I just changed all my OEM bushings in rear( haven't done the front yet), and installed the new poly bushings. (80,000 miles)
Now it rides like a piece of crap lumber wagon. I feel every bump every pebble and crack in the road. It just ruined the ride of my C4. I'm seriously thinking about NOT changing the front bushings.
Has anyone else experienced this.
Anyone have any thoughts in the matter?

 

 

Yes I got a wheel alignment just to be on the safe side. My markings were spot on.
However it didn't help with the rough ride. it ride like a Ford Fiesta now.
Maybe I need to o down a rough gravel road and soften up those hard poly bushings. lol

 

Alignment has nothing to do with ride quality. In a C4 especially, the occupants sit almost on top of the rear axle. So the rear compliance has by far the bigger influence on ride quality. If you changed the batwing bushings, that would have the biggest effect on ride quality, I think. I'm not a fan of poly bushings in the rear of a C4, because they cause bind due to the fact that the camber rods and the trailing arms move in more than one plane. I don't know if that's what you're feeling vs other issues, but if you didn't change the batwing bushings, then it's probably the most likely explanation.

 

When I changed my rear bushings to polyurethane my car rode smoother. And my shock absorber damping rates needed to be changed.
Curious, did you remove the sway bar?
If you did is it possible you installed it upside down?
I did this once by accident and the car rode like a buck board.

 

I know that alignment has nothing to do with the ride, However I wanted to have it checked to be sure.
No I did not remove the sway bar. I did one side at a time because I was not in a situation where I could do a complete tear down.
This is just my assumption, but I think I was use to the old ride with the worn out bushing and didn't realize how it should ride with a tight suspension.

 

 

 

..... I see a mini-van in your future …..

 

 

Did you change tire pressures at all while you had them off? With our lousy roads, if I run anything over 30 psi, it's like riding on a skateboard.

 

I installed Polyurethane Bushings on my C3 and on my C4 and I wish I had not done it in the first place. Your ride should get better as things get bedded down in your suspension. After about 500 miles my Corvette started to ride better. You might try putting some lubricant on them to see if that helps. What kind of shocks are you using?

My biggest complaint is that when I did my bushings 20 years ago they did not have graphite built in like the newer bushings do. My cars both squeak like crazy in the cooler weather so I squirt dry lube Teflon or silicone into the joints about once a year usually in the spring.

My C3 rides the stiffest but it has a lot to do with being originally a L-71 Corvette. I have KYB gas shocks on my C3 and I can tell heads or tails on a coin when I run it over, it can be brutal. Time for a better shock for me.

After all of my experiences I would hesitate to call the switch to poly bushings an "upgrade". Next time I will use plain old rubber as these bones are getting older and don't like the buck-board ride that I was stuck with after the install.

Merry Christmas and Happy New Year with your Corvette!
Chris

 

Unfortunately you can't buy rubber bushings for the camber arms or trailing arms anymore.

 

look here
https://www.corvettepartscenter.com/collections/c4/products/late-1988-1996-corvette-suspension-bushing-kit

 

Yep, I was going to mention those but couldn't recall the name, and then got sidetracked. They aren't rubber, but they do appear to be more elastic than poly. Those appear, probably, to be the best option for the rear suspension bushings other than rod ends. I say "probably" because without actually testing one we don't know how much out-of-axis movement they allow without a lot of force. That is, we don't know how much they will bind as the travels through its arcs. The stock rubber bushings don't have much bind, rod ends have none, and poly has a lot. I would be interested to take a dog bone with each type of axial bushing (rubber, poly, and Super Pro) and do a test of deflection rates: chuck each in a vice and see how much force is required to twist the rod and move it laterally a certain amount. But anyway, yes I think these Super Pro bushings are the route I would take for the rear suspension of a street C4, or even for a race C4 that didn't allow rod ends.

 

I changed both ends of my 84 to the poly bushings and yes the ride is not like it was before. I like the difference personally. It did change for the better after I got some miles on it. The original bushing were mush when I removed them. I would do the change again in a heartbeat compared to what it was before the replacement.

 

there is a video out on youtube that shows how to install them. I told the forum here about them weeks ago, if you go down to post nbr 4, I included the link to the video. run it full screen and watch the compliance when the bushings are put into the dogbones

https://www.corvetteforum.com/forums...-bushings.html

these are what I am going to buy as I restore the Dana 44 I am putting in my car.

https://corvettesalvage.com/product/...set-1984-1996/

 

I've seen that video, I think as a result of reading that post of yours. These are definitely the best option out there for the rear bushings in a C4 short of rod ends. They are good for the whole car if competition isn't in the cards.

 

As I mentioned, I am going to get the ones for the batwing. I have a set of the poly ones, but the more I read about them, the more I dislike polyurethane.

It is just as you and I (M.M.) discussed the rod end sway bar links, but I will have to study the motion. Those pin top shock mounts utilize a rigid bushing, however, that forces the motion soley into the shock, there is not a piece of rubber squishing before the shock starts to move.

Back when I had the 65, there was still OEM bushings available for it, due to the commonality of parts between the C2's and C3's. I ripped the suspension out and rebuilt it back to factory new and it road superbly.

With the batwing bushings, with either the oem rubber (when it is still compliant) and these new bushings, there is going to be a bit of movement/deflection, but how much ?? I guess how well they are encapsulated will affect them.

I have the beam plates from ZFDoc that I am going to install when I put the D44 in. Those should definitely firm up the c-beam/trans/diff interface and limit some of the movement, so I am hoping that these new bushings will help soak up some vibration but not allow too much deflection.

I can "feel" when a car is not tracking true and it drives me nuts. Very often I have my wife (or son) follow me to see if a vehicle is dog tracking. That is how it feels to me if a car (or truck) is not applying force straight through the middle of the vehicle. There was a specialty alignment shop in the area when I younger (actually still is there). The owner at that time raced, so he understood when I had my alignments set at "even even" and lived with the drift from the crown of the road.

HOWEVER I do agree that for racing purposes, some custom machined and fitted Del-alum bushings would tie it up tight.

I am really looking forward to driving my car when I get all the new suspension pieces in.

Go back in time and revisit this post that Tom put up. (another spot on post for that matter).

https://www.corvetteforum.com/forums...al-member.html

there are a bunch of different points presented in it, I suggest everyone in this thread go back and reread it.

like some of the folks that talked about the beam plates in the thread, I bought them to help spread the clamping load across the aluminum and not let the bolt holes hog out.

one point that I found terribly interesting was the the C4 was originally intended to have a torque tube, but certain difficulties caused it to be delayed until usage in the C5's,

the heim joint suspension that I am putting in (Banski Motorsports) is going to limit the amount of twisting going through the batwing bushings, so as I envision it, the movement is going to be mostly up and down, hence a little cushioning effect not transferring so much road vibration into the car.

Here is a really good read on a C4 suspension rebuild.

https://tech.corvettecentral.com/201...sion-overview/

https://tech.corvettecentral.com/201...shing-service/

https://tech.corvettecentral.com/201...-installation/

 

The two types of movement the batwing is preventing are: 1) rotation around the central driveshaft caused by drivetrain torque at the pinion gear (the diff is trying to rotate around the pinion in reaction to the driveshaft torque), and 2) lateral movement caused by cornering forces (because the lateral links are connected to the diff/batwing). Of the two, I'm sure #1 is the far greater force, and it would get much greater with tires that can hook up better than normal street radials (i.e. drag slicks especially). And that's why the batwing's "span" is so wide: to give it as much leverage over the torque as possible. It would be interesting to mount a camera under there to see how much movement in those bushings really takes place with new bushings of whatever type. I still have OE rubber in mine, but they're in good shape with only 56k miles and a car that's always been garaged. If those bushings wear out, I can imagine things get ugly.

I use those too. I mainly got them to make removing and installing the bolts easier. If they help with some added clamping force, so much the better. I'm not sure if that happens or not. I think that to actually increase the clamping force, you'd have to torque the bolts to a higher value. But those plates should allow that since they won't have washers digging into soft aluminum, because they can spread that force over a wider area.

That was interesting, yeah. I hadn't read it, since it was before my time in this forum. Thanks for that and those other links, too.