When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi, first time poster on this forum, so be gentle if I'm in the wrong area. I purchased this suspension for use on an aftermarket frame going under a tri-five chevy. I know the rear end is a Dana 44. I have no idea what I have for front suspension. Was told it came off of a 1990 Vette, I do not have the VIN number. Is there any way of identifying what I have for the purposes of rebuilding? Option codes cast or stamped into parts that will help with identification? Front needs ball joints and A-arm bushings, but I don't know if it's the base or HD suspension. I am not sure what the rear needs at this point (probably everything). Also, is there any resale value on the leaf springs, front or rear?
Visually it's likely what you bought it as but for sure '88+. You could measure rotor diameter on the fronts to determine if base or HD brakes. 12" rotor would be base 13" rotor HD, shopping for brake items 12" = JL9, 13" = J55. The springs will have a code on them that's very visible and dependent upon the code and visual condition could vary widely in value. Sway bar diameters and whether solid or tubular would determine value. The rear on the bottom of the differential should have information to determine ratio etc. If a '90 it would be most likely a 3.33 but maybe 3.45. A wheel rotation and pinion rotation count to verify. Who knows maybe changed? It wouldn't be unusual to find a ratio other than stock. The loose piece in your snapshots hints '90 also, prior to '90 I don't believe that was used.
*** You could clean the shocks and if they're non-leaking they might have some value also.
*** The front crossmember should have a part # and also a date code that could be used to further ID it's origin. I would assume if a '90 you'd find 10080751 on the crossmember.
Thanks for the info. I have not checked the rear end ratio, but I see red RTV between the pumpkin and the batwing, so I'm pretty sure it's been apart.
As far as replacing the A-arm bushings (or batwing bushings), is there a difference in them between base and HD suspension? Also, what are the good brands you guys use for either poly or rubber replacements?
If by some chance this is a Z51 suspension from 1990, then those springs are desirable and you could sell them to someone. Check each spring for a three-letter code. In front you'd want to see FHB and for the rear you're looking for NYU. Any others are worth something, but won't be a sought-after. Either way, if you're planning to use coilovers instead of the monoleaf springs, you can certainly sell the monoleafs for something.
For bushings, you can't get new OEM rubber ones anymore. The hard red or black poly bushings are ubiquitous, and they are fine for the front control arms and both sway bars. They are not fine for the rear trailing arms and lower lateral camber arm. You really want either more flexibility in those or else ditch the axial bushings altogether and go with rod-end links from some place like After Dark Speed. The only axial bushings I'd recommend in those spots are the more flexible urethane ones from SuperPro. You can of course use their entire kit for both ends of the suspension, too.
The rear end might have the Gear Ratio and Date Code etched in to the housing. If you post the Codes that may or may not be on the springs you will quickly figure out what era and spring rates they are. As far as suspension bushings and ball joints go they are pretty much the same for C4s. Spring rates, Shocks and Sway Bars changed, but not much else. You will need to know the Diameter of your Sway Bars just like any other car to get the right bushings but that's it.
Yesterday I started teardown of the Rear and found the spring stamped:
_NYR_
__5__
So from another thread on here, that decodes to: "NYR 85 base(?) 86-93 base, 89-90 w. FX3&Z51, 90-91 w. ZR1" I read this as "it could be anything but a Z51 suspension only car....if it's a 1990 model yr.
Haven't gotten the front spring out yet. I will measure diameter of the sway bars, good tip. I didn't see any etchings on the rear housing, but spinning the axles it's 3.XX : 1 LOL. I'm assuming it's a stock 3.31 or 3.45.
Thanks for the info so far guys, this has really been a big help.
Yesterday I started teardown of the Rear and found the spring stamped:
_NYR_
__5__
So from another thread on here, that decodes to: "NYR 85 base(?) 86-93 base, 89-90 w. FX3&Z51, 90-91 w. ZR1" I read this as "it could be anything but a Z51 suspension only car....if it's a 1990 model yr.
Pretty much. There was another RPO code of "R9G" that also used the NYU rear spring. I don't know what cars that came on, but those are the only two C4s in 1990 that used this more desirably spring. The FE1 and FX3 (coupe and convertible) and even the ZR1 use the softer NYR spring you have. It's worth more than nothing if it's in good condition, but the NYU would be desirable as an upgrade when paired with the FHB front spring.
Pretty much. There was another RPO code of "R9G" that also used the NYU rear spring. I don't know what cars that came on, but those are the only two C4s in 1990 that used this more desirably spring. The FE1 and FX3 (coupe and convertible) and even the ZR1 use the softer NYR spring you have. It's worth more than nothing if it's in good condition, but the NYU would be desirable as an upgrade when paired with the FHB front spring.
Code on the front springs and wash the shocks(front and rear) off and post the information on the shocks. There should be legible information on the shocks. You shouldn't need to actually remove the front spring to get the code.
Well, mystery solved. I did get the front K-member torn down last night, the front spring is FHA. I also found the "other" build sheet in the K-member! I didn't even think to look in both sides. So now we now it was an FE1/FX3 car, GT7 (3.33) rear end, 12" rotors front and rear. I do have the Bilstein shocks, but the little adjustment motors on top of the shocks are gone.
Thanks to all for the help. I'll be lurking still to see what upgrades on this suspension are popular on the site.
You might check with the people who built the Frame to see what Springs they recommend. I'd be willing to bet they don't have an answer. The Tri 5 may weigh more that a C4 so I'm thinking stiffer Springs might be a plus. Van Steel would be one Vendor to start looking. I'm sure what you have will get you started and when the time comes to drive it you will know more. The FX3 Shocks are not going to do you any good you don't have the electronics to run them anyway. Getting them rebuilt is or is not an option depending on what Bilstein feels like doing this decade and most FX3 cars no longer have them because of this. If they are complete they might be worth something in the parts for sale on this site.
The FX3 Shocks are not going to do you any good you don't have the electronics to run them anyway. Getting them rebuilt is or is not an option depending on what Bilstein feels like doing this decade and most FX3 cars no longer have them because of this. If they are complete they might be worth something in the parts for sale on this site.
Don’t think he has to worry about completing the FX3 setup as the shocks are not FX3.
Identifying suspension for rebuild
