I've got an 84 with 121k on it and what appears to be original suspension. I replaced the shocks and recently had to replace the rack and pinion and tie rod ends. Next on the chopping block are the control arm ball joints as they're quite worn. I've noticed that the rubber control arm bushings are pretty cracked, but I'm not sure what indicates that they need to be replaced. I understand that pretty much the only option is to replace with poly bushings and that they may be a little squeakier.

My questions are, since I'm in this deep, should I go ahead and replace the control arm bushings while I'm at it? What would indicate a need for replacement? I've read that poly bushings require regular disassembly to grease them, is that true?
Thanks,
Reed

 

With 121K miles on the Corvette, it is likely to benefit greatly from a full re-bush of all the suspension. Both front and rear. It is a bit of a pain to do, a press really helps, and if your ball joints are the OE ones they could stand replacement "while you are in there". The newer bushing kits are not bad on noise, lube generously. When I did my '84 I bought extra lube along with the full kit and made sure that all the moving parts got covered. Minimal noise and a much more controlled ride. If yours is a Z51, you will feel every crack and sand grain in the road!

 

with 120K miles they most likely all need to be replaced. I've been slowly doing sections of mine. 4 years ago did did the dog bones in the rear as well as the sway-bar and end-link bushings.

I don't see how you would be able to "re-lube" pressed in bushings after assembly. All of the advice I received at the time said to just be use a lot of the special lube supplied at the time of initial assembly which I did and have not had any squeaking issues. This past fall when I had the rear end swapped out we did the bat wing bushings as well. To me that made a significant difference in the feel of the car.

 

Mine had 130,000 on it when I bought it. When I replaced all of the bushings I had a couple that had almost worn thru the rubber. Much longer it would have been metal to metal and could have been expensive. Make sure to use the recommended lube for the bushings, buy extra lube with the bushings and lube them well. Mine have been in for about 10,000 miles and I haven't had any problem with squeaks in the suspension. A press will make the job much easier. Make sure to use a spacer between the arms of the front upper A arms so that they don't bend or break. New bushings will make a huge difference in the ride and handling of the car. Have fun with it.

 

Thanks for the feedback guys, makes me feel a lot better about replacing them. I'm sure I'll get around to doing the bushings in the rear, but that's a little lower on the priority list.
Thanks,
Reed

 

When you do the rear, it makes a lot of sense to pick up a set of the dog bones and lower arms, change the bushings out and then exchange the 6 struts (dog bones and arms) in a single operation. You can do that in an afternoon. It makes a big difference in ride.

 

Take a look at the Global West control arm bushings. They are pricey, but I would never use poly again in any bushing front or rear.

 

Hi

Did my front and back to poly bushes at 170,000 miles.

The front control arms on my 85 the bushes had minimal wear, the rear however were pretty bad. The dog bones (trailing arms) were fine however the strut rods were shocking, the inner most bushes were down to the metal sleeve.

Now it is not an easy job, you will need a drill and large Vice and sockets for pressing old bushes out and new ones in.
Tip cut the outer rubber off the bush, then drill holes through the old rubber bushes with a small drill bit. Hammer a flat blade screw driver through and its easier to pry them out, or use a vice and socket to press them out.

Apply lots of the lube in and out the bushes, its been a few years since i did mine and no squeaks. They say after 10 years they may need to be greased again, i did think of fitting grease nipples for future use but never did it.

The rear is quite easy however pay attention to the inner strut rod, camber bolt end washers take a picture when removing them from the car so you know where they go.

Now the Front suspension, removing the upper control arm bushes was a real pain. Remember to drill lots of holes in the rubber bushes be careful not to damage the aluminum!!!!! even after drilling lots of holes at each end they are long bushes. Takes a lot of effort to remove them with a vice and sockets, Assembly needs a piece of metal to support the A arm when installing the new bushes. If you do not use a support on your A arms you will destroy your upper A arms.

Good luck, its a job that needs doing but will take a lot longer than you thought it would.

The prothane bush kit i got was for the entire car (see link below), it came with bushes for all years C4. Unlike some other kits you wont need to stop and buy bushes for your particular model C4.

https://www.ebay.com.au/itm/Prothane...EAAOSwEzxYekgL

 

Have you used these on your Vette? Anything special about the install process?

 

Does Global west make a solution for the rear? I can't find one....

 

Those Del-A-Lum bushing sets have essentially no compliance outside of their single axis of rotation. That's fine for every control arm front and rear except the rear trailing arms. They don't make them for the trailing arms because they would bind badly, and maybe eventually even wear or break the brackets. You could use them for the camber rods, however - I'm not sure whey they don't offer those. And I would really consider them for the front control arms.

I don't even recommend poly bushings for the rear trailing arms. The only really proper alternative to stock rubber bushings there is rod-ends. I've recently switched over from stock rubber to Banski rod ends, and they don't seem to hurt the ride quality or noise at all. They do seem to control rear steer under power and braking somewhat better, based on one day of autocrossing.

 

Exactly. That's what I was eventually going to get at; Chump poo-poo'ed urethane bushings and touted Del-A-Lum...but they won't work at all in the rear and although not ideal, urethane would work better in the rear. Even the camber rods move laterally, as the trailing arms go through their rather small radius arc. The best solution in the rear is heim or spherical bearings.

If only there were an affordable spherical bearing solution for the rear....


.

 

Now that you mention it, that's very true. Totally escaped me! Yeah, so that explains why Global West doesn't offer any rear bushings. FWIW, I helped a friend install a bunch of Delrin bushings in the rear control arms of his 2003 SVT Cobra (axial movement only in those arms), and they were great. I recommend them highly where the movement is truly only on a single axis.

One can dream, can't one?

 

I fitted Banski trailing arms and Banski strut rods with heim joints, i hated the offset camber bolt shifting after wheel alignments. I can now set my camber spot on and it does not change.

I found the poly bushings stiffened the rear suspension quite a bit, they resist movement especially at the dog bones.

Have no complaints about the poly bushes on the front suspension.

 

Are the heim joints sealed so they stay clean or are you track only?

 

That was the primary reason that the previous owner of my car installed the Banski camber rod. Especially with sticky autocross tires, the rear camber setting kept changing, and no amount of tightening the bolt could stop it.

Agreed, and I have lower poly offset bushings up front to help get more negative camber. They work well.

FWIW, I drive mine on the street and they hold up okay. Best bet is to use the rubber boots that Banski sells as an option. But also, the rod ends can be replaced for about $15 each, so no biggie if one wears out.

 

There even less cost effective when you take into account replacement when they load up with grit and wear out quickly.

I avoid spherical bearings on street driven cars because they don't really last at all.

To the OP's question, if you're in there, replace everything that moves, and do it all at once, or in quick succession. If you do that, you'll end up with essentially "new car handling." If you replace the most worn out part and drive it, the rest of the thing will still be loose and shakey, and that will stress and wear your new parts much quicker than if you replace everything at once.

If it's a daily driver and you're sensitive to down time, consider getting "spares" of the control arms and dog bones and other parts. Take your "spares" with new bushings and ball joints to the machine shop, get them refreshed with new parts. Then the "repair" is merely swapping parts. That's far easier than pulling the thing apart (dealing with 30 year old fasteners that might be seized or damaged), taking the parts to the machine shop, waiting on them to finish and putting it back together. You take the variable time that's out of your control out of the equation with a set of spares. I even keep spares for vehicles that are popular among my friends and family, to facilitate "suspension rebuild jobs" every 100K miles or so.

 

Ahem...see end of post just above yours.

 

Hi
The rubber boots supplied by Banski work well, sealing the heim joint from water and dust.

You can also cover the boot with wax or grease to protect them further,

Lee link below... look at the photos

https://www.banskimotorsports.com/c4-corvette-trailing-arms.html

 

I only recommend parts that I have first hand experience with.

The only difference really in installing these is drilling for the grease fittings and then pinning the upper control arm nuts.

Got them in two race cars and a street car.