Question on adjusting BC coils

MattP725

So I am finishing up my install of my BCs and SPC arms... my question is, I know people adjust the front height by rotating the housing after removing the brake line and speed sensor. Can I adjust the rear shock in the same manner? Will the housing rotate while it is still bolted in if I just remove the locking collar? I would probably need a strap wrench to turn it I assume.

Also can rotating the shock damage the internals? Someone on the board said they blew a shock by doing this.

Last question... can I put the wheel on and lower the car without the strut bolted (just the spring) to gauge the height before bolting everything in? or will lowering without the rear strut fastened alter the height of the vehicle?

Just trying to make this as easy as possible since I generally only get an hour or so of daylight after work... I've been adjusting these for a few days now until I run out of light.

Deadman

To adjust I believe you will have to have another Jack under there to compress the spring and adjust accordingly . Someone else chime in but I think that's how you do it . Been a while since I've mess with CO's

Edit: Nvm I think after reading your question again its a bit different than what I thought you were asking sorry ! :0

sixpax

...loosen the bottom collar of the two that are up top...loosen the only one at the bottom. Use a strap wrench and turn it the appropriate direction. Can do by hand but is fairly hard to turn. If you do it correctly, the strut is not rotating at all, just the fine threaded internal piece is moving up or down inside the strut.

Can do it easily by hand without a strap wrench if you take the load off ... so another jack to compress the spring perch.

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MattP725

Rear, not the front.

sixpax

Sorry my bad. Same logic on the front. Not sure why you are unbolting anything, no need to ... at least with the ARK's which I assumed by looking at pictures are pretty much adjusted the same as all of them.

With most of the load off, and both the top and bottom collar loosened, you can easily turn the fine threaded piece either direction by hand.

Maybe ARK is different.

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MattP725

On the fronts (at least with the BC) you need to unbolt the brake line because the fitting mount is on the threaded insert (it turns with the coilover). If you don't the line would wrap around the strut assuming it was long enough.

The rears, assuming you are correct, wouldn't require anything to be unbolted from the housing.

Thanks for the info!

MattP725

Anyone able to answer my other questions?

"Also can rotating the shock damage the internals? Someone on the board said they blew a shock by doing this.

Last question... can I put the wheel on and lower the car without the strut bolted (just the spring) to gauge the height before bolting everything in? or will lowering without the rear strut fastened alter the height of the vehicle?"

corbin09

Am I missing something? You can adjust the height of the front coilover and the rear with a spanner wrench? You shouldnt be unbolting or turning anything to raise or lower it. Also dont spin the coil with the tophat attached to the car. I dont know if it would cause it to "blow" but it cant be good for it.

MattP725

Yeah you are not supposed to adjust the height with the spring... that changes the preload and throws off the ride... you are supposed to adjust the height by spinning the lower perch (or spinning the entire strut with the perch still bolted in). You have to unbolt those lines in order to spin the assembly... if you are just compressing the spring to lower it, you are doing it wrong.

Volk Z

Yes you can put the wheel back on with only the spring to check the height keep in mind that it will adjust slightly when the strut and pre-load are set but it will be within a half inch or so of that height with just the spring.

As for adjusting, i have installed BC coils on Z's over 7 times... Heres the scoop for adjusting.

Fronts- You only adjust by the single gold collar that locks the strut "fork" DO NOT adjust the upper 2 gold collars on the front as those have the stock preload set and you will have to reset preload on the front if you move these.
I believe counter clockwise lowers/ clockwise raises

Rears- For the rears once you get the desired height you will lock the 2 gold rings (seems to be usually a half inch to a quarter inch of threads that hang out from the bottom portion for a 1.5 inch drop- depends on your weight of course)
Then lower the perch and put the spring and top portion in that has the threads and gold rings and close the perch that holds them up by bolting the one large bolt that holds the spring in the perch.
Then you should have the strut installed but NOT the bottom portion. This is left off to set the preload.
** to set the preload in the rear you will get a jack underneath the perch that holds the rear spring be sure to have someone keeping a measuring tape on this while it slowly gets jacked up...You should set 1/4 to 3/8 of an inch of pre-load on the spring once you do that lock the jack in so it holds the spring in place. Now to lock in permanently you will spin the bottom fork of the rear strut until it lines up with its hole where the bolt slides through. Slide the bolt through and use the BC provided NUT they provided.

Tighten all bolts and set down... And your done.

-Chad

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MattP725

Chad so that is what I was getting at... if I want to readjust the rear, I need to basically remove the lower bolt on the strut since that determines preload. It seemed like you wouldn't be able to accurately judge the tension on the strut/shock in the rear since it doesn't control the height without removing the lower bolt.

I think I am the only one that feels like the front is easier to install/adjust than the rears.

ATL_Red_G35

Chad is correct with the preload of the rear. Though it takes a lil more work, it's to ensure that you have the best setting since the OEM rears make it slightly more difficult to adjust than the True Coilovers in the front.

What we usually do is:

1. Adjust the rear springs to the desired height
2. Install the rear shocks onto the bottom mount with the shock body lowered all the way, leaving the top mount free
3. Jack the bottom spring bucket up so that the springs are just about LOADED correctly (still able to turn by bare hand with the top of the springs flat against the top Gold perch/collar)
4. Starting to adjust the shock body and slowly raise it up so that the top mount will align and bolt up correctly with the 2 top bolt.
5. Bolt down everything and lock all the perches/collars.
6. Drop the jack and the springs should sit snug still

That should be the "base" preloading. Test drive, then readjusting the setting accordingly to how the car response

MattP725

That makes it much eaiser when you guys put it that way... hopefully the weather holds and I can get it all done this weekend. Thanks for the help.

Volk Z

Sorry guys i just noticed there were some new posts on this thread!

If you have any questions just PM me and i can call you if needed. I walked a fellow Z member on my350z.com through an entire installation.... The wife wasnt too happy as it was when we were out having dinner but i gotta help my Z guys/gals! haha

-Chad

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MattP725

No problem... install was smooth... no bumps, creaks, etc. Ride is surprisingly descent. Not much harsher than stock. Front is set really firm and back is really soft. It balances.