Albatross

iTrader: (1)

I know man, i've had modified cars since I was a teenager and I'm in my 30's now. The only thing that makes sense is the rear subframe shifting.

the sway bar shouldn't be an issue and here's why. a sway bar basically just tries to keep your tires level. The sway bar bushings only attach it to the car so if they were the issue the car would roll more as opposed to cornering flat.

When the car does what it does its perfectly flat, its just like the rear wheels are steering.

here's my current theory:

1. all control arms are attached to the subframe
2. all control arms are now now soaking up hardly any energy since they went from old rubber bushings to new poly bushings
3. now all of the energy that would've been absorbed by my 12 sloppy control arm bushings is transferred directly to the 4 old rubber subframe bushings.
4. since this happens the subframe acts more like a live axle with crappy mounts than a proper IRS

Imagine in your head the entire rear suspension assembly turning like a tank turret. IF I enter a corner at speed the rear will "settle" but then its predictable as all get out. Its the straights that are scary, ironically enough, which further supports my theory. Without load being put on the rear suspension and with the proper alignment the rear is now neutral so each bump it finds shifts each side equally which means the rear subframe just kind of does whatever it wants uneven roads.

higher the speed the less controllable it is.

when my spacers get here my theory will be validated or i'll just die. I'll just die.

AnonymousG

iTrader: (2)

I wouldn't window weld or use bushing spacers. Just seems like a cheap fix, might as well fix it right and not worry about it anymore. Bushing spacers only last for so long.

Solid subframe bushings are totally dd friendly, think of it this way, lots of cars have the subframe directly bolted on the car.

I daily my car and I have all the mods in my signature. Truthfully, it's a great mod if you you drive your car spirited.

I would suggest getting the battler version rear subframe bushings. That's what I run.

irondonkey

i've used window weld on my motor mounts before.

warning, it's a mess to use. Lol

canman44

Albatross, any updates on this? I think I may have the same thing going on with my car as well. Were you getting any vibration do to this or were you just getting some "wandering" or "self-steering" in the rear? I'm getting that "wandering", especially when changing lanes and you hit that seam in the road between lanes. I feel a pretty good push/pull feeling from it. I'm also getting the "wandering" when just driving on straight and level road too. The faster I go the more intense the self steering is.

I just got done replacing my rear struts last night due to some serious vibration I've been feeling when I hit about 65. I thought my tires were bouncing and thought most of the vibration was stemming from this. Struts did NOT fix the vibration issue although they seemed to help slightly with the wandering. I definitely know what you are talking about when you say "load" the suspension. That seems to help mine sometimes too. I am replacing the front struts this weekend and will see how that does.

Albatross

iTrader: (1)

It was a rear toe link ball joint that apparently completely let loose during reinstallation or the first alignment. I'ce since replaced both sides with some figs toe links and the car is a total beast now in the corners.

I think I'll upgrade to billsteins and better swaybars to cut down on some of the body roll (eventually) but man this sucker sticks in corners like nobody bizniz.

A vibration would indicate something in the drivetrain out of balance, the tires would be the first thing to suspect. heck all of your ball joints under the car. to do this use a pry bar and try to wiggle them. they shouldn't move at all.

canman44

I'll probably be buying new tires for the rear this weekend and getting an alignment done as well, so at least after that I'll be able to rule those sources out. My likeliest suspects are bushing on ball joints. Which ones though? I guess I'll find out. Are poly bushings recommended for ball joints? I see a lot of people suggesting poly for other joints, but Idk if there would be a preference for ball joints.

Did i read in one of your earlier posts that you were even suspecting it could be a diff issue? I'm also thinking that could be a source of my issues too, particularly the wandering, but I honestly don't know enough about the drivetrain to say if that is even a possibility. What was your theory there?

Albatross

iTrader: (1)

a vibration issue could in theory be a diff issue but my issue was different. It felt like something was loose in the back.

If I were you I'd jack up each corner of the car and make sure each wheel spins freely and does not wiggle in any way shape form or fashion. if it does you've found A problem area. then check each thing individually. if the wheel is having trouble spining freely it might be a bearing issue.

canman44

Sorry, meant to reference the diff in regards to the loose steering/wandering issue. I'm also feeling that in the back end. Separate issue from the vibration I think. This is what I was thinking could be the diff. So I recently had the whole back end lifted off the ground and spun one of the wheels and it did not feel entirely smooth. It was also intermittently spin the other wheel the opposite direction. Then I turned the car on so the wheels could spin freely and only one wheel would spin. One of the wheels would get going pretty fast (idling speed) and the other was completely still. If I then stopped both of the wheels and then held the wheel the had been spinning previously then the other wheel (the one that was NOT spinning before) would spin. BUT if I let go of the one I was holding still the other would slow down and the one I had just been holding would start to slowly build up speed until it was spinning again and the other one would slow down until it was completely still again. Not sure if this indicates anything regarding diff functionality.

Albatross

iTrader: (1)

diff wont' cause the wandering i was experiencing. check your ball joints.

bigwhite

I know the feeling of having an issue thats hard to resolve. Hopefully you have another car to drive. My prob. is a wiring issue. I had a low mile 95 sc400 that was driven by a little old lady, that had some wander issues. Like I said before, tires made a big difference. I do not recommend directional. My current 93 sc400 is higher miles, older and runs better with no wander what so ever. It was short term teenager driven, till daddy took the keys away , and sold it to me. Sometimes you just have to walk away for a few days, and go back with renewed strength.

gtsfire

iTrader: (4)

Absolutely this. I've been hating my SC400 for the past few months. Trying to find and eliminate an irritating vibration. I've spent thousands replacing things. It's still there on top of the fact my less than a year old rack is going bad... Have seriously considered buying a MB W215 CL500 or CL55 to replace the SC. Beautiful car and definitely an upgrade in style, but a major downgrade in reliability. It's an itch I'm going to have to scratch no doubt but I can't depend on it as a DD so tomorrow I'll approach the SC with that "renewed strength"... yet again.

adc27

That would be an open differential for ya.

t2d2

iTrader: (8)

I've been searching for this thread for the past couple weeks, trying to remember the appropriate keywords. I think my car may be behaving similarly to what Albatross was wrestling with.

When either rear wheel hits a bump, but especially the right rear, I can feel the tail shift to that side. It's annoying but not super concerning (assuming it doesn't get worse), although I did get a mild scare one day on the highway when the right side of my lane had a stretch of consistent undulations. The tail started wobbling back and forth, building up momentum like Galloping Girtie. The car is super stable at any speed, as long as the rear wheels don't hit bumps.

I've got new factory replacement shocks and Supra rear sway bar, good tires, and fresh alignment. The sway bar end links could use replacing but aren't terrible. I think the problem existed before installing the Supra sway bar, but I can't swear to that. I was thinking lower control arm ball joints are the most likely culprit, but...

Are these the ones you got?

http://shopfigs.com/v1/index.php?rou...product_id=208

Did you go with light, daily, or track duty? How did you determine it was the toe links? Was it obvious visually or did you have to disassemble stuff to spot it? I'll probably bring it by the mechanic with a list of the most likely stuff to look for.

Albatross

iTrader: (1)

yes, those are the ones i got but i had to trim about a quarter inch off the length for my rid height (im not slammed or stock [eibach supra springs]). i informed them of the issue and they said they'd correct it (so give them the heads up when you order).

anyhow, to diagnost get a bar of some sort, jack the car up, and wedge the bar in between each suspension arm and try to wiggle it. if you can wiggle it freely there is your problem. when i found it everything just made perfect sense.

t2d2

iTrader: (8)

^ Awesome, thanks. I'll check for that along with wheel bearings. When you say "wedge the bar," were you using a prybar or something to leverage it, or just grabbing it by hand and feeling for play? Looking at a photo, I guess that's it sort of below, in front of, and parallel to the LCA? Should be pretty easy to get to and determine if it's still intact.

I'm at stock height, so trimming likely wouldn't be required in my case, anyway. Did you by any chance compare the Figs arms to the pretty similar looking Megan Racing ones?

Edit: Here is Figs' personal comparison. Also, it sounds like Megan Racing might be the same as Godspeed, neither of which are well reviewed from what I'm finding. Battle Version is probably a better comparison to Figs.