The Fantastic C4 Corvette Aluminum Independent Rear Suspension

Today we're taking a looking at C4 Corvette independent rear suspension assembly. Made almost entirely of aluminum, this suspension was an engineering marvel of its day, and is still highly desirable now among hotrodders and custom builders for it look and functionality.
Watch as I go through a basic description and component Identification, and talk about how it's mounted in the C4 chassis.
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Thanks for watching👍

[@paulmoss7940]

Man ,that's a great explanation. I never fail to learn something from you ,as you obviously know your stuff. I'm Still enjoying a 96 LT4. Thanks for the content.

[@VetteSource]

Paul, always good to have your input👍. I was out enjoying my LT4 as well the other day. Now if I could just figure out how to get all the LT4s together one weekend for a cruise😁

[@cam3002]

A little bit of trivia to correct a statement made about the history of independent rear suspension. Not trying to take anything away from your fun video. In 1922 Lancia Lambda had the first independent rear suspension. Lancia did a great deal of innovation and had many firsts. A more mass produced car in 1951 was a the Mercedes Benz 300 Coup. It had independent rear suspension. The drive train was used on the more famous 300 SL that started in 1955 I'm sure there are other examples but that is what I can think of off the top of my head. Keep up the good work!

[@VetteSource]

Hey CAM, excellent information and something I definitely missed. Thanks for sharing the information. Appreciate the kind words, and glad to have you along for the ride👍.

[@dukeman7595]

No other manufacture can compare with corvette. I owned 1963 stingray which I had to have lined up, blew my mind; the car itself was nothing compared to the newer ones but was way ahead of it's time in 1963 in my opinion. Great info, Brian always look forwar4d to your videos.

[@VetteSource]

Yep, once a Corvette gets under your skin it's hard to get them out of your mind👍.

[@deanmarshall9751]

Thanks great description. I’m building a 59 Chevy Apache here in Australia and I’ve got the c4 front and rear going in with the Flat Out Engineering fitting kit with Aldan Coil overs

[@VetteSource]

Thanks, appreciate the feedback. Sounds like you have some good piece for your build. Should be a good handling ride👍.

[@forgotten320]

Flat Out Engineering are great guys, just was at there shop a week ago. Guy that helped design everything is a aerospace engineer

[@anthonyrichard8001]

GREAT FILM AND TALK!! I HAVE A 86.... THX!!!

[@VetteSource]

Thanks Anthony, glad you enjoyed it👍

[@CEOsario]

Nice job...Thanks for sharing...

[@VetteSource]

Glad you enjoyed it👍.

[@Mr.Vazquez]

Such a great vid thank you sir, and yes plz make a brake down.

[@VetteSource]

Hey Joshua, glad you enjoyed. Will have the next one out soon👍.

[@bansheemopar]

That is a later C4 rear suspension. The earlier ones has the e-brake as a little drum inside the disc.

[@VetteSource]

Yep, that's correct

[@goldie_box2904]

I’m hoping a C5 pops up in my area soon so i can get front & rear brake calipers. Not sure how much of a difference is from C4 to C5

[@VetteSource]

The rear calipers, not so much since they're not taking on a large portion of the braking demand. I have some customers that have performed the C5 brake caliper conversion on their earlier C4's. For 95-96 C4's it's kind of a wasted upgrade in my opinion since they already come with the 13" rotors and larger calipers.

[@ktm450smr2]

how does this suspension behave in corners compared to other suspension systems?

[@VetteSource]

Hey KTM, the C4 Corvette IRS is quite a capable and nimble unit on the open road and twistys of a road course or mountain road. However, they can be a bit "glitchy" when you make aggressive low speed maneuvers, resulting in you facing 180 degrees from where you intended or even worse in a ditch.

[@MichaelIng123]

Great to see people still interested in the C4. Is it correct that the half shafts are a functional part of the suspension to locate the wheel and a bad u joint will let the wheel wonder slightly? They are similar to the jag in that way? I know the 70s had the same issue.

[@VetteSource]

Hey Michael, it is good to see people enjoy the C4's, they are well built and designed Corvettes. The half shafts on the C4 rear suspensions are a bit more isolated due to having several additional hub attachment points. Even though you will hear the clicking of a bad u joint, it's not enough to usually cause any wheel deflection unless you have an additional worn component, such as the camber rod or dogleg bushings. Thanks for the comments👍.

[@MichaelIng123]

@@VetteSource it seems if you took the half shaft out the wheel would lean in due to lack of upper control arm. I'll check mine out when I replace my u joints. Seeing your video makes me wonder why I have put it off. I'm a slacker and the car hasn't been driven in a while. Thanks for the response!!

[@VetteSource]

Under normal conditions it could do that, but with the C4 IRS, there are 6 separate points of contact between the unibody/differential/shock and the rear spindle that hold it securely in place. The first two are the doglegs, then the lower camber rod, spring mount, tie rod, and the shock mount. You can almost pull the half shaft out of suspension assembly without disconnecting any of the other components, but it can be tricky. I usually recommend disconnecting the lower camber rod from the spindle(located at the 6 o'clock position) along with the tie rod end and spring bolt. This will allow you to pull the spindle outwards freeing up the halfshaft. When you have some free time, check out the playlist I created for my 92 convertible that had rear suspension damage. kzbin.info/aero/PLAM-V1w3acpig5KsFXSKCa98sgjBNpBxo In the video I remove the bent dogleg and tie rod so I can get it back into a normal orientation. You can pretty much see everything that's involved in that area and how to get it loose. Let me know if you need anything else👍

[@frankpavan7865]

Great video ! I imagine my 1996 coupe with LT1 motor and Z51 handling package has a Dana 36 differential ? Thanks

[@VetteSource]

Hey Frank, yes that's correct. Dana 36 is installed in automatic equipped cars, while the Dana 44 was used exclusively for manual transmission equipped cars.

[@frankpavan7865]

@@VetteSource okay. Thank you .

[@youtubesucksdonkeyd6906]

I have a feeling with a low gear rear and all that torque I should be able to spin wheels on command

[@VetteSource]

This suspension design is definitely suited for transferring the power to the wheels. However, the weak link is the side yolks and half shafts. They tend to twist and rip apart under too much load. That's why the Dana 44 unit with the larger 8.5 inch ring gear is highly sought after.

[@tomb5396]

Hi, possible to install C4 suspension into C3 vette? Thanks

[@VetteSource]

It is possible, bit will require quite a bit of modification and fab work to the frame get it mounted.

[@ImmortanDan]

Hey, C4 owner (and car diy greenhorn) here. I might have to get parts of that assembly out since I need to change out my driveshaft u-joints. Is there a hazard associated with getting that leaf spring out that I should watch out for?

[@VetteSource]

Hey Dan, the leaf spring is pretty straightforward. As long as you support the outer ends at the spindle with a jack when removing the through bolt, you'll be in good shape. Once you take the tension off the spring and then remove the bolt you can lower the jack down. Once you have that done, you can remove the center mount bolts/brackets at the bottom of the third member.

[@CaseTheCorvetteMan]

There is some minor wrong info here, the DANA 36 had a 3.31:1 ratio, and it was an option in 1984. You can get a 2 series gear set in 3.54 and 3.73 for the 36, they're after market sets. The 1984 cars also had DANA 36 regardless of transmission. DANA 44 never came til 1985, i have only seen 1 car with a factory 3.54:1 DANA 44, was a 92 6 speed ZO7 car. The engine in that car was stock, and to be honest you could hardly tell the difference between the 3.54:1 and the standard 3.45:1 that almost all of them had. The 3.33:1 was an option in DANA 44 as well, and i have had a few of those through over the years. 3.33 was a great ratio to use for an auto car 36-44 swap. 84 to 87 were the same as each other, 88-95 were the same as each other, and 1996 had a few slight differences. This one is from 88-95, i'd have to guess probably 88 or 89.

[@VetteSource]

Cool, thanks for the comments.

[@kennygibbs9627]

Does, my 89 have the same.

[@VetteSource]

Yep, exact same setup👍

[@willefixit]

got danna in my plymouth and dodge/ and jeep

[@VetteSource]

That's correct, thanks for pointing that out👍. I forgot to mention it in the video.

[@makosharkcnc7730]

1993 is the year i have is it different? if so what

[@VetteSource]

Nope, 88 and 93 are pretty much the same with the exception of a few small things like the tie rod, camber bushing, and ABS sensor design.

[@willefixit]

84 vette was avertised as firsh car to hold i g on skid pad /z51 suspension

[@VetteSource]

Yep, another good point that I forgot to mention. Plus the spring rate on the 84 Corvette was super high compared to the later years.

[@willefixit]

@@VetteSource i love and hate vetes lol . you have helped me more than once /dealling with 93 now arsr intermentint code . got old brick said speed sencor once . been servicing thihs one for a few years . 75k on it been hit saw qutartr repaif will see . did fueltank breakes injectors opti 134a conversion .powerwindow repair etc i for got . late rambling but yea been folllowing u 4 a few years thankz 4 sharing

[@MARYLANDMENACEracingrivals]

I just bought a c4 1985 today. First time vette owner. On acceleration and deceleration the car sways. If you could help lead me to the right direction to fix the problem I’d greatly appreciate it

[@VetteSource]

Hey D&D congrats on the purchase. First thing I would check is the lower camber rods that run from the differential to the spindle. You most likely have some bad bushings there. While you're at it, check the trailing arm bushings. Odds are those are worn out as well. Let me know how it goes👍.

[@MARYLANDMENACEracingrivals]

@@VetteSource will do. For some reason I couldn’t find your video that you mentioned where you worked on your rear suspension. Any way you could link it if it would help me understand what to look for visually.

[@VetteSource]

I haven't done a teardown video yet, but I do have this complete removal video that shows the components I'm referencing- kzbin.info/www/bejne/qabFp6V8nNBpoaM

[@Clarity5970]

Is there any difference on C4 ZR1 rear suspension?

[@VetteSource]

Nope, they're all the same.

[@willefixit]

modle t had transvers spring

[@VetteSource]

Hmm, didn't know that. I like the early 20 century cars, just never had a chance to get my hands on one.

[@marzsit9833]

so did many ferrari cars that are worth millions of dollars today.

[@Clarity5970]

Why is there no drain plug on C4 rear end?

[@VetteSource]

Good question I always wondered about myself. If I had to guess GM probably didn't want to create a potential failure point in the aluminum housing under extreme loads.

[@ulyssesvazquez387]

Is it possible to install a c4 suspension on a c2 frame?

[@VetteSource]

Hi Ulysses, while it may be possible to execute all the cutting and modification to a C2 frame to adapt the C4 suspension, most of the time it's easier to buy one of the aftermarket frames that are built up to install the C4 suspension directly.

[@juliodiaz8280]

What Trans came in the 87 c4 automatic?

[@VetteSource]

That's a 700R4.

[@lindyp38]

Can u do one for a 93 ?

[@VetteSource]

Hey Mario, sure can. I have this one and two other complete assemblies from an 1986 and 1991. I forgot, are you here in the states?

[@lindyp38]

Yes. NY

[@VetteSource]

Great, you can reach me by phone @8326547367, or email [e-mail].

[@45auto82]

Never knew any rear diff assy had tie rods. Why? Is it just only for adjusting camber? Great description and details Bud. I Watch every thing you shoot!

[@VetteSource]

Yep, having the tie rods like you would see on the front suspension looks a bit odd, but it's used to adjust camber like you were thinking. Thanks for watching the videos, my friend. I've been enjoying sharing the information👍

[@PeterHatch-mx7zc]

Thks for the video have three full sets going to norrow one set that has the Dana go the idear from utube build the guy put it in to a Triumph G.T. and way my build is alot dont like

[@VetteSource]

Hey buddy, I'm glad you enjoyed it👍. Sounds like you have your hands full with three of them to retrofit into those other cars. It should be a fun project👍.

[@willefixit]

preety stout / my budy put ford 9inc in his back in the day

[@VetteSource]

Oh yea, like those Ford 9 inches. Awesome differential👍

[@datboired832]

Im in Pearland omg ide love to pick ur brain man. I have an 86 iroc no its not a vette but has the 305 tbi.

[@VetteSource]

Sure, just look up my contact information on my social media accounts. I am close by👍.

[@willefixit]

lot like a jag

[@VetteSource]

Yep, it does seem to have quite a few of the same properties with the exception of the steel mounting structure surrounding the Jaguar IRS.

[@willefixit]

@@VetteSource jag rears in lots hot rods in board disc was pain in the ass in regular jags

[@marzsit9833]

@@willefixit inboard rotors were only a pain if you needed to replace or resurface them. that's why regular brake pad inspections are very important on a jag so you don't trash the rotors.

[@willefixit]

jajs hard to work on under state ment

[@willefixit]

jags restored a xljshe t back in the day 12 cylinder turmo 375 gm trans chrsler rear three day to get drive train out

[@VetteSource]

I'll bet that was no fun.

[@stevemayo1175]

DOG BONES Not LEG's

[@VetteSource]

Ok, potatoe or potato. I get it.

[@stevemayo1175]

@@VetteSource I am Not Hating on ya young man but Dammit Boy Ya cant even get TATER Right Either ROTFL

[@darrinwatts9229]

Alot of bs talk and no substance

[@VetteSource]

So tell me what should I have talked about?

[@20alphabet]

Lol, nothing "fantastic" about dangling rotors and calipers at the outside end of the axles.

[@VetteSource]

oh well, that's why Corvettes aren't for everyone. Thanks for watching

[@20alphabet]

@@VetteSource Because the rear suspension isn't "fantastic"? I think that with a Jaguar rear replacement it's fine. But no, the rear suspension as is just ain't sufficient.

[@VetteSource]

Now how did I know you would be a Jaguar guy?😁 I think the Jaguar IRS is an cool setup, but maintenance wise a C4 Corvette IRS is much easier to work on and repair. Remember also that just about every restomod in the world is running a C4 Corvette IRS, so they must be popular for a reason.

[@20alphabet]

@@VetteSource Lol, not a "Jaguar guy", but a performance guy. And the reason for the Corvette rear's frequent use is they're cheap and plentiful by comparison.

[@VetteSource]

That's the truth, and much easier to polish that aluminum that chrome the Jag parts👍