This past weekend I installed BMR lowering springs, Founders relocation brackets, and UMI LCAs, upper panhard and lower adjustable panhard bar. I initially installed everything per the instructions and with the jackstands under the frame. Once installed I lowered the axle on jackstands and then tightened everything down under load to the specs in the instructions, which I think were 70-80 ft lbs. I made sure the spring isolators were seeded and I adjusted the panhard to center everything. I took it for a test drive and it rides horribly rough and on every bump it sounds like I am hitting the bump stops. It feels like I have zero suspension in the rear. My car was supposed to be 1.25" lower and it is 1/2" lower after the install. I am out of ideas, so any advice or comments would be greatly helpful. Thanks!!

 

How are the shock absorbers.

 

They are KYB Excel-G and they have have about 500 miles on them.

 

OK is there any way that you might have the wrong springs.

 

I was reading in the suspension forum lowering 101. Sounds like you installed correctly

 

What end types did you go with on the LCA's and panhard rod? That will drastically change the way the suspension behaves.

 

Odds are you're somehow out of suspension travel. Put the rear of the car on jack stands and remove the rear springs. Using a floor jack, run the axle up and down in range of normal motion and watch the travel, look for binding, contact to other objects, and when bump stops hit. Also check that the springs don't get into coil bind and shocks don't bottom.

Follow your eyes and nose from there.

 

The LCAs and Panhard are UMI with poly ends.

 

I've installed many different suspension set ups in several thirdgens, and I feel like they never go in the first time perfectly. Always have to loosen and retighten SOMETHING. At least that's how it feels to me! Assume you still have all the old parts, right? I know it's a pain, but a few hours after work or on a saturday should give you enough time to trouble shoot. Springs can be swapped without disconnecting anything, just gotta drop the rear down. LCAs bolt and unbolt quickly. I bet you can find your problem.

....the one thing I don't know about, and I know fitment can be tight, but......double check that UPPER to LOWER panhard clearance. The factory upper is curved to fit the lower upon compression. Depending on what kit you got, maybe something isn't fitting quite right? I might be overthinking as I've never gone aftermarket on the upper.

You were posting as I was posting...
There's certainly a discussion about binding and whether or not poly is ideal, however......even if they're binding a little, it shouldn't cause what you're describing.

 

That is a brilliant idea, but unfortunately my factory LCAs and springs went out in the trash yesterday because I put them in the vicinity of our trash can and my wife assumed they were supposed to go out. I do have my upper and lower panhard (because weren't by the trash can!), although I don't think the lower will work because of the lowering springs, right?
It has been suggested to loosen the bolts to the LCAs and panhard and bounce on the car to see if that will align the suspension. There is no way I can loosen the front bolts of the control arm while it is on the ground. Not enough clearance to get any leverage on a wrench or ratchet. Is there a difference of the car sitting on its tires versus sitting on jackstands? The suspension is loaded either way right?
I just got off the phone with BMR and they are wanting to me to check to see if the shocks are working and not binding and also check the torque arm tunnel to see if it is hitting anywhere in there. Have you heard of this happening when lowering your cars?

 

You could always put the stock panhard rod back on. Your rear end will shift to one side slightly but you can eliminate that as a variable.

 

I wouldn't worry about it for trouble shooting, but technically you are correct. Plenty of people do it day in and day out, and while I don't suggest it, for a grocery getter it's probably fine.

Are you running a factory torque arm? If so, I can't see how it'd be anywhere near touching anything, BUT, never hurts to check. Aftermarket TA's will often have a second set of holes for fitment to various aftermarket rear ends. If you went aftermarket, make sure the arm is installed on set of holes that keeps it as close to the car's centerline as possible. On my 8.8 rear I actually had to cut off the outter holes on my UMI torque arm so it wouldn't hit the trans tunnel, BUT, would fit on the rear. Doesn't sound like that's your issue though.

The suspension needs to be sitting as the car would sit in your driveway when you tighten. I put the rear on jackstands to simulate.

As for the shocks and springs. You should definitely be able to bounce up and down on the rear of the car and simulate compression. Maybe not all the way, but definitely a few inches of travel. You could always unbolt the shocks from the rear and see if that help. (I wouldn't DRIVE it like that). -but you could use body weight and bounce. You should be able to "bounce" the rear of the car easier than the front. I know, not an exact science, but should be more than enough to see if the shocks and springs are working.

Like I said earlier though....go through every bolt. Loosen 'em up and try your "bounce" test again. Make sure to re tighten.

 

I guess doing things the easy way just isn't in the plan.

 

Did you trim your bump stop after lowering it?

usually cut mine in half so there is some suspension travel

 

I haven't trimmed the bump stop, but that was suggested by someone else as well. They said to take off about an inch. Is that what you have done? I need to see if anything else will hit it goes an inch or so higher than the existing stop location.

 

I've never trimmed my bumpstops, and I've had my cars fairly low. I won't say that I NEVER bottomed out, but certainly not often enough to warrant cutting the bumpstops. ...and I'm not suggesting anyone is right or wrong for doing so, but simply giving some context. If the suspension was super floaty, then I get it. You said it rides really rough, which suggests it's not traveling like it should.

I love having these conversations, and am all about helping, but at this point I think you really need to just get back up under there and poke around. There's only SO many parts under there, and nothing is overly complex. To fine tune a suspension is another issue entirely, but simply not moving/articulating properly....I mean there's only so many parts.

 

My guess the panhard bars are making contact do to lowering the car. And your new shocks will be trash cause they are not setup to work at the lowered ride height so ride quality and handling will probably be worse then factoy. Koni yellows are a must have.

 

Here are pics of the springs sitting on the tires. Do these look like they should? I don't know what a binding spring looks like. Do they need to sitting in a certain spot on the lower or upper seats, i.e. I need to rotate them?
Bumpstop distance while on the tires was 7/8" on the passenger and 1 1/2" on the drivers.
Also are pics in each direction of the upper support and lower panhard. No visual marks on the bars, so I don't think they are not hitting. The panhard is angled up towards the drivers side (Driver is 11" off ground and Passenger is 7 1/2"). One thing I did notice is the sway bar seems high compared to what it was before. I swear the bar was right below differential and now it is even with the bolts. I changed out the swaybar endlinks and tightened them underload. Do I need to tighten them more to bring the bar down?
LCAs are in the higher holes on the relocation brackets (Founders has two hole options) and are parallel to the ground while sitting on the tires.

 

The sway bar will move "up" a little, relative to the rear diff cover when you lower. ....Kinda hard to see in the pictures, but things "appear" ok after a quick glance. That panhard is way out of level though. I understand you're saying it's NOT hitting, but in my mind, it sure seems like it's a very real possibility. 3.5" is a LOT, and even if it's NOT hitting.....it's certainly not ideal.

 

Even if you can't SEE a problem, I'd still do what qwiktrip said. Pull the springs and use a jack to simulate range of motion.

 

First off, thanks again to everyone for all the suggestion and help. I reinstalled everything again this past weekend. I regreased all the areas of the attachment points of the suspension and checked to make sure the shocks were going up and down without issue. The only thing I did different on this install was loaded the suspension by sitting the car down on cribs versus jackstands under the axles. After driving it for amount 50 miles today on some pretty crappy Missouri roads, I found it is still harsh and I hear clunking over the bigger bumps in the road. Every bump feels like I am going to jar off body and interior panels. I did recenter the axle. No issues with clearance on the torque arm. I did apply some grease to see if the bumpstops are hitting and it also looked like at some point the over the axle portion of my exhaust might be hitting the top of the axle, so I put some grease there to (I am running the 3" Hooker cat back).. It sounds metal to metal when I hit, so that might be it. I will know more tomorrow after logging some miles on it again.
I still cant figure out why it rides so harsh other than maybe the KYB Excel Gs aren't providing any dampening because of the lowering spring height. I just assumed a 1/2" of drop wouldn't have an effect on the shocks. I did measure and they appear to have 3"-4" of travel. I am not sure if that is acceptable or in their normal operating range since I didn't measure it before. Anybody running Excel G's with lowering springs? Maybe it is time for Koni Yellows.
The other thing is the height. The car is still only down 1/2". Any other suggestions other than ditching the isolators for 3/4" rubber hose? Thanks!

 

If the exhaust is touching anything, that can DEFINITELY make a racket!!!! The KYB's help to control the bounce, but the springs are what really determine your ride until you're fine tuning. ....another thing since you mentioned "crappy roads"... They'll really show you the difference between stock and modified suspension. Here in NC, our roads are pretty good, and most of the time during casual driving, I can't feel a difference from stock. Find a rough patch though and it can shake your fillings out! I DD an e46 BMW and it's lowered too, and it the same. Good roads you wouldn't know it's not stock, bad roads are ROUGH, pun intended! The price we pay I suppose.

 

Your comparing old worn out sprngs to your new ones this is why your only seeing what seems like a small drop cauaes the stockers are shot and lazy. The kyb's just cant control the ride quality sorry.