation.
Granted, we don't see much freezing weather here in Ft. Worth, but the summers are HOT.
We use the proper marine grease when installing them and they don't make any noise.
I've configured most of the suspension on my Grand Sport replica with Prothane bushings, and I don't expect to see any problems.

JohnZ

The problem with poly bushings is that they MOVE/SLIDE/ROTATE relative to the parts they attach; they either rotate in the outer shell pressed into the part (or in the O.D. of the hole in the part if there's no shell), or their I.D. rotates on the shaft or on the through-bolt joining the parts, or both. This relative movement between the parts eventually leads to wear, noise, and deterioration between the moving parts.

OEM rubber bushings have ZERO movement between ANY of the parts. The steel outer sleeve is pressed into the control arm and doesn't move, the inner steel sleeve has serrations on both ends that are locked in place between the step on the shaft and the bushing bolt and retainer so it doesn't move, and the rubber portion of the bushing is bonded permanently to the I.D. of the steel outer sleeve and to the O.D. of the steel inner sleeve. Movement of the control arm is managed 100% by deflection of the rubber within the bushing element, which is why they're installed with the suspension at design ride height before torquing the through-bolts so there's zero torsional stress on the rubber element unless the suspension is moving in jounce or rebound. The compliance within the rubber element absorbs ride harshness, depending on its durometer. Sketch below shows a section through a typical OEM bonded steel/rubber bushing.

The I.D. and O.D. of Poly bushings move constantly relative to the parts they join, and their extremely high durometer transmits road shock and ride harshness directly into the frame; they're fine for racing, autocross, etc., but require lubrication and maintenance and are a poor substitute for the OEM rubber bushings that never need any attention at all while providing reasonable ride harshness isolation in a normal street-driven car.

Bluestripe67

I guess some of us, including Bubba, are satisfied and comfortable with kindergarten level engineering. After all, some of our cars are NCRS, N=NOT, C=Correctly, R=Restored, S=Stingray. To each their own. Dennis

ejboyd5

50+ years later we still find that the Chevrolet engineers really knew what they were doing.

biggd

I always use silicone based lubricant when installing bushings. Works great and prevents wear and squeeks.

jim lockwood

When you want to be really,really impressed with the engineering sophistication of 50+ years ago, study the operating principles behind Rochester fuel injection.

It is absolutely amazing that a lump of metal with no computers, no electronics, no closed-loop feedback, and not even a direct connection between throttle and fuel delivery can so accurately meter fuel over such a broad range of operating conditions.

It's a mighty impressive piece of work.

Jim

4 Speed Dave

So what grade level are Global West bushings? Must be at least second grade. Part of what John said is why I don't like the rubber OEM bushings. They resist rotation and don't allow the suspension to move freely. THus the bushings and the shocks are dampening the suspension instead of the shock doing all of the dampening and controling the movement. I have Globabl West bushings on my Nova now and they are allow the suspension to move very freely.

For most people the OEM bushings are fine. But there are other alternatives that can be used.

Plasticman

Gee, maybe someone should market solid steel bushings for the C2 (like the solid axle Vettes).

Work great, as long as they are greased every 1K miles.........

Plasticman

Mike Ward

That's actually one of the positive design features of a rubber bushing. It actually doesn't dampen the suspension like a shock, it resists compression like a rising rate spring. All part of the overall design that gets lost when poly is used

Two other great features that John didn't mention

1) the compressibility of the rubber decreases as torsion is applied to the bushing, another example of rising rate compliance. This means that road shocks and vibration are damped out with the suspension at a neutral setting while cruising on the highway and the bushing become rock hard while under maximum deflection under heavy cornering. Poly has the disadvantage of being rock hard all the time

2) many suspension joints on a C2/C3 require movement in two or three dimensions, notably on the front of the trailing arms and both ends of the lower strut rods. Poly is incapable of allowing such movement unless it is made softer which defeats the the whole premise. The so-called adjustable 'smart struts' are well known to come loose at the jamb nuts due to the inflexibility of the poly bushings.


I wish I had realized all this stuff before I put the da*n things on my car.

4 Speed Dave

That is why I used spherical rod ends on my rear suspension.
To each their own I'm done.