Hello,

It's a '94 LS400 Special Edition, 186K miles. I've had it for almost a year as a backup car, it's nice.

The rear end sags when I put in a full tank of gas. The rear wheels pretty much tuck into the fenders, I can feel a difference in handling and ride quality. Do the original springs loose their tension over time, is this a common problem? I'm sure the shocks are original and could stand to be replaced, but that shouldn't affect ride height.

Thank you much,

Stan

 

Found this thread: https://www.clublexus.com/forums/ls4...on-advice.html

Guy's car looked like mine does with a full tank of gas. He replaced the shocks with GR2s and installed new OEM springs, gained about an 1" of ride height in the back. Kind of sounds like the springs loosing tension over time is possible, anyone has comments?

Also, what'd be the best place to get OEM springs from?

Thank you much,

Stan

 

Yes it does effect the ride height, a little. The shocks and springs work together for ride and height. This has been talked about alot. If you search you will get alot of helpful info on what springs and shocks are best and peoples results from thier repairs.

Ya posted that when I was typing. That's one thread I was just looking at. Good searching.

 

Yes, I've seen the idea of worn shocks affecting ride height being discussed, but I don't agree with it (at least, not yet). I'm pretty sure the damper is only responsible for controlling the spring and it's internal pressure isn't capable of holding up the weight of the car. Unless the spring perch would bend, I don't see how the ride height can be affected. The car sits on a spring.

I suppose I could test this by drilling a hole in my old shock while it's still on the car and seeing if the car lowers any, but it will be extremely messy.

In any case, it sounds like a set of new rear springs along with some GR2s would be a good idea. I'd go for the Blistein HDs (I like the adjustable perches and damping should still be reasonable for stock springs, though alot higher) but the rears aren't available for the 1st gen.

Thank you much,

Stan

 

Coil springs typically don't exhibit sag like old leaf springs did. Compression of the top hat insulators can contribute some if flattened out/crushed. The struts and shocks themselves do contain enough pressure to contribute to the ride height. Compress a new one when it is fully extended and see how much effort it takes.

YMMV, I've liked the Tokico Blue HD's. A tad stiffer than the stock replacement GR2's. If the car is sitting pretty low, these like any other strut will be prone to being blown out.

 

Ive replace muine with KYB GR series... and it does raised the height... but you have to do alignment and chamber after you run say 100-500 miles because everything should settled by then.

 

I've compressed dampers -- you really think there is enough pressure to hold a corner of a car? We are talking almost 1,000lbs, you can compress a damper all the way down by hand. Usually, a new set of dampers will have the shaft held down by a plastic string. But, I suppose I could test this by just replacing the rear shocks.

Stan

 

Try to put 30 or 40 pounds up or down with your hand and notice how much the car moves. I bet the springs are getting worn too. I guess it could be a bushing or something helping with the sag.

 

Oh, I know the shocks are worn -- I'm surprised they are still working at all with this many miles on them. But, they do something.. at least some compression left, though rebound is most likely all gone.

I know Toyota had a problem with early 4Runners and saggy rear springs. Not sure if the steel can fatigue like that, loosing it's tensile strength.. I'm not great at classroom physics and engineering, most of my knowledge about these things is from first-hand experience working on cars.

Are the rear shocks a huge pain to replace? I'm assuming the rear seat has to come out. I've done a good few dozen suspension swaps (probably at least 50 lol), but most of them have been on wagons or cars where shock or strut mounts could be accessed from the trunk. I've done a '97 Passat and that was a bit of a pain.

I'll price out a pair of rear springs from the dealership. I'd rather not do it twice, my back and joints aren't as strong as they used to be and while working on the car can be fun, I have better things to do with my time nowadays.

Stan

 

Another wear factor is the control arm bushings. These would also show symptoms of uneven tire wear.

Unless the car has been used for towing and or had a heavy trailer supported, I doubt the springs are sagging and in need of replacement. If so, your local wrecking yard would probably have a full set for ~$100 or much less.

Perhaps someone here has their stock OEM 1-LS springs sitting to get a uncompressed measurement from. That way when you remove you can roughly see if there is a spring height issue.

 

dead shocks=lowered height.

swap shocks, keep old springs, will ride fine.

 

Yeah, that's what I'll probably end up doing, starting with the back. Front should be easier. Looking at pictures from the thread I mentioned above, the new and old springs looked to be about the same height. I think GR2s should be fine.

Stan

 

Yup - give it a try. I hope it works for you. Please take measurements and let us know your results 'cuz I'm the one that replaced with OEM springs - maybe we can save someone else from buying new springs if not necessary

 

Update.

I got some KYB shocks and a set of used Eibach springs (ProKit?). I was able to find some time to install the fronts and so far so good. Ride is surprisingly nice and height is still livable, though almost too low for driving around here.

Here's what the car looked like with original shocks and springs and a full tank of gas:



OEM front spring in the middle, the Eibach fronts are on the sides:



Old and new shocks and springs:



OEM bumpstops were gone, I used some spares off a Subaru:



This is what it looks like with new fronts and original rears, tank close to empty:



Now just need time to do the rears.

Stan

 

looks good. where'd you find the 1st gen eibach? DonCorleone?