NMT1957

Im doing a complete restoration on a 69 427/400. Im looking for opinions on rubber vs. polyurethane suspension parts. I hear the polyurethane is "better" but the rubber gives a much softer ride. Im not going for NCRS but I do want the original look. Appreciate any opinions.

GDaina

It all depends how you want the ride...you have solid aluminum body mounts, and as it is, you have a harsh ride as it it. With the poly bushings, expect even a harsher ride.

Taijutsu

Use Poly in the suspension to minimise deflection. Use rubber to mount body to reduce vibration and add flex for fiberglass. JMHO

Ricisan

capevettes

I would stick with the rubber. They will last a very long time and look correct. The poly ride very poorly. If you were building a track type car I would go with the poly. I have had to make this decision a few times and never regretted going rubber. A 69 400 horse is a car worth keeping correct. Just my opinion

SanDiegoPaul

Use Rubber...

GDaina

there are pros and cons using poly and rubber...rubber will last 30 plus years, at least mine did....replaced the body mounts with rubber and control arm bushings with rubber...decision I will never regret doing..

another-user

i went with all poly in my rear end rebuild last year. its a very smooth ride. no regrets about going all poly. im doing the front end in all poly this winter.

redman76

I did poly on the front last year with stock suspension . . . really helped tighen things up. Smooth and quiet! Have poly for the rear suspension that will be going in the next month or so.

jb78L-82

I agree with those above who recommend rubber for body mounts and poly everywhere else. I have poly upper and lower control arm bushings, poly sway bar mounting and end link bushings, and poly on the piston arm for the steering shock, and even poly bushings on the front heavy duty Bilstein shocks. In the rear I have poly bushings on the rear compositie spring end bolts, rear 3/4 in OEM type sway bar, and until very recently, the rear strut rods (I switched to competition struts with the heim joints). The car is so much tighter than the rubber bushings and rides terrific. No squeaks from the control arms. I would never use rubber on these components again purely from a performance and ride quality issue. The car rode so much looser with rubber bushings especially in the control arms and rear strut rods. Setup correctly you can have a tight firm ride (not uncomfortable, at all) and much better steering and handling!

Nemesis_152

to be completely fair, though, you went from 30 year old rubber to 30 day old poly bushings. not exactly a fair comparison.



that said, my 75 is in the middle of a full polyurethane rebuild.

jb78L-82

Not exactly. All the changes mentioned above were done separately (Control arm bushings 2 years ago, Strut rod bushings 25 years ago, Front sway bar bushings 25 years ago, rear sway bar and bushings 5 years ago, front shock mounting bushings 2 years ago). Nothing at same time, always one at a time so I can gauge the changes.

TimAT

I put poly everywhere- even the T/A's and lot's of guys recommend against that. I did, however, cut grooves, drilled, and installed grease fittings in all of the control arm bushings in case it ever started squeaking.

Nemesis_152

oh, ok. as you were, then

thegazman

When I rebuilt my 79 front end I used poly everywhere. Steering is very positive, but I feel every bump in the road. If I had to do it over I think I would use rubber.

stock76

I used polyurethane control arm and sway bar bushings. One of the upper control arm bolts walked out. Fortunately I was going about 5 mph and turning in to my driverway. Still, a scary event. If you go poly on your control arm bushings makes sure to use red loctite on all bolts. Mine are now starting to squeak a little after 2yrs. The 30+ old rubber ones never made a sound.

I also used poly on the spring bolt cushions. Two of them developed cracks and one just crumbled in pieces. Replaced those with rubber and have not had any problems since.

Personally, I'll never go poly again. There was a reason GM engineers chose rubber and not polyurethane as the material of choice for those components.

PeteZO6

Before you decide to use poly bushings, consider this: The best handling Corvettes in the modern, or any era, the C6 Z51, ZO6, and ZR1 all use rubber bushings in the suspension.

As my sig. shows, I have an '07 and it will rail through turns like you wouldn't believe. In the interest in not overly stressing the body on my '69, I went with rubber bushings in the front suspension. Since it's a convertible, with less body rigidity than a t-top, that seemed to be the best way to go.

NMT1957

Well, thanks for all the great information. I think Im going with all rubber for several reasons. I prefer to stay correct on a 427/400 car, the ride has to be smoother, and if it lasts another 30 years Ill be wearing a diaper so I wont feel the bumps anyway. Thanks, Ill be looking for more opinions as the restoration continues.

jb78L-82

No question that the modern era vettes use rubber instead of poly because the suspension designs and tire technology enable a much higher level of performance than was possible with C3's in their day. If one is looking for much more up to date modern performance on their C3 than poly will go a long way to achieving the goal. Setup up correctly and installed correctly, poly bushings will not squeak, crack, or deteriorate as quickly as rubber. They also will ride surpisingly well. Poly bushings were not used on the C3's in their day because poly technology was in its infancy at the time C3's were built and designed. As an FYI, many state and local police cruisers in the late 80's and 90's especially the crown Vics came from the factory with poly upper and lower control arms for added control, steering response, and longevity, pretty good endorsement for poly technology.

PS Have been using Poly bushings on my C3 at various times and just about every suspension component for 25 years and have never replaced one yet nor have I ever had one go bad. I did have a control arm bushing loosen up since I did not torque the bolt correctly. I check everything annually for safety!

70ZZ3 96LT4

I think you made the right decision to use rubber bushings. I have poly in my 68 and 70 that I installed.