Coilover ride height changed after new rear subframe??
 

Hello all, I just recently had some warranty work done to my Z lowered on BC BR coilovers at the dealership to replace the problematic rear subframe mounted differential bushing which has been broken and leaking after only 19000 miles. In order to replace this bushing the entire rear sbframe it is mounted in needs to be replaced. I recieved my car back from the dealer yesterday and noticed the rear ride height is now at least an inch higher than before?? I have no idea why this has occurred as the coilover settings were not changed, and the new rear subframe is a direct replacement. I have jacked the car up and verified that everything looks to be installed correctly. Any ideas?

Just a stab but maybe the bushings are stiff and haven't settled so the car isn't as low as before... maybe they redesigned the subframe? Hard to say because I doubt a lot of people on the forum have installed new subframes in their Zs.

That's really strange. Are you sure they didn't change the coilovers? If you're 100% sure that the coilover settings aren't changed, then I'd agree with MattP that it must be because of the bushings. A whole inch is an awful lot of discrepancy, though.

I haven't looked at the 370Z rear subframe, but on most cars there's 4 studs that are part of the body of the car that the subframe slides onto. Large nuts hold the subframe to the car. I've had a few instances where the subframe isn't lined up completely correct and ends up not being seated totally flush, which means you have to pull the subframe back out and try again. The subframe seems tight because it's kinda wedged in there. Happened to me twice on my own 240SX. Double check that you're not having that issue. If all else fails, take it back to the shop and ask them why it's not right.

Maybe they had to raise the front to get the car onto a 4 point lift not sure how low you were...

Chances are they replaced the subframe and tightened the bolts for all of the control ams with the car sitting up on the lift, leaving the suspension at full hang. So now that the car is down with weight on it the bushings are bound up and holding the car higher than it should be.

Try loosening all of the arms on the subframe side with the weight of the car on the wheels and than tighten, I bet it solves your issue.

They would have just jacked the car up or driven onto ramps or boards. Besides, his ride height is raised in the rear not the front.

yeah i guess i was speaking a little out of my *** without full thought. :ughdance: lol

It happens. ;)

Any chance they didn't seat the springs back on the perch correctly? if the rubber mount isn't flush it could force it up a bit. I'm assuming to install the subframe they need to remove the perch mounts.

i think this might be your answer.

This happened to me. Do what Neo said and you will be good to go.

ok thanks for all the input... I will be back at the dealership on friday and hope to sort it all out. I will let you all know how it turns out

I didn't even see Neos input. That's very possible. It could also be the springs not seated properly, as MattP pointed out.

Let us know how the trip to the dealer goes!

Same thing happened to me with my 350z. I was lowered on coilovers, replaced the subframe and the rear sat so much lower than before. I didn't touch the coilovers what so ever. Could never figure it out. Ended up having to do some height adjustment to the spring perch.

Didn't even think of it but if what I said is correct and they do what I mentioned than afterwards your car will sit too low like this member's did.

Since you installed the coilovers with the bushings all set at normal ride height so they were a bit bound up already.

I'll bet like it was said before the rear suspension was tightened when it was unloaded.

Any update on this Josh?

Not yet... Took the car back to Nissan and they claim it's not their issue anymore because of the coilovers so I've decided to drive it around for a few weeks to let things settle a bit before taking it in to the tuning shop who does my alignment. Once I bring it in I'm hoping we can loosen the bushings while the car is sitting on the alignment rack and it'll return to its previous ride height. If not I guess well have to do some adjusting to the coilovers. Interesting though that since I got the car back at the raised rear ride height the rear suspension is almost silent where I previously had some knocking before especially at low speeds.

Did they give you a hard time about replacing your subframe? I'm lowered on just h&r springs and they won't replace my subframe