Colombo

iTrader: (5)

yesterday i changed out the rear springs on my BC coilovers from 8k to 10k now the car sits alot higher then it did with the 8k. due to the change in stiffness? anyways. if i drop the coilovers down to where it sat with the 8k spring will it throw off my alignment? or is my alignment thrown off already due to this spring sitting the car higher?. firestone told me they could not sell me the lifetime alignment thing due to the fact my car was modified or i would just bring it in and have it readjusted.

GeauxLadyZ

iTrader: (9)

Any change in height will = thrown off alignment.

Colombo

iTrader: (5)

thought so...thanks! hope firestone honors there alignments for atleast a couple of days

T_K

iTrader: (5)

Assuming nothing else was changed, and you could bring the height back down to "exactly" where it was prior, then in theory it shouldn't alter your alignment. If not going for an alignment, just dropping the car as close to the previous height as possible, should be a good ball park until you can get an actual alignment.

EDIT: The change in height throws off alignment, but if that was the only change, and it's returned to its original position through the same mechanism in the suspension, there should be no change in alignment. The resting position of the 10k spring extends a bit more than the 8k spring, it's rest length with vehicle weight is just taller than that of the 8k. Simply adjusting the spring perch to bring the resting height identical to the 8k, wouldn't alter anything.

Colombo

iTrader: (5)

ill try that thanks!!

GeauxLadyZ

iTrader: (9)

Agreed.

Eyeballing it to same original height should bring you back into spec or at least very close to it.

The actual process of changing the height will not throw alignment off, as the orginal set angles are locked in via toe bolts/camber arms. It is if you leave the car at a different height that will result in out of spec.

The sooner you move it back to original height, the better, though. Once you get the spring preload nut back to its original position, you should take JasonZya's advice and make a mark in the threads on your coils where everything is set. That way, if you ever have to adjust height without getting it realigned, you always know where to set everything back to via the marks on the threads and you'll know that once everything matches the marks, your car will be back to its original height and therby in proper alignment as well.

Colombo

iTrader: (5)

i wish i would have measured how low the rear war from the fender that way i could drop it down to almost exactly the same height. now im just going to have to guess and who knows if it will be correct. i guess i will have to drop it then go get an alignment check and hope firestone fixes it for the free if its off thinking it came out of spec but asfar as future adjustments im deff going to make a mark on the perch. thanks for the info!

T_K

iTrader: (5)

Assuming theres approximately 700lbs resting on each spring. 8kg/mm spring converts to 450lb/in. Theoretically should compress the spring about ~1.5in. 10kg/mm converts to 564lb/in, theoretical compression is ~1.24in. So in theory, lower the perch height about a quarter of an inch and then try to eyeball the fender gap from there.

JasonZ-YA

iTrader: (60)

All the answers here have been spot on.....

but in the end, your gonna have to go get an alignment again........there is no way for you to eyeball it back to the right position since you didnt measure at the fenders to begin with......to guess at the height, odds are your gonna be out of spec, by how much, depends on how good your "guess" is.....

Prior to making any changes:
1. I note down where exactly I park in my garage - which is relatively flat. (use chalk on the ground, blue tape, etc)
2. I then push down on the hood, hatch area and ensure the suspension is settled.
3. I measure the fenders, like shown in the fsm picture below.
4. I check to ensure the car is level and remember where the bubble level is sitting.


I mount a RV temporary bubble level on my car and ensure I have it all covered!


-J