boostwhipped24

So I just bought my 99 z28 a few weeks ago. The guy I bought it from had punknown lowering springs on it and horrible stagg shock. It set the car way to low on the front. And rode like **** and had a clucking noise in the front when I hit a bump. I just delt with it for a few weeks and mustered the parts together.So I got 2 questions.

I bought 2 upper and lower control arms, ball joints and the 2 isloators for the top of the shock mounts and 4 SLP Bilsteins with BMR springs for the car.


1) I was digging on rockauto an seen there is something called a (strut bearing plate insulator) and a (coil spring insulator) both of these parts look the almost identical, what's the difference.


2) my upper control arms didn't come with the metal bracket in the middle that mounts the shock assembly to the strut tower. Do I need these or will me old ones seperate from my old control arms and do me ok.

Thanks for the help the car has 150k and still has the factory ball joints rivited in and I want to get this thing back driving good again

BMR Tech2

iTrader: (5)

The isolator is just a rubber "washer" that keeps metal to metal contact from the spring and spring perch from happening, which can cause noise and vibrations. You can reuse your old one, or buy new if you prefer. Either name will be the same thing. You can even wrap the bottom coil in heater hose to achieve the same isolation effect.
The upper control arm mount is fine to re-use. You simply unbolt the upper arms from them where the bolts pass through the bushings and the new units will slide right back in their place. It may seem a little daunting now, but the front of these cars aren't terribly hard to do. Good luck, let us know if you need any more help!

boostwhipped24

Sorry for being and idiot, but what exactly is the spring perch. I know my new bilesteins didn't come with springs seats. So I'm not to sure about that yet either

BMR Tech2

iTrader: (5)

So I got a little confused after going over your post and went on rock auto and looked it up myself. The parts you are referring to are infact the same piece, but they go above the upper strut mount to distribute the load of the shock. Not quite sure why they are calling it a coil spring insulator. Those are normally the rubber liner piece on the bottom of the spring to isolate it from the spring perch. The pieces you are looking at I would recommend replacing while you are in there as well however. They clamp in with the stud on top of the shock along with the upper strut mounts you already have.
As for the actual spring perch, it is a round plate that sits on a snap ring on the body of the shock that holds the base of the spring. You should be able to transfer your factory ones over. Bilsteins do not come with these new, so most likely you will need to do this.

boostwhipped24

Ok thanks for the help so is the perch is the same as the spring seat is that right?

The piece I was talking about is the is the metal bracket the goes in the middle of the upper control arms. It's the one the shock mount sandwiches between the strut tower. My new control arms didn't come with them.

Corvett z07

iTrader: (2)

The metal piece that gets sandwiched between the shock mount and the frame of the car, I don't believe anyone sells aftermarket ones of those. You're kind of stuck reusing yours or buying used ones off eBay or getting some from a local junkyard. In all honesty though, 100% of the time you can reuse them unless they are bent which is very, very unlikely.

Check out my pic below. The assembly from bottom to top is shock, metal spring perch, coil spring seat, spring, bumpstops and shock boot, shock mount (which is right above my two fingers, it also is unbolted from the engine bay with 2 bolts and 2 nuts), the coil spring insulator (also called strut bearing plate insulator on RockAuto), and the one nut that holds everything together, which is rusted to bits in my picture.

My car has 160k+ miles on it, hence the horrible rust that creeps in there. Also a little heads up of what you might find under there. You can reuse your coil spring seat that sits below the spring if you take apart your old assembly, then you can salvage that part. Your shock mount could possibly be reused, depending on the condition. The coil spring insulator, IMO should be replaced as that's a very vital piece even though it doesn't look like it is.

My 2 cents

boostwhipped24

Wow your rust is way worse than mine lol I pulled it all apart already to try to diagnose the problem. Nothing had any rust so I guess I got lucky. Thanks for your help man very helpful I was ready to tackle it today outside in this 30° weather till I found my bilsteins did come with spring seats


What exactly are you referring to as the bump stops and boots not sure if I have either

Corvett z07

iTrader: (2)

I'm not familiar with SLP Bilstein shocks but the "boot" is just the blue plastic protective piece at the top of the shock. Not sure if Bilsteins come with new bumpstops or not, if not you can pull them from your old shocks. The bumpstops slide around the shock shaft underneath the boot. I believe they go in a metal cylinder looking thing that just sits on the yellow shock housing. They're there from keeping your shocks from bottoming out if you hit a severe bump or of the sort.

Don't quote me on any of this because I have different shocks that are a little different, but with the same formal design, get Sam in here and he'll tell you how it goes together perfectly.

boostwhipped24

Thanks again man, the rear shocks came with boots but not the front