What I thought was a chattering diff is, surprise surprise, the entire car's worth of control arm bushings having gone kaput! The good news is that while the symptoms are now obviously related to them, the problems really don't extend any further than a lot of road noise/a bumpy ride, and that rare chattering noise that I've still yet to hear again since I last made a post about it a few weeks ago.

My question for those who have dealt with a full suite of these is - how much can I expect to pay? My looking online is yielding mixed results about the cost of one tire's worth, vs an axel's worth, etc and the numbers aren't really making sense. I've seen that prothane is a good option for the parts themselves (linked below) but my concern is the labor involved. I don't have a hydraulic press so I can't do them myself, but if I could find one, what's the consensus on the time commitment for the job? The rear ones are by far the worst offenders, so I may do those first anyways, but I'd like to know what my wallet is in for before I call and schedule her in or even ask for one of the shop's quotes in case they're way off. I'd like to order the parts myself and hand them off to the shop, so if anyone has better options than the ones I've found I'd love to hear it!

As always any thoughts are appreciated. Thanks!

Rear Bushings Front Bushings

Edit: I'll also do the ball joints while I'm at it even those are somehow in much better shape than the bushings.

 

You dont need a hydraulic press to do this job. I did mine using some large sockets, some steal plate and a large C clamp. I drilled holes into the old bushings to make it easier to get them out. I did the 4 dog bones as well as the upper and lower fronts all the same way. made a huge difference in ride quality

 

If you are doing poly bushes - like Prothane or ES No press needed to install, they go in pretty easy. I did all the bushes years back, recommend buying extra of their grease. No squeaks to date. I did use a 20t hydraulic press to aid in removal and it was a big help to speed things along, especially getting the “dog. bones” out of the upper arms - which did also require building bracing support structure so as to not bend the control arm. You can get a really cheap 6t or so press at Harbor Freight and it’s prob be overkill for the job, but worth it to have to make easier. I’ve used my press for lots of things. The poly bushes themselves don’t cost too much. Labor no clue, I was the labor. Getting the bolts out of the lower arms might be the longest part of the job.

I’m sure any second now the SuperPro rubber bush guys will jump in and say how awful the poly are. To each his own. I’m sure SuperPro rubber bushes are great. I’ve had no regrets in a fully poly bushed car for 5+ years. And no squeaks, thunks, clunks.

 

Interesting you caught me taking a break from doing this very job myself. Super Pro in the Dogbones and Polyurethane everywhere else. However, it sounds like You are more interested in having somebody else do the work I would recommend finding a Corvette shop in your area that has done it before to get a better estimate. This job is not any harder than a muscle car and with the C4 there is no need to compress any Springs so in some ways it is easier. I'm going to say that I will end up with about 12 hours labor to do it myself. However I'm putting early upper A Arms in a late C4 so I had to disassemble 4 of them. Your probably going to want to replace the Ball Joints and I found that Rock Auto really has a huge discount on them over my local auto parts stores. If you have any thoughts of doing it yourself there are a number of video's out there to watch.

 

One thing to note - you will need an alignment when this work is done. Find a shop that can have an intelligent convo about it. The C4 is not a modern car and uses shims in the front end. A place like TownFair is going to set the tow and charge you. They won’t touch the shims and likely won’t even know how. Those places had no clue when I would talk with their techs. Not saying it’s every one of those places everywhere but at least the ones I spoke to.

I called a local Corvette shop, and while they outsourced alignments they did point me to the shop they use and those guys knew exactly what I was talking about. With a refreshed suspension and a proper alignment you’ll be really amazed at what the car feels like compared to how it drives with it’s currently worn out components.

For this reason - I agree on replacing it all, ball joints, tie rod ends, end links, sway bar bushes, shocks, etc, everything that can wear is worn, these are old cars, now is the time! You will run the bill up a little more but it’s worth it.

this is the thread from when I did the front end of my 94 6 years ago. I had done the rear a few years prior to that. You may find it useful as lots of pics, challenges that the forum helped solve. 6 years later suspension is still great. you’ll start to see in the pics why I did more and more, you find thing when you pull it apart that are at end of life and why bother at all if you’re not going to correct it.

thread…
https://www.corvetteforum.com/forums...-overhaul.html

 

Thanks all, I appreciate the thoughts; threads have been bookmarked - jmgtp, the pictures are wonderful, thanks! Luckily the shop that I decided to switch to recently mentioned offhandedly that they have one guy who's allowed to work on Corvettes, so that's what I've got for specialists in the Tucson area and since he was able to get my front alignment damn near perfect even with the worn parts, I'd say he's worth repeat visits should the need arise.

I've been thinking about it over the day - I think the best option will be to fully do the rear stuff, then do the front when I've got the means. I'll get my head in there, poke around, and give it all a shot myself, just to say that I gave it a go with what little time I have to put towards this (she's a daily for the time being so I can't have her down more than a weekend). If I've got to put it all back together quickly and limp the half block to the shop, oh well, live and learn.

So, in that vein, what else is back there? Right now on my shopping list I've got the control arm bushings, sway bar bushings - 24mm for a '94?, tie rod ends, the ball joints and shocks were inspected and are fine (for now, lol), gonna do the brake pads while I'm at it and scope out stainless lines... Any other rubbery/plastic-y bits that could use changing? This is what qualifies as my introduction to the world of old/aging car ownership and maintenance, so forgive my ignorance on the minutiae. And at the end of the day, if I can get out of doing just the rear end in the neighborhood of a grand or 1200, I'm happy. The front can wait a (1) season.

Many thanks

 

Take a look at the upper shock mounts and the upper A-Arm rubber bushings. The condition of these will give you an idea of what the rest of them will look like. Air Polution is what destroys them some cars will be pretty good and some will be complete junk depending on where its spent its life. You could buy an extra set of Dogbones and rebuild them ahead of time if its a daily driver.

 

Sway bar end links, check wheel bearings for play, universal joints, batwing bushings, spring bolt bushes, rear tie rod ends and hope the inners are tight. Teflon washers which I’ve read are hard to find now, and re-torque the axle nuts, I went to ~180 lb ft. Check C beam bolts holes are not wallowed out and torqued properly. Consider beam plates. Good time to bring out the FSM and do the park brake cable adjust procedure at the rear calipers. Replace the soft brake lines. May as well do the diff oil too while you’re back there. No drain, but easy to siphon out with a stiff tube and applying a vacuum (a pneumatic bleeder makes it a quick job and your shop prob has one)

 

I strongly recommend against regular hard poly bushings in the rear trailing arms (dog bones) or camber/strut rod. These links have to move in more than one plane, but the hard poly bushings create a lot of bind when the link tries to move in any plane other than around the axis defined by the bolt. The SuperPro bushings are your best bet here.

 

As somebody who is replacing these today, I can say besides the high price Super Pro USA is a difficult vendor to deal with. The Web site is confusing, they don't return e-mails and they don't answer the phone during business hours. They ship partial orders with no invoice or note letting you know why. When you go back to the e-mail letting You know your order shipped it will say partial order shipped with no part numbers or explanation why. Currently the Dog Bone Bushings are 4-6 weeks on back order according to the web site. Thats about how long it took me to get mine, shipped in two different shipments. To get the correct number to do both sides you will need 4 orders. If you use the search box and type in 1990 Corvette and go down to "Trailing Arm Bushings " You will get bushings marked Toyoda. If I was to place another order, I would attempt to order them directly from Australia, thinking cutting out the middleman might make things go smoother.
Another note, else ware on Corvette Forum I have read that the 1996 Composite Dogbones use a different Bushing than the Aluminum ones. This does not seem to be the case with mine, the Super Pro Bushings fit nice and snug in mine.