I'm rebuilding the rear suspension on the car, since I pulled the rear differential. I am not sure yet if I want to go with the standard rubber bushings or the poly ones. Any advice? I am thinking rubber since Thats what I just did the front suspension in.

 

If you just did the front with rubber...I would stick with rubber in the back too...just to be consistant.

 

For the rear, the trailing arms bushings should be rubber. This is a moving bushing and it has been proven that rubber is a better design for this location.

As for the pumpkin mounting, poly is a good choice as it helps to stabilize this non moving part.

This is how I set-up my 82.

 

Ideal for the street. Poly bushings are a compromise as bearings, and that's exactly what control arm bushings and trailing arm bushings are. Poly works fine for sway bar end links, "puck" mounts like the nose of the differential, and for mounting the (monoleaf) spring- although rubber is fine there too.

 

I used rubber for the t-arms and poly everywhere else.

 

The correct question is, "rubber or heim-joints & sphericals?" Poly is fine for bushing applications (i.e. anti-roll bars, CA's...) where designed suspension movements are in one plane, but IMCO it isn't best suited for those where movements are inherently 3D, such as is the case with rear TA's and camber struts, as torques and binding "stiction" can become more significant issues.

But, the bottom line is that I wouldn't bother with anything but rubber out back if that's what you have up front..


TSW

 

Thanks guys. I'm going to order my kit today

 

OK... now I'm slightly alarmed. I just got a complete car poly kit.

What am I up against?

-W

 

I can give you list of guys (including myself) that have installed poly in the rear and have had no problems. I understand the dynamics of why rubber is better, and have looked at the movement(s) and plane of the t/a's. And there is lots of reasons why both the rubber AND the poly need to be tossed and real joints installed. There are people on all sides of this one. And all came prepared with valid arguments. When I did my 69, I went so far as to cut lube grooves in the ID of the bushings, then drilled the shells and installed grease fittings so I could lube them if they started squeaking. So far the lube I used when I did the initial install is fine. No squeaks.

 

Don't even consider puting poly in the trailing arm, everywhere else fine in the rear suspension, but if your kit came with poly for the traling arm
forget you got them go buy a set of rubber trailing arm bushings.

 

That's really odd. I have been installing bushings in Corvettes for over 20+ years. MANY of these cars are come in for routine check-ups and repairs. I have never had one problem with polyurethane bushings. Not one. And I'm not talking about one or two cars either. I wrote MANY (20-30+). I take a close look at all areas because most of these cars are drivers and not trailer queens. And yes many of these cars are rubber bushed cars also.

I have not had ONE complaint dealing with adverse handling or noise from the poly bushings. IF anything, they LOVE the way that they have control while driving.

I understand the dynamics of the motion of the trailing arm. And when you are dealing with cars that have very close to if not correct factory tolerances, (i.e. rear wheel bearings and side yoke rear differential run-out)

I need for someone to send me detailed info on the damages that can occur by using poly t/a bushings along with the strut rods.

I am in no way saying that anyone writing that having poly t/a, strut rod bushing is wrong. I just need to see the evidence thet says that it is...thats all. Becasue on my end , I haven't seen any ill effects.........yet. And around here, the roads are not straight for long. Curves and hills galore.

I have clearly seen over the years on what the rubber bushings look like. Like many of us have who have replaced them. And the rear wheel bearings, and side yokes usually also need replacing due to wear.

Clams Canino:
The only issue that I have with the VB&P t/a bushings (if that is what you have) is that when installed they wider than factory. This added width takes out shims, and now can cause the toe setting to not be achieved, (like has happened to me on a few cars, not all of them). This is because the added width reduces the amount of movement the t/a needs for possible toe alignment. SOMETIMES causing the bushing to contact the inner "pocket" where the t/a is connected, and still needs further movement to achieve correct toe. I switched to another manufacturer that has correct dimension bushings that look just like factory but have poly instead of rubber. AND still require the correct staking tool to install.

I gladly accect any documented credible information on this issue that I stated above. This information can also include the trailing arm "dog bones" for a 1984-1996, which also can be installed with poly.

I always strive to achieve high standards for my customers. And if this information I get can PROVE that POLY is no good. Myself and my customers will thank you. This is one of four areas that I am a "stickler" over. SUSPENSION. The others are BRAKES, FUEL SYSTEM and STEERING.

Gladly waiting for a response.
"DUB"

 

Theres a lot of slop in the rear suspension poly can get rid of a lot of the problems for a street car, good quality spherical ends in the strut rods would even be better. rubber should be in the trailing arms, unless you want an expensive spherical bushing. a simple rubber bushing can deflect or twist in two directions, poly can't.

later C4s don't have the problem in the trailing arm the early IRS has.

 

I would also like to see some data on why poly shouldn't be used for the trailing arms. I use it everywhere in my car to eliminate as much of the slop in the suspenision as possible. Where I don't use poly is in the end links of the front sway bar. Poly caused my car to push on corner entry. I found the front needs to move a small amount before the sway bar takes over.

 

Well hopefully I'm not one of those "few".
I have no idea of the brand of bushings. The kit I ordered is the $1199 package deal "total suspension kit" from Zip Corvette that comes with springs and all. I think I'll be OK with the wider bushings as I have every reason to believe that I have factory shims in there, and they are about equel width on *both* sides of each arm. So *if* correct is still near the middle on that car - it'll be easily OK.

I'm curious with what and how you'd like to see me lubricate the t/a bolt and bushing arera on re-install. (assuming I can ever cut them out).

-W

 

Rubber can twist in two directions at the same time. Poly can only rotate its good to eliminate deflection lots of good places it can be used.

The front control arms factory rubber just twists , if poly is used it rotates instead of twisting. This is all in one direction the wheel moves up or down everything is in one direction even when body roll enters the picture all the movement is in the same direction, poly works here it will rotate in one direction gets rid of the rubber deflection.

The trailing arms are nothing like the front control arms they are running parallel to the frame. The bushing in the front of the trailing arm needs to be able to move in two directions at the same time, one direction for the up and down movement of the wheel, another flexability of movement in a different direction when body roll enters the picture. A rubber bushing can do this be twisted on in two directions at the same time, a poly bushing does not twist it can only rotate in one direction.

You either use factory rubber or a spherical bushing both can move in two different directions in the trailing arm.

You sure don't want rubber in front control arms or strut camber rods if your after best handling.

 

I'm good with the up/down movement - but I never like to encourage or enable body roll anyway. So long as they go up and down I'm happy. And if they tend to thwart body roll - all the better.

-W (a nights sleep adds clarity to many things)

 

I was under the assumption that they are not good at bending 2 ways at once and because there harder they end up cracking or splitting in two. So I could see in being in the trailing arm the immense pressure could damage them. As rubber would just bend.

Although I have never seen one crack in person. But all the rubber ones I put on my front shocks are split and look like there 25 years old and I put them in about 3 years ago.

 

Your missing the point without the movement allowed your creating binding in the suspension you don't want that. How stiff you choose to go with springs controls how much body roll.

 

I 've done quite a few vettes with poly and never had an issue, I also did mine an 80 this spring and I'm real happy with the poly bushings, but I can see a point on the control arms and trailing arms! Ron

 

No reason to not use poly anywhere else but the front trailing arm bushing. wheathering does not effect them they stiffen everything up. For someone that never pushes there car for cornering just uses it as a cruiser rubber up in the control arms isolates the shock to the frame better, theres a ton of slop in the both ends of the strut camber rods with rubber at both ends, Its a win win deal using poly over rubber there.